Note: Descriptions are shown in the official language in which they were submitted.
ANTIMICROBIAL GAS RELEASING AGENTS AND
SYSTEMS AND METHODS FOR USING THE SAME
BACKGROUND OF THE INVENTION
Field of the Invention
[0001] This invention relates to systems and methods for reducing and
preventing the growth
of microbes, or for killing microbes, within an interior space of a container
and/or on
product/good that is stored in the package. More particularly, the invention
relates to systems
and methods for reducing and preventing growth of microbes, or for killing
microbes, e.g.,
in food containers, using polymers entrained with antimicrobial releasing
agents.
Description of Related Art
[0002] There are many items that are preferably stored, shipped and/or
utilized in an
environment that must be controlled and/or regulated. For example, in the
moisture control
field, containers and/or packages having the ability to absorb excess moisture
trapped therein
have been recognized as desirable. Likewise, in packaging products that carry
a risk of
contamination, e.g., food, it may be desirable to control the growth and
proliferation of
microbes.
[0003] Food products, particularly sliced or cut fresh foodstuffs such as
meat, poultry, fruit,
and vegetables are typically stored and sold in a supporting container, e.g.,
tray, that is
overwrapped by a transparent plastic film, enabling visual inspection of the
food products.
These food products generally produce an exudate (i.e., juices), which can be
a source for
the growth of microbial agents. In addition, contamination of processing
equipment or other
surfaces with which the food products come into contact may remain with the
food and
proliferate while packaged. Similarly, food products may be contaminated even
before the
packaging process. For example, a tomato may have an opening in its skin
through which
unwanted microorganisms enter and replicate. Breakdown in the food handling
process
and/or cold chain management (e.g., refrigeration during food transport breaks
for several
hours) can allow microbial growth of contaminated food, potentially leading to
outbreaks of
food borne illness. Regardless of the source or nature of microbial
contamination in food,
the shelf-life and safety of the contaminated food products is affected by
contamination and
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proliferation of microbes.
100041 One way that the food industry has addressed problems associated with
foodstuffs is
by including food grade preservatives as a component of the food, such as
potassium sorbate,
sodium benzoate and nitrites. However, such preservatives are regarded by some
in the
health field and consumers as being unnatural and presenting health risks.
Moreover, it is
not practical to use such preservatives with non-processed foods, for example
fresh fruits or
vegetables.
[0005] Another way that the food industry has addressed food safety is to
utilize
antimicrobial agents that directly contacts the food as a component in
packaging material.
However, such direct contact may be undesirable in some applications.
[0006] For certain applications, it is desirable to provide antimicrobial
agents to release
antimicrobial gas into a headspace of the food product package or container to
control the
growth of microbes, as compared to a solid or liquid component that requires
direct contact
with the stored food in order to be effective. However, there are challenges
with providing
the antimicrobial gas in the headspacc. One such challenge is attaining a
desired release
profile of antimicrobial gas within the headspace during a designated time
period. Failure to
attain the appropriate release profile for a given product may result in a
failure to achieve the
desired shelf life for that product. Thus, there exists a need for improved
delivery of
antimicrobial agents to control, reduce and substantially destroy microbial
contamination in
food packaging as well as other applications, such as but not limited to,
packaging of
sterilized disposable medical devices. A challenge in meeting this need is
maintaining a
balance between providing sufficient antimicrobial gas in the package
headspace to
effectively control and/or kill pathogens while not "overdosing" the package
headspace,
which could adversely affect the quality of the product, e.g., by organoleptic
degradation.
SUMMARY OF THE INVENTION
[0007] Accordingly, in one aspect, the invention provides an entrained polymer
comprising
a base polymer, a chlorine dioxide gas releasing agent, and a channeling
agent. The chlorine
dioxide gas releasing agent includes an active component, a catalyst, and a
trigger.
Optionally, the entrained polymer on a per gram basis releases the chlorine
dioxide gas in a
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concentration of 3 ppm to 1000 ppm, optionally 10 ppm to 1000 ppm, optionally
30 ppm to
1000 ppm, optionally 60 ppm to 1000 ppm, optionally 100 ppm to 1000 ppm,
optionally 150
ppm to 1000 ppm, optionally 200 ppm to 1000 ppm, optionally 50 ppm to 800 ppm,
optionally 100 ppm to 800 ppm, wherein the concentration is measured using the
entrained
polymer in a quantity of 2 grams placed in a 1 L chamber at 25 C in the
presence of 1 g of
water, wherein the 1 g of water is sequestered to a piece of filter paper
having no direct
contact with the entrained polymer.
[0008] Optionally, under the aforementioned conditions, the entrained polymer
releases the
chlorine dioxide gas in a concentration of at least 3 ppm, optionally at least
10 ppm,
optionally at least 50 ppm, optionally at least 100 ppm, optionally at least
150 ppm, or
optionally at least 300 ppm 1 hour post-initiation.
[0009] Optionally, in any embodiment, the chlorine dioxide gas releasing agent
is provided
in at least one entrained polymer article located within the interior space.
The entrained
polymer article is a monolithic material that includes a base polymer, the
chlorine dioxide
gas releasing agent and a channeling agent. Preferably, such entrained polymer
is provided
as a film having a thickness of from 0.1 mm to 1.0 mm, preferably from 0.2 mm
to 0.6 mm,
optionally about 0.2 or 0.3 mm. Alternatively, such entrained polymer may be
produced in
a hot melt application in which the entrained polymer composition has a melt
flow index in
a range from 200 g/10 min to 5000 g/10 min under the ASTM D1238 / ISO 1133
conditions.
Optionally, such entrained polymer composition has a viscosity in a range from
1,000 cp to
50,000 cp, when viscosity is measured with a rheometer at 190 C after
shearing at 5 Hz for
two minutes. Hot melt dispensing apparatus and methods, which may optionally
be used to
dispense an entrained polymer comprising chlorine dioxide releasing agents,
are described
in PCT/US2018/049578, which is incorporated by reference herein in its
entirety.
100101 Accordingly, in one aspect, the invention provides a system to inhibit
or prevent
growth of microbes and/or to kill microbes in a closed container having a good
that is located
therein. The system optionally includes a container including a bottom
surface, a top
opening, one or more sidewalls extending in a vertical direction from the
bottom surface to
the top opening, an interior space formed by the one or more sidewalls, a
headspace formed
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by the interior space that is not occupied by the good, and a cover to close
and/or seal the
container. The system also includes at least one entrained polymer article
located within the
interior space that includes a monolithic material, which includes a base
polymer, and an
antimicrobial releasing agent configured to release a released antimicrobial
gas. The system
further includes a selected material present in the interior space to activate
the release of the
released antimicrobial gas.
100111 In another aspect, the invention provides a method for inhibiting or
preventing the
growth of microbes and/or for killing microbes in a closed container having a
good located
therein. The method includes forming at least one entrained polymer article,
which includes
obtaining a base polymer, and combining an antimicrobial releasing agent with
the base
polymer to form a monolithic material, wherein the antimicrobial releasing
agent is
configured to release a released antimicrobial material in gas form upon being
activated by
a selected material, e.g., moisture. The method also includes obtaining a
container that
includes a bottom surface, a top opening, one or more sidewalls extending in a
vertical
direction from the bottom surface to the top opening, an interior space formed
by the one or
more sidewalls, a headspace formed by the interior space that is not occupied
by the good,
and a cover to close and/or seal the container. The method further includes
positioning the
at least one entrained polymer article within the interior space of the
container; placing the
good in the container; covering the container; presenting the selected
material in the interior
space of the container; and releasing the released antimicrobial material
within the interior
space in a concentration effective for reducing or preventing the growth of
microbes and/or
for killing microbes present in and/or on the good.
[0012] In another aspect, a package is provided for inhibiting or preventing
growth of
microbes and/or for killing microbes in a closed container having a product
located therein.
The package includes a closed container defining an interior space therein. A
product
(optionally a food product) is provided within the interior space. A headspace
is formed
within a volume of the interior space that is not occupied by the product. An
antimicrobial
releasing agent is disposed within the interior space, the antimicrobial
releasing agent
releasing chlorine dioxide gas into the headspace by reaction of moisture with
the
antimicrobial releasing agent. The antimicrobial releasing agent is provided
in an amount
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that releases the chlorine dioxide gas to provide a headspace concentration of
from 6 parts
per million (PPM) to 35 PPM for a period of 10 hours to 36 hours, optionally
from 15 PPM
to 30 PPM for a period of 16 hours to 36 hours, optionally from 15 PPM to 30
PPM for a
period of about 24 hours.
[0013] Optionally, in any embodiment, when the product is provided within the
interior
space, the product is contaminated by at least one type of pathogen. The
antimicrobial
releasing agent provides a controlled release of chlorine dioxide gas to
effectuate, after a
span of 2 days, optionally 3 days, optionally 4 days, optionally 5 days,
optionally 6 days,
optionally 7 days, optionally 8 days, optionally 9 days, optionally 10 days,
optionally 11
days, optionally 12 days, optionally 13 days from when the product is provided
within the
interior space and under storage conditions of 7 C, at least a 1 log base 10
reduction in
colony forming units per gram (CFU/g), optionally at least a 2 log base 10
reduction in
CFU/g, optionally at least a 3 log base 10 reduction in CFU/g, of the at least
one type of
pathogen, optionally at least a 4 log base 10 reduction in CFU/g, of the at
least one type of
pathogen. Optionally, the at least one pathogen is Salmonella, E. Coli,
Listeria and/or
Geotrichum.
100141 Optionally, if the product is a food product and the amount of
antimicrobial releasing
agent and/or chlorine dioxide gas is present in an amount sufficient to
effectuate the at least
1 log base 10 reduction in CFU/g (or at least 2 log base 10 reduction or at
least 3 log base 10
reduction or at least 4 log base 10 reduction in CFU/g), of the at least one
type of pathogen,
such efficacy does not come at the expense of organoleptic degradation of the
food product.
For example the food product is not bleached or otherwise discolored, as
perceived by an
ordinary consumer without special detection equipment (i.e., no substantial
organoleptic
degradation).
100151 Optionally, in any embodiment, the antimicrobial releasing agent is
provided in at
least one entrained polymer article located within the interior space. The
entrained polymer
article is a monolithic material that includes a base polymer, the
antimicrobial releasing agent
and optionally a channeling agent. Preferably, such entrained polymer is
provided as a film
having a thickness of from 0.1 mm to 1.0 mm, preferably from 0.2 mm to 0.6mm,
optionally
about 0.3 mm. Preferably, such film is provided above the midline (preferably
at least 2/3 or
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3/4) of the container sidewalls, which inventors have found helps to attain a
desired
antimicrobial gas release profile.
[0016] Optionally, in any embodiment, the antimicrobial releasing agent is a
powdered
mixture comprising an alkaline metal chlorite, preferably sodium chlorite. The
powdered
mixture further comprises at least one catalyst, optionally sulfuric acid
clay, and at least one
humidity trigger, optionally calcium chloride.
[0017] Optionally, in any embodiment, a method is provided for inhibiting or
preventing the
growth of microbes and/or for killing microbes in a closed container having a
food product
located therein. The method includes providing a closed container defining an
interior space
therein and a food product within the interior space. A headspace is formed
within a volume
of the interior space that is not occupied by the product. An antimicrobial
releasing agent
(such as that disclosed in this Summary section and elsewhere in this
specification) is
provided in the interior space. The agent releases an antimicrobial gas into
the headspace by
reaction of moisture with the antimicrobial releasing agent. The antimicrobial
releasing agent
is provided in an amount sufficient to release the antimicrobial gas to
provide a desired
headspace concentration of the antimicrobial gas over a predetermined amount
of time.
According to the method, if the product is contaminated by at least one type
of pathogen at
the time the product is provided within the interior space, the antimicrobial
releasing agent
optionally provides a controlled release of antimicrobial gas to effectuate,
after a span of 2
days, optionally 3 days, optionally 4 days, optionally 5 days, optionally 6
days, optionally 7
days, optionally 8 days, optionally 9 days, optionally 10 days, optionally 11
days, optionally
12 days, optionally 13 days from when the product is provided within the
interior space and
under storage conditions of 7 C, at least a 1 log base 10 reduction in colony
forming units
per gram (CFU/g), optionally at least a 2 log base 10 reduction in CFU/g,
optionally at least
a 3 log base 10 reduction in CFU/g, of the at least one type of pathogen,
optionally at least a
4 log base 10 reduction in CFU/g, of the at least one type of pathogen.
Preferably, this method
effectuates the reduction without causing substantial or reasonably
perceptible (to the
consumer) organoleptic degradation of the food product, for example without
bleaching or
otherwise causing noticeable discoloration of the food product. Preferably,
the antimicrobial
releasing agent is provided in an entrained polymer more preferably in an
entrained polymer
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film, for example as described herein.
[0018] Optionally, in any embodiment of a package described herein, an aspect
of the
invention may include use of the package for storing a food product, wherein
the food
product exudes moisture that activates the antimicrobial releasing agent to
release chlorine
dioxide gas in the headspace. This use may attain desired headspace
antimicrobial vas
concentrations as described herein. This use may effectuate, after a span of 2
days, optionally
3 days, optionally 4 days, optionally 5 days, optionally 6 days, optionally 7
days, optionally
8 days, optionally 9 days, optionally 10 days, optionally 11 days, optionally
12 days,
optionally 13 days from when the product is provided within the interior space
and under
storage conditions of 7 C, at least a 1 log base 10 reduction in colony
forming units per
gram (CFU/g), optionally at least a 2 log base 10 reduction in CFU/g,
optionally at least a 3
log base 10 reduction in CFU/g, of the at least one type of pathogen,
optionally at least a 4
log base 10 reduction in CFU/g, of the at least one type of pathogen. This is
preferably done
without causing substantial organoleptic degradation of the food product, for
example
without noticeably bleaching or otherwise discoloring the food product.
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BRIEF DESCRIPTION OF THE DRAWINGS
[0019] The invention will be described in conjunction with the following
drawings in which
like reference numerals designate like elements and wherein:
100201 FIG. 1 is a perspective view of a plug formed of an entrained polymer
according to
an optional embodiment of the present invention.
[0021] FIG. 2 is a cross section taken along line 2-2 of FIG. 1;
[0022] FIG. 3 is a cross section similar to that of FIG. 2, showing a plug
formed of another
embodiment of an entrained polymer according to an optional embodiment of the
present
invention;
[0023] FIG. 4 is a schematic illustration of an entrained polymer according to
an optional
embodiment of the present invention, in which the active agent is an
antimicrobial gas
releasing material that is activated by contact with a selected material
(e.g., moisture).
[0024] FIG. 5 is a cross sectional view of a sheet or film formed of an
entrained polymer
according to an optional embodiment of the present invention, adhered to a
barrier sheet
substrate.
[0025] FIG. 6 is a cross section of a package that may be formed using an
entrained polymer
according to an optional embodiment of the present invention.
[0026] FIG. 7 is a perspective view of an exemplary package incorporating
entrained
polymer films according to an optional aspect of the present invention.
[0027] FIGS. 8A and 8B are plots comparing Geotrichum Growth on contaminated
tomatoes
stored in packages respectively with and without use of antimicrobial
entrained polymer
film.
[0028] FIG. 9 is a plot showing the measured amount of C102 (chlorine dioxide)
provided
within a headspace of a container including entrained polymer film, in
accordance with
certain embodiments of the invention.
[0029] FIG. 10 is a plot showing the measured amount of C102 provided within a
headspace
of a container including an entrained polymer film positioned at varying
heights on the
sidcwall, in accordance with certain embodiments of the invention.
100301 FIG. 11 is a plot showing the log CFU/gram reduction in Salmonella for
foodstuff
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2
stored in containers with an entrained polymer film being positioned therein,
in accordance
with certain embodiments, as compared to containers absent of the entrained
polymer film.
[0031] FIG. 12 is a plot showing the log CFU/gram reduction in E. Colt for
foodstuff stored
in containers with an entrained polymer film being positioned therein, in
accordance with
certain embodiments, as compared to containers without the entrained polymer
film.
[0032] FIG. 13 is a plot showing the log CFU/gram reduction in Listeria for
foodstuff stored
in containers with an entrained polymer film being positioned therein, in
accordance with
certain embodiments, as compared to containers without the entrained polymer
film.
100331 FIG. 14 is a plot showing the measured amounts of C102 provided within
a headspace
of a container depending on the amount of entrained antimicrobial polymer film
provided in
the container.
[0034] FIG. 15 is a first plot showing the measured amounts of C102 provided
within a
headspace under Method Two conditions described in the Detailed Description.
100351 FIG. 16 is a second plot showing the measured amounts of C102 provided
within a
headspace under Method Two conditions described in the Detailed Description.
[0036] FIG. 17 is a third plot showing the measured amounts of C102 provided
within a
headspace under Method Two conditions described in the Detailed Description.
[0037] FIG. 18 is a fourth plot showing the measured amounts of C102 provided
within a
headspace under Method Two conditions described in the Detailed Description.
[00381 FIG. 19 is a fifth plot showing the measured amounts of C102 provided
within a
headspace under Method Two conditions described in the Detailed Description.
[0039] FIG. 20 is a first plot showing the measured amounts of C102 provided
within a
headspace under Method One conditions described in the Detailed Description.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
Definitions
[0040] As used herein, the term "active" is defined as capable of acting on,
interacting with
or reacting with a selected material (e.g., moisture or oxygen) according to
the invention.
Examples of such actions or interactions may include absorption, adsorption or
release (for
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CA 3043566 2019-06-07
example, as a result of a chemical reaction) of the selected material. Another
example of
"active", which is pertinent to a primary focus of the present invention is an
agent capable
of acting on, interacting with or reacting with a selected material in order
to cause release of
a released material.
100411 As used herein, the term "active agent" is defined as a material that
(1) is preferably
immiscible with the base polymer and when mixed and heated with the base
polymer and
the channeling agent, will not melt, i.e., has a melting point that is higher
than the melting
point for either the base polymer or the channeling agent, and (2) acts on,
interacts or reacts
with a selected material. The term "active agent" may include but is not
limited to materials
that absorb, adsorb or release (for example, as a result of a chemical
reaction) of the selected
material(s). The active agents of primary focus in this specification are
those that release
antimicrobial gas(es), preferably chlorine dioxide gas, upon contact with the
selected
material(s).
[0042] The term "antimicrobial releasing agent" refers to an active agent that
is capable of
releasing a released antimicrobial material, e.g. in gas form. This active
agent includes an
active component and other components (such as a catalyst and trigger) in a
formulation
(e.g., powdered mixture) configured to release the antimicrobial material,
e.g. antimicrobial
gas. A "released antimicrobial material" is a compound that inhibits or
prevents the growth
and proliferation of microbes and/or kills microbes, e.g., chlorine dioxide
gas. The released
antimicrobial material is released by the antimicrobial releasing agent. By
way of example
only, an antimicrobial releasing agent may be activated (e.g., by chemical
reaction or
physical change) by contact with a selected material (such as moisture). For
example,
moisture may react with an antimicrobial releasing agent to cause the agent to
release a
released antimicrobial material.
[0043] As used herein, the term "base polymer" is defined as a polymer
optionally having a
gas transmission rate of a selected material that is substantially lower than,
lower than or
substantially equivalent to, that of the channeling agent. By way of example,
such a
transmission rate is a water vapor transmission rate in embodiments where the
selected
material is moisture and the active agent is an antimicrobial gas releasing
agent that is
activated by moisture. This active agent includes an active component and
other components
CA 3043566 2019-06-07
in a formulation configured to release the antimicrobial gas. The primary
function of the base
polymer is to provide structure for the entrained polymer. The base polymer
also enables
molding or extruding an article having a monolithic composition.
100441 Suitable base polymers for use in the invention include thermoplastic
polymers, e.g.,
polyolefins such as polypropylene and polyethylene, polyisoprene,
polybutadiene,
polybutene, polysiloxane, polycarbonates, polyamides, ethylene-vinyl acetate
copolymers,
ethylene-methacrylate copolymer, poly(vinyl chloride), polystyrene,
polyesters,
polyanhydrides, polyacrylonitrile, polysulfones, polyacrylic ester, acrylic,
polyurethane and
polyacetal, or copolymers or mixtures thereof.
100451 In certain embodiments, the channeling agent has a water vapor
transmission rate of
at least two times that of the base polymer. In other embodiments, the
channeling agent has
a water vapor transmission rate of at least five times that of the base
polymer. In other
embodiments, the channeling agent has a water vapor transmission rate of at
least ten times
that of the base polymer. In still other embodiments, the channeling agent has
a water vapor
transmission rate of at least twenty times that of the base polymer. In still
another
embodiment, the channeling agent has a water vapor transmission rate of at
least fifty times
that of the base polymer. In still other embodiments, the channeling agent has
a water vapor
transmission rate of at least one hundred times that of the base polymer.
[0046] As used herein, the term "channeling agent" or "channeling agents" is
defined as a
material that is immiscible with the base polymer and has an ability to
transport a gas phase
substance at a faster rate than the base polymer. Optionally, a channeling
agent is capable of
forming channels through the entrained polymer when formed by mixing the
channeling
agent with the base polymer. Optionally, such channels are capable of
transmitting a selected
material through the entrained polymer at a faster rate than in solely the
base polymer.
[0047] As used herein, the term "channels" or "interconnecting channels" is
defined as
passages formed of the channeling agent that penetrate through the base
polymer and may
be interconnected with each other.
[0048] As used herein, the term "entrained polymer" is defined as a monolithic
material
formed of at least a base polymer with an active agent and optionally also a
channeling agent
entrained or distributed throughout. An entrained polymer thus includes two-
phase polymers
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(without a channeling agent) and three-phase polymers (with a channeling
agent).
100491 As used herein, the term "monolithic," "monolithic structure" or
"monolithic
composition" is defined as a composition or material that does not consist of
two or more
discrete macroscopic layers or portions. Accordingly, a "monolithic
composition" does not
include a multi-layer composite (although could be used as a component of such
a
composite).
100501 As used herein, the term "phase" is defined as a portion or component
of a monolithic
structure or composition that is uniformly distributed throughout, to give the
structure or
composition its monolithic characteristics.
100511 As used herein, the term "selected material" is defined as a material
that is acted
upon, by, or interacts or reacts with an active agent and is capable of being
transmitted
through the channels of an entrained polymer. For example, in embodiments in
which a
releasing material is the active agent, the selected material may be moisture
that reacts with
or otherwise causes the active agent to release a releasing material, such as
an antimicrobial
gas.
100521 As used herein, the term "three phase" is defined as a monolithic
composition or
structure comprising three or more phases. An example of a three phase
composition
according to the invention is an entrained polymer formed of a base polymer,
active agent,
and channeling agent. Optionally, a three phase composition or structure may
include an
additional phase, e.g., a colorant, but is nonetheless still considered "three
phase" on account
of the presence of the three primary functional components.
[0053] Furthermore, the terms "package," "packaging" and "container" may be
used
interchangeably herein to indicate an object that holds or contains a good,
e.g., food product
and foodstuffs. Optionally, a package may include a container with a product
stored therein.
Non- limiting examples of a package, packaging and container include a tray,
box, carton,
bottle receptacle, vessel, pouch and flexible bag. A pouch or flexible bag may
be made from,
e.g., polypropylene or polyethylene. The package or container may be closed,
covered and/or
scaled using a variety of mechanisms including a cover, a lid, lidding
sealant, an adhesive
and a heat seal, for example. The package or container is composed or
constructed of various
materials, such as plastic (e.g., polypropylene or polyethylene), paper,
Styrofoam, glass,
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metal and combinations thereof. In one optional embodiment, the package or
container is
composed of a rigid or semi-rigid polymer, optionally polypropylene or
polyethylene, and
preferably has sufficient rigidity to retain its shape under gravity.
Exemplary Entrained Polymers
[0054] Conventionally, desiccants, oxygen absorbers and other active agents,
for example
the antimicrobial releasing agent of the present invention, have been used in
raw form, e.g.,
as loose particulates housed in sachets or canisters within packaging, to
control the internal
environment of the package. For many applications, it is not desired to have
such loosely
stored active substances. Thus, the present application provides active
entrained polymers
comprising active agents, wherein such polymers can be extruded and/or molded
into a
variety of desired forms, e.g., container liners, plugs, film sheets, pellets
and other such
structures. Optionally, such active entrained polymers may include channeling
agents, such
as polyethylene glycol (PEG), and vinylpyrrolidone-vinyl acetate copolymer
(PVPVA),
which form channels between the surface of the entrained polymer and its
interior to transmit
a selected material (e.g., moisture) to the entrained active agent (e.g.,
desiccant to absorb the
moisture). As explained above, entrained polymers may be two phase
formulations (i.e.,
comprising a base polymer and active agent, without a channeling agent) or
three phase
foimulations (i.e., comprising a base polymer, active agent and channeling
agent). Entrained
polymers comprising channeling agents are described, for example, in U.S. Pat.
Nos.
5,911,937, 6,080,350, 6,124,006, 6,130,263, 6,194,079, 6,214,255, 6,486,231,
7,005,459,
and U.S. Pat. Pub. No. 2016/0039955, each of which is incorporated herein by
reference as
if fully set forth.
100551 Figs. 1-6 illustrate exemplary entrained polymers 20 and various
packaging
assemblies formed of entrained polymers according to certain embodiments of
the invention.
The entrained polymers 20 each include a base polymer 25, optionally a
channeling agent
35 and an active agent 30. As shown, the channeling agent 35 forms
interconnecting channels
45 through the entrained polymer 20. At least some of the active agent 30 is
contained within
these channels 45, such that the channels 45 communicate between the active
agent 30 and
the exterior of the entrained polymer 20 via channel openings 48 formed at
outer surfaces of
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the entrained polymer 25. The active agent 30 can be, for example, any one of
a variety of
antimicrobial releasing materials, as described in further detail below. While
a channeling
agent, e.g., 35, is preferred, the invention broadly includes entrained
polymers that optionally
do not include a channeling agent.
100561 Suitable channeling agents include polyglycol such as polyethylene
glycol (PEG),
ethylene-vinyl alcohol (EVOH), polyvinyl alcohol (PVOH), glycerin polyamine,
polyurethane and polycarboxylic acid including polyacrylic acid or
polymethacrylic acid.
Alternatively, the channeling agent 35 can be, for example, a water insoluble
polymer, such
as a propylene oxide polymerisate-monobutyl ether, which is commercially
available under
the trade name Polyglykol B01/240, produced by CLARIANT. In other embodiments,
the
channeling agent could be a propylene oxide polymerisate monobutyl ether,
which is
commercially available under the trade name Polyglykol B01/20, produced by
CLARIANT,
propylene oxide polymerisate, which is commercially available under the trade
name
Polyglykol D01/240, produced by CLARIANT, ethylene vinyl acetate, nylon 6,
nylon 66, or
any combination of the foregoing. Alternatively, the channeling agent 35 can
also be a water
soluble agent, such as vinylpyrrolidone-vinyl acetate copolymer 60/40 (PVPVA
64). Certain
propylene oxide polymerisate-monobutyl ethers are also water soluble.
[0057] Entrained polymers with antimicrobial releasing agents are further
described below.
Antimicrobial Releasing Agents and Optional
Entrained Polymer Formulations Incorporating the Same
[0058] Suitable active agents according to the invention include antimicrobial
releasing
agents. FIG. 4 illustrates an embodiment of an entrained polymer 10 according
to the
invention, in which the active agent 30 is an antimicrobial releasing agent.
The arrows
indicate the path of a selected material, for example moisture or another gas,
from an exterior
of the entrained polymer 10, through the channels 45, to the particles of
active agent 30 (in
this case, an antimicrobial releasing agent). Optionally, the antimicrobial
releasing agent
reacts with or is otherwise triggered or activated by the selected material
(e.g., by moisture)
and in response releases a released antimicrobial material, preferably in gas
form.
[00591 The antimicrobial agents useful herein include volatile antimicrobial
releasing
agents, non-volatile antimicrobial releasing agents and combinations thereof.
14
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100601 The term "volatile antimicrobial releasing agent" includes any compound
that when
it comes into contact with a fluid (e.g., water or the juice from a food
product), produces a
gas and/or gas phase such as vapor of released antimicrobial agent. As will be
discussed in
greater detail below, the volatile antimicrobial releasing agent is generally
used in a closed
system so that the released antimicrobial material (gas and/or vapor) does not
escape.
[00611 The term "non-volatile antimicrobial agent" includes any compound that
when it
comes into contact with a fluid (e.g., water or the juice from a food
product), produces
minimal to no vapor of antimicrobial agent. Examples of non-volatile
antimicrobial agents
include, but are not limited to, ascorbic acid, a sorbate salt, sorbic acid,
citric acid, a citrate
salt, lactic acid, a lactate salt, benzoic acid, a benzoate salt, a
bicarbonate salt, a chelating
compound, an alum salt, nisin, e-polylysine 10%, methyl and/or propyl
parabens, or any
combination of the foregoing compounds. The salts include the sodium,
potassium, calcium,
or magnesium salts of any of the compounds listed above. Specific examples
include calcium
sorbate, calcium ascorbate, potassium bisulfite, potassium metabisulfite,
potassium sorbate,
or sodium sorbate.
[00621 Preferred features of antimicrobial releasing agents used according to
an aspect of
the present invention include any one or more of the following
characteristics: (1) they
volatize at refrigerated temperatures; (2) they are food safe and edible in
finished form; (3)
they may be incorporated safely into an entrained polymer formulation or other
mechanism
for release; (4) they are shelf stable in long term storage conditions; (5)
they release the
released antimicrobial material only once a package in which the agent is
disposed, is sealed
with product disposed in the package; (6) they do not substantially affect a
stored food
product organoleptically when they are formulated and configured to achieve a
desired
release profile within the package; and (7) they are preferably acceptable
under applicable
governmental regulations and/or guidelines pertaining to food packaging and
finished food
labeling.
Chlorine Dioxide Releasing Antimicrobial Releasing Agents
[00631 In one aspect of the invention, preferred antimicrobial releasing
agents are volatile
antimicrobial agents that release chlorine dioxide (C107) in gas form as the
released
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antimicrobial material. For example, the antimicrobial releasing agent may be
a compound
or formulation comprising an alkaline chlorite, such as, e.g. sodium chlorite
or potassium
chlorite, a catalyst and a trigger (e.g., in the form of a powder) which in
combination are
triggered or activated by moisture to cause the agent to release chlorine
dioxide. One
exemplary antimicrobial releasing agent is provided under the brand ASEPTROL
7.05 by
BASF Catalysts LLC. This material and preparation of the same is described in
U.S. Pat.
No. 6,676,850, which is incorporated by reference in its entirety. Example 6
of the
aforementioned patent describes a foimulation that is particularly suitable as
an antimicrobial
releasing agent, according to an optional aspect of the invention.
100641 Optionally, a suitable antimicrobial releasing agent, which is
based on Example
6 of U.S. Pat. No. 6,676,850 and is configured to release chlorine dioxide gas
upon activation
by moisture, may be prepared as follows.
100651 The antimicrobial releasing agent includes a formulation comprising
sodium
chlorite (as the active component), a base catalyst and a trigger. The
catalyst and trigger
preparations are made separately, then combined together and ultimately
combined with the
sodium chlorite.
100661 The base catalyst is optionally made by first preparing a 25-30 wt.
% sodium
silicate solution (Si02:Na20 proportion of 2.0 to 3.3 by weight). That
solution is mixed into
an aqueous slurry of 28-44 wt. % Georgia Kaolin Clay (particle size diameter
of about 80%
less than one micrometer), wherein the sodium silicate solution is 2 wt. % of
the slurry. The
slurry is oven dried at 100' C to generate agglomerates or inicrospheres of
about 701.tm in
size. 300g of these microspheres are impregnated with 280g of 2.16N sulfuric
acid solution.
That mixture is then dried at 100 C. Next, the dried mixture undergoes a
calcine process at
350 C for 3 hours, followed by an additional calcine process at 300 C in a
sealed glass jar
with the seal wrapped with tape. This mixture forms the base catalyst.
100671 Next, 84.6 g of the base catalyst are mixed with 10.1 g of the
trigger, dry calcium
chloride. This base catalyst and trigger mixture is ground with mortar and
pestle at ambient
room temperature. This mixture is dried for 2 hours at 200' C. The base
catalyst and trigger
mixture is then cooled to room temperature in a sealed glass jar with tape
wrapped around
the seal.
16
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[00681 Finally,
the base catalyst and trigger mixture is combined with 5.3g of sodium
chlorite (which is the active component of the active agent). The full mixture
is then ground
with mortar and pestle at ambient room temperature, thus forming an optional
embodiment
of an antimicrobial releasing agent. The antimicrobial releasing agent is then
deposited in a
sealed glass jar with tape wrapped around the seal to preserve it and keep it
essentially free
of moisture, which would prematurely activate it (to release chlorine dioxide
gas).
100691 Optionally, the antimicrobial releasing agent is a component of an
entrained polymer,
preferably a three phase polymer comprising the active agent (e.g., 30%-70% by
weight), a
base polymer and a channeling agent (e.g., 1%-16% by weight). Optionally, such
entrained
polymer is in the form of a film disposed within sealed packaging containing
fresh
foodstuffs, e.g., meat or produce.
[0070] It is generally believed that the higher the antimicrobial releasing
agent concentration
in an entrained polymer mixture, the greater the absorption, adsorption or
releasing capacity
of the final composition. However, too high an active agent concentration may
cause the
entrained polymer to be too brittle. This may also cause the molten mixture of
active agent,
base polymer and (if used) channeling agent to be more difficult to either
thermally form,
extrude or injection mold. Furthermore, excessive loadings of the
antimicrobial releasing
agent may cause discoloration or otherwise undesirable organoleptic changes to
the
foodstuffs stored with and exposed to the released antimicrobial gas
(depending on various
factors).
100711 In any embodiment, the antimicrobial releasing agent loading level or
concentration
can range from 20% to 80%, optionally 30% to 70%, optionally 30% to 60%,
optionally 30%
to 50%, optionally from 35% to 70%, optionally from 35% to 60%, optionally
from 35% to
55%, optionally from 35% to 50%, optionally 40% to 70%, optionally from 40% to
60%,
optionally from 40% to 50%, optionally from 45% to 60%, optionally from 50% to
60% by
weight with respect to the total weight of the entrained polymer.
[00721 In any embodiment, , the channeling agent may be provided in a range of
1% to 16%,
optionally I% to 14%, optionally from 1% to 12%, optionally from 1% to 10%,
optionally
from 1% to 8%, optionally from 1% to 6%, optionally from 1% to 5%, optionally
from 1%
17
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to 4%, optionally from 2% to 16%, optionally from 2% to 14%, optionally from
2% to 12%,
optionally from 2% to 10%, optionally from 2% to 8%, optionally from 2% to 6%,
optionally
from 2% to 5%, optionally from 2% to 4%, optionally from 4% to 12%, optionally
from 4%
to 10%, optionally from 4% to 8%, optionally from 4% to 6%, optionally from 4%
to 5%,
optionally from 6% to 12%, optionally from 6% to 10%, optionally from 6% to
8%,
optionally from 8% to 12%, optionally from 8% to 10% by weight of the
entrained polymer.
[0073] In any embodimentõ the base polymer may range from 10% to 70%,
optionally from
20% to 60%, optionally from 20% to 50%, optionally from 20% to 40%, optionally
from
30% to 70%, optionally from 30% to 60%, from 30% to 50%, optionally from 40%
to 70%,
optionally from 40% to 60%, optionally from 40% to 50% by weight of the total
composition.
[0074] Optionally, a colorant is added, e.g., at about 1% to 2% by weight of
the entrained
polymer.
[0075] The invention provides an entrained polymer according to the
composition described
above to provide a wide range of the desired properties characterizing the
released gas. Such
properties include but are not limited to rapidity of or delayed release, rate
of release,
duration of release, peak concentration, and hold pattern. The desired
properties may be
dictated by the foodstuffs or the product to be protected, in combination with
the ambient
humidity level.
100761 As an example, sliced tomatoes are a high moisture exuding food. The
typical time
between farm processing and retail points is about 36-96 hours. To effectively
protect
against food borne pathogens, an entrained polymer with a quick release, a
high released
chlorine dioxide concentration and a sustained released chlorine dioxide
concentration is
necessary. Yet, for commercial acceptance, the released chlorine dioxide may
not bleach
the sliced tomatoes or otherwise noticeably compromise the appearance of the
sliced
tomatoes. In contrast, cut cantaloupe is a low moisture exuding food. A longer
acting
entrained polymer to give a lower but sustained released chlorine dioxide
concentration may
be appropriate. The desired release profile is also dictated by the nature of
the native or
environmental microbes. The entrained polymer of the current invention
provides a wide
18
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range of release profile and serves a broad range of needs that may be
specific to the products
protected.
[0077] In one embodiment, an entrained polymer may be a three phase
formulation including
50% by weight of ASEPTROL 7.05 antimicrobial releasing agent in the form of
the
powdered mixture, 38% by weight ethyl vinyl acetate (EVA) as a base polymer
and 12% by
weight polyethylene glycol (PEG) as a channeling agent.
[0078] FIG. 1 shows a plug 55 constructed of an entrained polymer 20, in
accordance with
certain embodiments of the invention. The plug 55 may be placed inside of a
container. As
aforementioned, the entrained polymer 20 includes a base polymer 25, a
channeling agent
35 and an active agent 30.
[0079] FIG. 2 shows a cross-sectional view of the plug 55 shown in FIG. 1. In
addition, FIG.
2 shows that the entrained polymer 20 has been solidified such that the
channeling agent 35
forms interconnecting channels 45 to establish passages throughout the
solidified plug 55.
At least some of the active agent 30 is contained within the channels 45, such
that the
channels 45 communicate between the active agent 30 and the exterior of the
entrained
polymer 20 via channel openings 48 formed at outer surfaces of the entrained
polymer 25.
In reality, these channels would be much smaller but are shown here
schematically to assist
in understanding the invention.
[0080] FIG. 3
illustrates an embodiment of a plug 55 having similar construction and
makeup to the plug 55 of FIG. 2, where interconnecting channels 45 are finer
as compared
to those shown in FIG. 2. This can result from the use of a dimer agent (i.e.,
a plasticizer)
together with a channeling agent 35. The dimer agent may enhance the
compatibility
between the base polymer 25 and the channeling agent 35. This enhanced
compatibility is
facilitated by a lower viscosity of the blend, which may promote a more
thorough blending
of the base polymer 25 and channeling agent 35, which under normal conditions
can resist
combination into a uniform solution. Upon solidification of the entrained
polymer 20 having
a ditner agent added thereto, the interconnecting channels 45 which are formed
there through
have a greater dispersion and a smaller porosity, thereby establishing a
greater density of
interconnecting channels throughout the plug 55.
19
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100811 Interconnecting channels 45, such as those disclosed herein,
facilitate
transmission of a desired material, such as moisture, gas or odor, through the
base polymer
25, which generally acts as a barrier to resist permeation of these materials.
For this reason,
the base polymer 25 itself acts as a barrier substance within which an active
agent 30 may
be entrained. The interconnecting channels 45 formed of the channeling agent
35 provide
pathways for the desired material to move through the entrained polymer 10.
Without these
interconnecting channels 45, it is believed that relatively small quantities
of the desired
material would be transmitted through the base polymer 25 to or from the
active agent 30.
Additionally, wherein the desired material is transmitted from the active
agent 30, it may be
released from the active agent 30, because the active agent 30 is an
antimicrobial gas
releasing material in the present invention.
[0082] FIG. 5 illustrates an active sheet or film 75 formed of the
entrained polymer 20
used in combination with a barrier sheet 80 to form a composite, according to
an aspect of
the invention. The characteristics of the active sheet 75 are similar to those
described with
respect to the plug 55 shown in FIGs. 1 and 2. The barrier sheet 80 may be a
substrate such
as foil and/or a polymer (such as a container wall) with low moisture or
oxygen permeability.
The barrier sheet 80 is compatible with the active sheet 75 and thus, is
configured to
thermally bond to the active sheet 75, when the active sheet 75 solidifies
after dispensing.
FIG. 6 illustrates an embodiment in which the two sheets 75, 80 are combined
to form a
packaging wrap having active characteristics at an interior surface formed by
the entrained
polymer 20/active sheet 75, and vapor resistant characteristics at an exterior
surface formed
by the barrier sheet 80.
100831 In one embodiment, the sheets 75, 80 of FIG. 5 are joined together
to form an
active package 85, as shown in FIG. 6. As shown, two laminates or composites
are provided,
each formed of an active sheet 75 joined with a barrier sheet 80. The sheet
laminates are
stacked, with each active sheet 75 facing the other, so as to be disposed on
an interior of the
package, and are joined at a sealing region 90, formed about a perimeter of
the sealed region
of the package interior.
100841 Optionally, in any of the foregoing embodiments, the antimicrobial
entrained
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polymer is in the form of a film that is disposed within a sealed food
package. Optionally,
the film may be adhered, e.g., using an adhesive, to an inner surface of the
package.
Alternatively, the film may be heat staked (without an adhesive) to the inner
surface of the
package. The process of heat staking film onto a substrate is known in the art
and described
in detail in U.S. Pat. No. 8,142,603, which is incorporated by reference
herein in its entirety.
The size and thickness of the film can vary. In certain embodiments, the film
has a thickness
of approximately 0.3 mm. Optionally, the film may range from 0.1 mm to 1.0 mm,
more
preferably from 0.3 mm to 0.6 mm.
100851 FIG. 7 shows a package 100 for storing fresh foodstuffs, e.g., produce
or meat, in
accordance with certain embodiments of the invention. The package 100 is shown
in the
form of a plastic tray 102. Although, other forms and materials are also
contemplated as
being within the scope of the invention. The tray 102 comprises a base 104,
and sidewalls
106 extending vertically from the base 104 leading to a tray opening 108. The
base 104 and
sidewalls 106 together define an interior 110, e.g. for holding and storing
fresh produce. The
package 100 also includes a flexible plastic lidding film 112, which is
disposed over and
seals the opening 108. It is contemplated and understood that a wide variety
of covers or lids
may be used to close and seal the opening 108. Optionally, the cover or lid is
transparent,
such that the interior can be viewed. When a product (e.g., sliced tomatoes)
is stored within
the interior 110, empty space surrounding and above the product is herein
referred to as
"headspace" (not shown).
100861 The package 100 further includes sections of antimicrobial entrained
polymer film
114 disposed on the sidewalls 106. In the embodiment shown, there are four
sections of such
film 114, one section of film 114 per sidewall 106. The film 114 is preferably
disposed at or
near the top of the sidewall 106, proximal to the opening 108. At least a
portion, although
preferably most or all of each of the film sections 114 protrude above the
midline 116 of the
sidewall 106, the midline 116 being centrally located between the base 104 and
the opening
108. It has been found that film placement at or towards the top of the
package 100 has an
effect on efficacy of the film sections 114, as such placement facilitates
desirable distribution
of released antimicrobial material into the headspace of the package 100.
Placing the
entrained polymer at too low of a height above the base 104, or beneath the
food in the
21
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package, has been found not to provide desirable distribution of the released
antimicrobial
material in the headspace. If placement mass transfer of the antimicrobial is
not optimal,
some of the food product/good will not be adequately protected against the
growth of
microbes. Additionally, the food may undesirably react with and/or absorb the
released
antimicrobial material. As explained further below, it has been found that
placing the film
above the midline of the sidewall, preferably at a height of at least 67% or
75% or about 80%
of the sidewall, facilitates achieving a desired antimicrobial gas release
profile and headspace
concentration.
100871 Optionally, the entrained polymer film 114 is heat staked to the
package (e.g., on the
sidewall as described and shown vis-à-vis Fig. 7). Advantageously, heat
staking could allow
the film to permanently adhere to the sidewall without use of an adhesive. An
adhesive may
be problematic in some circumstances because it may release unwanted volatiles
in the food-
containing headspace. Aspects of a heat staking process that may be used in
accordance with
optional embodiments of the invention are disclosed in U.S. Pat. No.
8,142,603, as
referenced above. Heat staking, in this instance, refers to heating a sealing
layer substrate on
the sidewall while exerting sufficient pressure on the film and sealing layer
substrate to
adhere the film to the container wall.
[00881 In certain embodiments, the antimicrobial entrained polymer film 114
may be
connected to the surface of the lidding film 112 (or a lid) that is inside of
the container, in
place of the film sections 114 on the sidewall(s) 106, or in addition thereto.
Alternatively,
the antimicrobial entrained polymer film 114 may be incorporated into the
composition of
the lidding film 112 (or a lid). Optionally, the lidding film itself may
include a lid barrier
layer and an antimicrobial entrained polymer film layer beneath it.
100891 In addition to placement of the film 114, another important factor is
the release profile
of the released antimicrobial material. As aforementioned, to ensure adequate
shelf life,
release of the agent must not all occur immediately; rather, release should be
extended,
sustained and predetermined to attain a desired shelf life.
[00901 In general, the polymer entrained with antimicrobial releasing agent is
self-
activating, meaning that release of the released antimicrobial gas is not
initiated until the
antimicrobial releasing agent is exposed to the selected material, e.g.,
moisture. Typically,
22
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moisture is not present in the interior, e.g., headspace, of the container
prior to a food product
being placed inside of the container. Upon placement, the food product
generates moisture
that interacts with the antimicrobial releasing agent entrained in the
polymer, to generate the
antimicrobial releasing agent in the headspace. In one embodiment, the
container is sealed
in a moisture tight manner to trap moisture within the container generated by
moisture-
exuding comestibles.
[0091] In certain embodiments, a controlled release and/or a desired release
profile can be
achieved by applying a coating to the active agent, e.g., using a spray
coater, wherein the
coating is configured to release the released antimicrobial agent within a
desired time frame.
The antimicrobial releasing agents may have different coatings applied thereon
to achieve
different release effects. For example, if a 14-day shelf life is desired,
based on
predetermined relative humidity of the package, the amount of selected
material (moisture)
present to trigger the antimicrobial releasing agent may be determined. Based
on this
determination, the agent may be coated with extended release coatings of
varying thicknesses
and/or properties to achieve the desired release profile. For example, some
active agent will
be coated such that it will not begin releasing released antimicrobial
material until after one
week, while other active agent will begin release almost immediately. Spray
coating
technology is known in the art. For example, pharmaceutical beads and the like
are spray
coated to control the release rate of active ingredient, e.g., to create
extended or sustained
release drugs. Optionally, such technology may be adapted to apply coatings to
the active
agent to achieve a desired controlled rate of release of antimicrobial gas.
[0092] Alternatively, a controlled release and/or desired release profile may
be achieved by
providing a layer, optionally on both sides of the film, of a material
configured to control
moisture uptake into the entrained polymer (which in turn triggers release of
the released
antimicrobial material). For example, the film may include a polymer liner,
made e.g., from
low density polyethylene (LDPE) disposed on either side or both sides thereof
The thickness
of the film and liner(s) can vary. In certain embodiments, the film is
approximately 0.3 mm
thick and the LDPE liners on either side are each approximately 0.02 mm to
0.04 mm thick.
The LDPE liners may be coextruded with the film or laminated thereon.
23
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[0093] Alternatively, a controlled release and/or desired release profile may
be achieved by
modifying the formulation of the trigger of the antimicrobial releasing agent.
For example,
the trigger, when contacted by moisture, liquefies and then reacts with the
active component
(e.g., sodium chlorite) to cause release of the antimicrobial gas. The trigger
may be
formulated to liquefy upon contact with moisture at different rates. The
faster the trigger
liquefies, the faster the release of antimicrobial gas and vice versa. In this
way, modification
of the trigger is yet another vehicle provide a desired release rate of
antimicrobial gas.
[0094] Any combination of the aforementioned mechanisms may be utilized to
achieve
desired release rates and release profiles of antimicrobial gas within a
container headspace.
Varied Release Rates Depending on Nature of Stored Food Product
[0095] The inventors have discovered that the desired release profile of
chlorine dioxide gas
in a container headspace may vary depending on the nature of the product that
is stored. For
example, the inventors have found that foods having a high water content
appear to require
a high burst of antimicrobial gas followed by a drop in headspace
concentration during the
storage period while foods having a more modest water content appear to
respond well to a
relatively steady headspace concentration over the storage period.
[0096] Non-limiting examples of food products that exude high amounts of
moisture and
that are more appropriately protected by a release profile having a quick
burst of chlorine
dioxide gas followed by a drop include sliced, diced or cut foods selected
from the group
consisting of: tomatoes, washed peppers, washed onions, water melon, honey
dew,
cantaloupe, strawberries, peaches, pineapple, oranges, seafood, meat and
poultry. For such
foods, an amount of the antimicrobial releasing agent is provided that
releases the chlorine
dioxide gas to preferably provide a headspace concentration of from 6 parts
per million
(PPM) to 35 PPM for a period of 10 hours to 36 hours, optionally from 10 PPM
to 35 PPM
for a period of 16 to 36 hours, optionally from 15 PPM to 30 PPM for a period
of 16 hours
to 36 hours, optionally from 15 PPM to 30 PPM for a period of about 24 hours.
Headspace
concentration measurements may be obtained, for example, using a PORTASENS II
gas
detector from Analytical Technology, Inc. for readings taken with chlorine
dioxide sensors
placed within the package. The sensors may be one or more of 00-1004 Chlorine
Dioxide,
24
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0-1/5 PPM (2 PPM Std.), 00-1005 Chlorine Dioxide, 0-5/200 (20 PPM Std.) and 00-
1359
Chlorine Dioxide, 0- 200/1000 PPM (1000 PPM Std.), which are also from
Analytical
Technology, Inc. and are compatible with the PORTASENS II gas detector.
[0097] This type of "quick burst" (e.g., headspace concentration of from 10
parts per million
(PPM) to 35 PPM for a period of 16 hours to 36 hours) appears to be required
so that the
chlorine dioxide gas, which dissolves in water, can stay ahead of the
dissolution curve to
provide sufficient antimicrobial effect during the spike in headspace
concentration, to
improve the shelf life of contaminated food over an approximately two-week
period.
Notwithstanding the characterization of the release as "quick burst," it may
still be
considered controlled release because headspace concentration is still
regulated to fall within
a desired concentration over a given period, even if relatively "quick." The
inventors have
found, for example, that the aforementioned headspace concentrations works
well to
significantly reduce the microbial count of contaminated sliced tomatoes over
about thirteen
days without bleaching the tomatoes. This is borne out by examples provided
below.
[0098] Non-limiting examples of food products that exude moderate or low
amounts of
moisture arc whole or minimally processed produce selected from the group
consisting of:
broccoli, brussel sprouts, cabbage, cucumbers, bananas, herbs, whole peppers,
carrots, root
vegetables and potatoes. For such foods, an amount of antimicrobial releasing
agent releases
the chlorine dioxide gas to preferably provide a headspace concentration of
from 8 PPM to
15 PPM for a period of 13 days. Regardless of whether this exact headspace
concentration
is met, it is preferred that the antimicrobial releasing agents are provided
in entrained
polymer films, as described herein, for such low or moderate moisture exuding
foods.
100991 The aforementioned release profiles and headspace concentration assume
the
presence of moisture exuding food product in the package.
101001 In either case (high moisture exuding or moderate/low moisture exuding
foods),
where the product is contaminated by at least one type of pathogen, the
chlorine dioxide gas
is provided in a headspace concentration over a determined time period to
effectuate, after a
span of 2 days from when the product is provided within the interior space and
under storage
conditions of 7 C, at least a I log base 10 reduction in colony forming units
per gram
CA 3043566 2019-06-07
(CFU/g), optionally at least a 2 log base 10 reduction in CFU/g, optionally at
least a 3 log
base 10 reduction in CFU/g of the at least one type of pathogen, without
substantially causing
organoleptic degradation of the food product. Optionally, after a span of 4
days from when
the product is provided within the interior space and under storage conditions
of 7 C, at
least a 1 log base 10 reduction in colony forming units per gram (CFU/g),
optionally at least
a 2 log base 10 reduction in CFU/g, optionally at least a 3 log base 10
reduction in CFU/g,
optionally at least a 4 log base 10 reduction in CFU/g of the at least one
type of pathogen,
without substantially causing organoleptic degradation of the food product.
Optionally, after
a span of 6 days from when the product is provided within the interior space
and under
storage conditions of 7 C, at least a I log base 10 reduction in colony
forming units per
gram (CFU/g), optionally at least a 2 log base 10 reduction in CFU/g,
optionally at least a 3
log base 10 reduction in CFU/g, optionally at least a 4 log base 10 reduction
in CFU/g of the
at least one type of pathogen, without substantially causing organoleptic
degradation of the
food product. Optionally, after a span of 10 days from when the product is
provided within
the interior space and under storage conditions of 7 C, at least a I log base
10 reduction in
colony forming units per gram (CFU/g), optionally at least a 2 log base 10
reduction in
CFU/g, optionally at least a 3 log base 10 reduction in CFU/g, optionally at
least a 4 log base
reduction in CFU/g of the at least one type of pathogen, without substantially
causing
organoleptic degradation of the food product. Optionally, after a span of 13
days from when
the product is provided within the interior space and under storage conditions
of 7 C, at
least a 1 log base 10 reduction in colony forming units per gram (CFU/g),
optionally at least
a 2 log base 10 reduction in colony forming units per gram (CFU/g), optionally
at least a 3
log base 10 reduction in CFU/g, optionally at least a 4 log base 10 reduction
in CFU/g of the
at least one type of pathogen, without substantially causing organoleptic
degradation of the
food product. Such organoleptic degradation may include bleaching or other
discoloration
of the food product, as perceived by an ordinary consumer without special
detection
equipment.
101011 Optionally, according to any embodiment, 700-950 mg of the
antimicrobial releasing
agent is effective when used in a IL container having 1.25 lbs of tomatoes
stored therein. It
is contemplated that proportional adjustment of the mass of antimicrobial
releasing agent
26
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may be done according to changes in container volume and amount/type of
contents.
Applications of Invention for Non-Edible Goods
101021 In another aspect, the invention is directed to use of entrained
polymers comprising
antimicrobial agents for use outside of food preservation applications. For
example, the
solutions disclosed herein may be adapted for use in sterilization of
disposable medical
devices, i.e., to reduce the bioburden of such devices when they are packaged.
The primary
difference between preservation of fresh food and medical devices is shelf
life. Preservation
of fresh food implicates a shelf life measured in days or weeks while
maintaining sterility of
packaged medical devices requires a shelf life measured in months or years.
Accordingly,
the release profile over time for one application versus the other will
necessarily vary.
Performance of Entrained Polymer
[0103] The performance of the entrained polymer of the current invention may
be directly
evaluated. The release of the C102 gas is triggered and initiated upon
exposure to moisture,
and the concentration of the released C102 gas in the headspace is measured
over a period.
Typically, the following two methods are used.
Method One.
[0104] A 2 g piece of the entrained polymer, for example, as a film, is placed
in a 2.1 L
mason jar as the testing chamber. In the mason jar is placed a piece of filter
paper (110 mm
diameter, Whatman, Cat # 1001-110) saturated with 1 mL purified water. Care is
taken so
that the film is placed where not in direct contact with the filter paper or
the water thereon.
The mason jar is sealed immediately with a lid. An environmental detectors (BW
GasAlert
C102) is then connected to and is in fluid communication with the headspace
air via two ports
in the lid. A gas transport line including an output line and a return line
diverted the air in
the headspace to the portable C102 gas analyzer before being returned. The
C102
concentration is monitored.
Method Two
[0105] Method Two is identical to Method One in all aspects other than using a
sponge (1'
x x 1/2')
instead of filter paper, and 10 mL water instead of 1 mL of water. Water (10
inL)
is added to the sponge and is completely absorbed in the sponge to give no
free water visibly.
Method Two is used to induce a steeper decline of the C102 concentration due
to the larger
27
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amount of water in the chamber. The larger amount of free water available also
reduces the
concentration of the released C102 gas in the headspace.
101061 Unless otherwise specified, the concentration of the released C102 gas
referred to
herein throughout is normalized to per gram of film, assuming the
concentration of the
released C102 gas is directly proportional to the amount of the entrained
polymer film.
101071 In one aspect, when evaluated using Method One or Method Two, the
current
invention provides an entrained polymer that provides C102 from 3 ppm to 1000
ppm,
optionally 3 ppm to 800 ppm, optionally 3 ppm to 600 ppm, optionally 3 ppm to
500 ppm,
optionally 3 ppm to 300 ppm, optionally 3 ppm to 200 ppm, optionally 3 ppm to
100 ppm,
optionally 3 ppm to 50 ppm, optionally 10 ppm to 1000 ppm, optionally 10 ppm
to 800 ppm,
optionally 10 ppm to 600 ppm, optionally 10 ppm to 500 ppm, optionally 10 ppm
to 300
ppm, optionally 10 ppm to 200 ppm, optionally 10 ppm to 100 ppm, optionally 10
ppm to
50 ppm, optionally 20 ppm to 1000 ppm, optionally 20 ppm to 800 ppm,
optionally 20 ppm
to 600 ppm, optionally 20 ppm to 500 ppm, optionally 20 ppm to 300 ppm,
optionally 20
ppm to 200 ppm, optionally 20 ppm to 100 ppm, optionally 20 ppm to 50 ppm,
optionally
30 ppm to 1000 ppm, optionally 30 ppm to 800 ppm, optionally 30 ppm to 600
ppm,
optionally 30 ppm to 500 ppm, optionally 30 ppm to 300 ppm, optionally 30 ppm
to 200
ppm, optionally 30 ppm to 100 ppm, optionally 30 ppm to 50 ppm, optionally 40
ppm to
1000 ppm, optionally 40 ppm to 800 ppm, optionally 40 ppm to 600 ppm,
optionally 40 ppm
to 500 ppm, optionally 40 ppm to 300 ppm, optionally 40 ppm to 200 ppm,
optionally 40
ppm to 100 ppm, optionally 40 ppm to 50 ppm, optionally 60 ppm to 1000 ppm,
optionally
60 ppm to 800 ppm, optionally 60 ppm to 600 ppm, optionally 60 ppm to 500 ppm,
optionally
60 ppm to 300 ppm, optionally 60 ppm to 200 ppm, optionally 60 ppm to 100 ppm,
optionally
100 ppm to 1000 ppm, optionally 100 ppm to 800 ppm, optionally 100 ppm to 600
ppm,
optionally 100 ppm to 500 ppm, optionally 100 ppm to 300 ppm, optionally 100
ppm to 200
ppm, optionally 150 ppm to 1000 ppm, optionally 150 ppm to 800 ppm, optionally
150 ppm
to 600 ppm, optionally 150 ppm to 500 ppm, optionally 150 ppm to 300 ppm,
optionally 150
ppm to 200 ppm, optionally 200 ppm to 1000 ppm, optionally 200 ppm to 800 ppm,
optionally 200 ppm to 600 ppm, optionally 200 ppm to 500 ppm, optionally 200
ppm to 300
ppm.
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[0108j In one aspect, when evaluated using Method One or Method Two, the
current
invention provides an entrained polymer that normalized to a gram of entrained
polymer
provides at least 3 ppm of C102 1 hour after initiation, optionally, at least
10 ppm of C102 1
hour after initiation, optionally, at least 50 ppm of C102 1 hour after
initiation, optionally, at
least 100 ppm of C102 1 hour after initiation, optionally, at least 150 ppm of
C102 1 hour
after initiation, optionally, at least 300 ppm of C102 1 hour after
initiation.
101091 In one aspect, evaluated using Method One or Method Two, the current
invention
provides an entrained polymer that on a per gram of the entrained polymer
basis provides at
least 3 ppm of C102 5 hours after initiation, optionally, at least 10 ppm of
C102 5 hours after
initiation, optionally, at least 50 ppm of C102 5 hours after initiation,
optionally, at least 100
ppm of C102 5 hours after initiation, optionally, at least 150 ppm of C102 5
hours after
initiation, optionally, at least 300 ppm of C102 5 hours after initiation.
101101 In one aspect, evaluated using Method One or Method Two, the current
invention
provides an entrained polymer that on a per gram of the entrained polymer
basis provides at
least 3 ppm of C102 12 hours after initiation, optionally, at least 10 ppm of
C102 12 hours
after initiation, optionally, at least 50 ppm of C102 12 hours after
initiation, optionally, at
least 100 ppm of C102 12 hours after initiation, optionally, at least 150 ppm
of C102 12 hours
after initiation, optionally, at least 300 ppm of C102 12 hours after
initiation.
10111] In one aspect, evaluated using Method One or Method Two, the current
invention
provides an entrained polymer that on a per gram of the entrained polymer
basis provides at
least 3 ppm of C102 24 hours after initiation, optionally at least 10 ppm of
C102 24 hours
after initiation, optionally, at least 50 ppm of C10224 hours after
initiation, optionally at least
100 ppm of C102 24 hours after initiation, optionally, at least 150 ppm of
C10224 hours after
initiation, optionally at least 300 ppm of C102 24 hours after initiation.
101121 In another aspect, evaluated using Method One or Method Two, the
current invention
provides an entrained polymer that on a per gram of the entrained polymer
basis once reaches
at least 3 ppm of CI02, maintains the concentration of the C102 gas at at
least 3 ppm for at
least 12 hours, optionally for at least 24 hours, optionally for at least 36
hours, optionally for
at least 48 hours, optionally for at least 60 hours, optionally for at least
72 hours, optionally
for at least 84 hours, optionally for at least 96 hours.
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[0113] In another aspect, evaluated using Method One or Method Two, the
current invention
provides an entrained polymer that on a per gram of the entrained polymer
basis once reaches
at least 10 ppm of C102, maintains the concentration of the C102 gas at at
least 10 ppm for
at least 6 hours, optionally for at least 12 hours, optionally for at least 24
hours, optionally
for at least 36 hours, optionally for at least 48 hours, optionally for at
least 60 hours,
optionally for at least 72 hours, optionally for at least 84 hours, optionally
for at least 96
hours.
[0114] In another aspect, evaluated using Method One or Method Two, the
current invention
provides an entrained polymer that on a per gram of the entrained polymer
basis once reaches
at least 30 ppm of C102 , maintains the concentration of the C102 gas at at
least 30 ppm for
at least 6 hours, optionally for at least 12 hours, optionally for at least 24
hours, optionally
for at least 36 hours, optionally for at least 48 hours, optionally for at
least 60 hours,
optionally for at least 72 hours, optionally for at least 84 hours, optionally
for at least 96
hours.
[0115] In another aspect, evaluated using Method One or Method Two, the
current invention
provides an entrained polymer that on a per gram of the entrained polymer
basis once reaches
at least 60 ppm of C102, maintains the concentration of the C102 gas at at
least 60 ppm for
at least 6 hours, optionally for at least 12 hours, optionally for at least 24
hours, optionally
for at least 36 hours, optionally for at least 48 hours, optionally for at
least 60 hours,
optionally for at least 72 hours, optionally for at least 84 hours, optionally
for at least 96
hours.
[0116] In another aspect, evaluated using Method One or Method Two, the
current invention
provides an entrained polymer that on a per gram of the entrained polymer
basis once reaches
at least 80 ppm of C102 , maintains the concentration of the C102 gas at at
least 80 ppm for
at least 6 hours, optionally for at least 12 hours, optionally for at least 24
hours, optionally
for at least 36 hours, optionally for at least 48 hours, optionally for at
least 60 hours,
optionally for at least 72 hours, optionally for at least 84 hours, optionally
for at least 96
hours.
[0117] The invention provides an entrained polymer with varying features, such
as a high
peak concentration of the released C102 gas (for example, X-2719 through X-
2723), a quick
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release (for example, X-2706, X-2702, X-2696 through X-2699), and a sustained
release (for
example, X-2719 through X-2723, X-2715, X-2713, X-2712, and X-2690). The
invention
provides an entrained polymer with the user's desired release properties by
varying the base
polymer, channeling agent, releasing agent, and the weight proportions.
[0118] The entrained polymer of the current invention also enables the CIO2
gas released in
a manner that after the initial release to effectuate antimicrobial effects
produces no
detectable headspace C102 gas. Further, no detectable levels of known C102
degradants
(chlorite or chlorate) upon reaction with water or upon light exposure except
for chloride.
For example, in water, chlorine dioxide reacts quickly to form the very
reactive chlorite ions
which in turn are broken down to form chloride ions. In water, C102 could
disproportionate
to chlorite and chlorate. The entrained polymer of the current invention is
capable of leaving
no foot prints except for chloride. The phenomenon is particularly pronounced
when the
entrained polymer is used on a food product that provides an active redox
environment. For
example, tomatoes, oranges, apples, strawberries, and cantaloupe.
[0119] Without being bound to this theory, based on tests, observations and
analysis, it is
surmised that a two phase C102 gas releasing entrained polymer (without
channeling agent)
would provide insufficient peak and/or sustained concentration within a
container headspace
to provide desirable commercial efficacy. In other words, on a comparative
weight basis,
the two phase material would not appear to inhibit or prevent the growth of
microbes and/or
to kill microbes in or on a food product stored within the container, at least
to practical levels.
For example, the three phase (with channeling agent) entrained polymer
according the
disclosed concept may provide a peak and headspace concentration of C102 gas
to effectuate,
after a span of 2 days from when the product is provided within the interior
space and under
storage conditions of 7 C, at least a 1 log base 10 reduction in colony
forming units per
gram (CFU/g). It is surmised that such efficacy would not be readily
achievable with a two
phase material.
Recitation of Exemplary Embodiments
[0120] The following exemplary embodiments further describe optional aspects
of the
invention and are part of this Specification. These exemplary embodiments are
set forth in
a format substantially akin to claims (each with a numerical designation
followed by a letter
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CA 3043566 2019-06-07
designation), although they are not technically claims of the present
application. The
following exemplary embodiments refer to each other in dependent relationships
as
"embodiments" instead of "claims."
101211 1A. An entrained polymer comprising:
a. a base polymer;
b. a chlorine dioxide gas releasing agent; and
c. a channeling agent,
wherein the entrained polymer features channels though the entrained polymer
formed of the
channeling agent,
wherein the chlorine dioxide gas releasing agent comprises a chlorite salt,
and wherein the entrained polymer on a per gram basis releases the chlorine
dioxide gas in
a concentration of 3 ppm to 1000 ppm, optionally 10 ppm to 1000 ppm,
optionally 30 ppm
to 1000 ppm, optionally 60 ppm to 1000 ppm, optionally 100 ppm to 1000 ppm,
optionally
ppm to 800 ppm, optionally 30 ppm to 600 ppm, optionally 60 ppm to 600 ppm,
optionally
100 ppm to 500 ppm, wherein chlorine dioxide gas release is initiated and the
concentration
of the chlorine dioxide gas is measured using Method One or Method Two.
101221 2A. The entrained polymer of claim 1A, wherein the entrained polymer
releases
the chlorine dioxide gas in a concentration of at least 3 ppm, optionally at
least 10 ppm,
optionally at least 30 ppm, optionally at least 50 ppm, optionally at least
100 ppm, optionally
at least 150 ppm, or optionally at least 300 ppm, I hour after initiation.
101231 3A. The entrained polymer of IA or 2A, wherein the entrained polymer
releases
the chlorine dioxide gas in a concentration of at least 3 ppm, optionally at
least 10 ppm,
optionally at least 30 ppm, optionally at least 50 ppm, optionally at least
100 ppm, optionally
at least 150 ppm, or optionally at least 300 ppm, 5 hours after initiation.
[01241 4A. The entrained polymer of any of embodiments IA to 3A, wherein
the
entrained polymer releases the chlorine dioxide gas in a concentration of at
least 3 ppm,
optionally at least 10 ppm, optionally at least 30 ppm, optionally at least 50
ppm, optionally
at least 100 ppm, optionally at least 150 ppm, or optionally at least 300 ppm,
12 hours after
initiation.
101251 5A. The entrained polymer of any of embodiments IA to 4A, wherein
the
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entrained polymer releases the chlorine dioxide gas in a concentration of at
least 3 ppm,
optionally at least 10 ppm, optionally at least 30 ppm, optionally at least 50
ppm, optionally
at least 100 ppm, optionally at least 150 ppm, or optionally at least 300 ppm,
24 hours after
initiation.
[0126] 6A. .. The entrained polymer of any of embodiments IA to 5A, wherein
after the
concentration of the chlorine dioxide gas reaches at least 3 ppm, the
concentration is
maintained for at least 12 hours, optionally for at least 24 hours, optionally
for at least 36
hours, optionally for at least 48 hours, optionally for at least 60 hours,
optionally for at least
72 hours, optionally for at least 84 hours, optionally for at least 96 hours.
[0127] 7A. The entrained polymer of any of embodiments IA to 6A, wherein
after the
chlorine dioxide gas reaches a concentration of at least 10 ppm, maintains the
concentration
for at least 12 hours, optionally for at least 24 hours, optionally for at
least 36 hours,
optionally for at least 48 hours, optionally for at least 60 hours, optionally
for at least 72
hours, optionally for at least 84 hours, optionally for at least 96 hours.
[0128] 8A. The entrained polymer of any of embodiments IA to 7A, wherein
after the
chlorine dioxide gas reaches a concentration of at least 30 ppm, maintains the
concentration
for at least 12 hours, optionally for at least 24 hours, optionally for at
least 36 hours,
optionally for at least 48 hours, optionally for at least 60 hours, optionally
for at least 72
hours, optionally for at least 84 hours, optionally for at least 96 hours.
[0129] 9A. The entrained polymer of any of embodiments IA to 8A, wherein
after the
chlorine dioxide gas reaches a concentration of at least 50 ppm, maintains the
concentration
for at least 12 hours, optionally for at least 24 hours, optionally for at
least 36 hours,
optionally for at least 48 hours, optionally for at least 60 hours, optionally
for at least 72
hours, optionally for at least 84 hours, optionally for at least 96 hours.
101301 10A. The entrained polymer of any of embodiments lA to 9A, wherein the
chlorine
dioxide gas releasing agent is from 10% to 80%, optionally 30% to 70%,
optionally 30% to
60%, optionally 30% to 50%, optionally from 35% to 70%, optionally from 35% to
60%,
optionally from 35% to 55%, optionally from 35% to 50%, optionally 40% to 70%,
optionally from 40% to 60%, optionally from 40% to 50%, optionally from 45% to
60%,
optionally from 50% to 60% by weight of the entrained polymer.
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101311 I 1A. The entrained polymer of any of embodiments 1A to 10A, wherein
the
channeling agent may be provided in from 1% to 16%, optionally from 1% to 14%,
optionally from 1% to 12%, optionally from 1% to 10%, optionally from 1% to
8%,
optionally from 1% to 6%, optionally from 1% to 5%, optionally from 1% to 4%,
preferably
from 2% to 16%, optionally from 2% to 14%, optionally from 2% to 12%,
optionally from
2% to 10%, optionally from 2% to 8%, optionally from 2% to 6%, optionally from
2% to
5%, optionally from 2% to 4%, optionally from 4% to 12%, optionally from 4% to
10%,
optionally from 4% to 8%, optionally from 4% to 6%, optionally from 4% to 5%,
optionally
from 6% to 12%, optionally from 6% to 10%, optionally from 6% to 8%,
optionally from
8% to 12%, optionally from 8% to 10% by weight of the entrained polymer.
[0132] 12A. The entrained polymer of any of embodiments lA to 11A, wherein the
base
polymer may range from 10% to 70%, optionally from 10% to 60%, optionally from
10% to
50%, optionally from 10% to 40%, optionally from 20% to 60%, optionally from
30% to
70%, optionally from 30% to 60%, from 30% to 50%, optionally from 40% to 70%,
optionally from 40% to 60%, from 40% to 50% by weight of the total
composition.
[0133] 13A. The entrained polymer of any of embodiments lA to 12A, wherein the
at least
one entrained polymer is provided as a film having a thickness of from 0.1 mm
to 1.0
mm, preferably from 0.2 mm to 0.6mm, optionally about 0.3 mm.
[0134] 14A. The entrained polymer of any of embodiments IA to 13A, wherein the
channeling agent is a polyglycol, ethylene-vinyl alcohol (EVOH), polyvinyl
alcohol
(PVOH), glycerin polyamine, polyurethane, polycarboxylic acid, a propylene
oxide
polymerisate-monobutyl ether, a propylene oxide polymerisate monobutyl ether,
propylene
oxide polymerisate, ethylene vinyl acetate, nylon 6, nylon 66,
vinylpyrrolidone-vinyl acetate
copolymer 60/40 (PVPVA 64), or a combination thereof.
101351 15A. The entrained polymer of any of embodiments IA to 13A, wherein the
channeling agent is a polyglycol, vinylpyrrolidone-vinyl acetate copolymer
60/40 (PVPVA
64), or a combination thereof
101361 16A. The entrained polymer of any of embodiments IA to 15A, wherein the
chlorine dioxide gas releasing agent further comprises a catalyst and a
moisture trigger.
101371 17A. The entrained polymer of any of embodiments IA to 16A, wherein the
base
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polymer is thermoplastic polymers, e.g., polyolefins such as polypropylene and
polyethylene, polyisoprene, polybutadiene, polybutene, polysiloxane,
polycarbonates,
polyamides, ethylene-vinyl acetate copolymers, ethylene- methacrylate
copolymer,
poly(vinyl chloride), polystyrene, polyesters, polyanhydrides,
polyacrylonitrile,
polysulfones, polyacrylic ester, acrylic, polyurethane and polyacetal, or
copolymers or
mixtures thereof.
101381 18A. The entrained polymer of any of embodiments lA to 17A, wherein the
base
polymer is 10% to 70%, optionally from 10% to 60%, optionally from 10% to 50%,
optionally from 10% to 40%, optionally from 30% to 70%, optionally from 30% to
60%,
from 30% to 50%, optionally from 40% to 70%, optionally from 40% to 60%, from
40% to
50% by weight of the entrained polymer.
[0139] 19A. The entrained polymer of any of embodiments lA to 18A, wherein the
chlorine dioxide releasing agent is 10% to 80%, optionally 30% to 70%,
optionally 30% to
60%, optionally 30% to 50%, optionally from 35% to 70%, optionally from 35% to
60%,
optionally from 35% to 55%, optionally from 35% to 50%, optionally 40% to 70%,
preferably from 40% to 60%, optionally from 40% to 50%, optionally from 45% to
60%,
optionally from 50% to 60% by weight of the entrained polymer.
[0140] 20A. The entrained polymer of any of embodiments lA to 19A, wherein the
channeling agent is 1% to 16%, optionally 1% to 14%, optionally 1% to 12%,
optionally
from 1% to 10%, optionally from 1% to 8%, optionally from 1% to 6%, optionally
from 1%
to 5%, optionally from 1% to 4%, optionally from 2% to 16%, optionally from 2%
to 14%,
optionally from 2% to 12%, optionally from 2% to 10%, optionally from 2% to
8%,
optionally from 2% to 6%, optionally from 2% to 5%, optionally from 2% to 4%,
optionally
from 4% to 12%, optionally from 4% to 10%, optionally from 4% to 8%,
optionally from
4% to 6%, optionally from 4% to 5%, optionally from 6% to 12%, optionally from
6% to
10%, optionally from 6% to 8%, optionally from 8% to 12%, optionally from 8%
to 10% by
weight of the entrained polymer
[01411 1B. A package
for inhibiting or preventing growth of microbes and/or for
killing microbes in a closed container, comprising the entrained polymer of
any of
embodiments IA to 16A,
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[0142] 2B. The
package of 1B, wherein a product is provided within an interior space, the
product is contaminated by at least one type of pathogen.
[0143] 3B. The
package of embodiments 1B or 2B, wherein the chlorine dioxide gas in
the headspace is detectable from the time of initiation only up until 16
hours, optionally only
up until 20 hours, optionally only up until 24 hours, optionally only up until
36 hours,
optionally only up until 48 hours (i.e., the CIO2 is undetectable after those
points in time).
[0144] IC. A method
for inhibiting or preventing the growth of microbes and/or for
killing microbes in a container, the method comprising providing the entrained
polymer of
any of embodiments IA to 16A, in an interior space of the container.
[0145] ID. A method
for inhibiting or preventing the growth of microbes and/or for
killing microbes in a closed container, the method comprising:
a. providing a closed container defining an interior space therein;
b. providing a food product within the interior space wherein a headspace
is formed
within a volume of the interior space that is not occupied by the food
product; and
c. providing within the interior space an entrained polymer article that is
a monolithic
material comprising a base polymer, a channeling agent and an antimicrobial
releasing
agent comprising a chlorite salt, the antimicrobial releasing agent being
configured to
release chlorine dioxide gas upon activation by moisture that is exuded by the
food product
and/or rests upon the food product;
wherein the chlorine dioxide gas is released into the headspace to achieve a
peak
concentration and sustained concentration within the headspace sufficient to
inhibit or
prevent the growth of microbes and/or for killing microbes in or on the food
product,
optionally wherein the chlorine dioxide gas in the headspace is detectable
from the time of
initiation only up until 16 hours, optionally only up until 20 hours,
optionally only up until
24 hours, optionally only up until 36 hours, optionally only up until 48 hours
(i.e., the C102
is undetectable after those points in time).
101461 1E. A method
of generating chlorine dioxide gas to reach a peak concentration
within an enclosure and then maintain a sustained concentration range within
the enclosure
for a desired time period, the method comprising:
a. providing
an entrained polymer article that is a monolithic material comprising a base
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polymer, a channeling agent and an antimicrobial releasing agent comprising a
chlorite salt,
the antimicrobial releasing agent being configured to release chlorine dioxide
gas upon
activation by moisture; and
b. providing
a source of moisture within the enclosure, optionally a moisture-exuding
food product, within the enclosure, which is configured to activate the
antimicrobial
releasing agent;
wherein peak concentration of at least 6 ppm, optionally at least 10 ppm,
optionally at least
15 ppm, is achieved after 3 hours post-initiation and a concentration of at
least 3ppm or at
least 6 ppm is maintained for up until 16 hours, optionally up until 20 hours,
optionally up
until 24 hours, optionally up until 36 hours post-initiation.
101471 IF. A method
of generating chlorine dioxide gas to reach a peak concentration
within an enclosure and then maintain a sustained concentration range within
the enclosure
for a desired time period, the method comprising:
a. providing an entrained polymer article that is a monolithic material
comprising a base polymer, a channeling agent and an antimicrobial releasing
agent
comprising a chlorite salt, the antimicrobial releasing agent being configured
to release
chlorine dioxide gas upon activation by moisture; and
b. providing a source of moisture within the enclosure which is configured
to
activate the antimicrobial releasing agent;
wherein the entrained polymer on a per gram basis achieves a chlorine dioxide
gas
concentration of at least 25 ppm after 1-3 hours post-initiation and wherein
afterwards the
chlorine dioxide gas concentration remains at at least 25 ppm until at least
12 hours,
optionally at least 24 hours, optionally at least 36 hours, optionally at
least 48 hours,
optionally at least 60 hours, optionally at least 72 hours post-initiation
under either of the
following test conditions:
i. a 2 g piece of the entrained polymer is placed in a 2.1 L mason jar where a
piece
of filter paper saturated with 1 mL water is placed such that the filter paper
is not in direct
contact with the entrained polymer, the mason jar being enclosed by a lid; or
ii. a 2 g piece of the entrained polymer is placed in a 2.1 L mason jar where
a sponge
that has absorbed 10 mL water is placed within the mason jar such that the
sponge is not in
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direct contact with the entrained polymer, the mason jar being enclosed by a
lid.
10148] 2F. The method of embodiment 1F, wherein the entrained polymer on a
per gram
basis achieves a chlorine dioxide gas concentration of at least 50 ppm after 1-
3 hours post-
initiation and wherein afterwards the chlorine dioxide gas concentration
remains at at least
25 ppm until until at least 12 hours, optionally at least 24 hours, optionally
at least 36 hours,
optionally at least 48 hours, optionally at least 60 hours, optionally at
least 72 hours post-
initiation.
101491 3F. .. The method of embodiment 1F or 2F, wherein the entrained polymer
on a per
gram basis achieves a chlorine dioxide gas concentration of at least 100 ppm
after 1-3 hours
post-initiation and wherein afterwards the chlorine dioxide gas concentration
remains at at
least 25 ppm until at least 12 hours, optionally at least 24 hours, optionally
at least 36 hours,
optionally at least 48 hours, optionally at least 60 hours, optionally at
least 72 hours post-
initiation.
101501 1G. .. A method of generating chlorine dioxide gas to reach a peak
concentration
within an enclosure and then maintain a sustained concentration range within
the enclosure
for a desired time period, the method comprising:
a. providing an entrained polymer article that is a monolithic material
comprising a base polymer, a channeling agent and an antimicrobial releasing
agent
comprising a chlorite salt, the antimicrobial releasing agent being configured
to release
chlorine dioxide gas upon activation by moisture; and
b. providing a source of moisture within the enclosure which is configured
to
activate the antimicrobial releasing agent;
wherein the entrained polymer on a per gram basis achieves a chlorine dioxide
gas
concentration of at least 25 ppm after 3-6 hours post-initiation and wherein
afterwards the
chlorine dioxide gas concentration remains at at least 25 ppm until at least
12 hours,
optionally at least 24 hours, optionally at least 36 hours, optionally at
least 48 hours,
optionally at least 60 hours, optionally at least 72 hours post-initiation
under either of the
following test conditions:
i. a 2 g piece of the entrained polymer is placed in a 2.1 L mason jar where a
piece
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of filter paper saturated with I mL water is placed such that the filter paper
is not in direct
contact with the entrained polymer, the mason jar being enclosed by a lid; or
ii. a 2 g piece of the entrained polymer is placed in a 2.1 L mason jar where
a sponge
that has absorbed 10 mL water is placed within the mason jar such that the
sponge is not in
direct contact with the entrained polymer, the mason jar being enclosed by a
lid.
[0151] 2G. The method of embodiment 1G, wherein the entrained polymer on a
per gram
basis achieves a chlorine dioxide gas concentration of at least 50 ppm after 3-
6 hours post-
initiation and wherein afterwards the chlorine dioxide gas concentration
remains at at least
25 ppm until at least 12 hours, optionally at least 24 hours, optionally at
least 36 hours,
optionally at least 48 hours, optionally at least 60 hours, optionally at
least 72 hours post-
initiation.
[0152] 3G. The method of embodiment 1G or 2G, wherein the entrained polymer on
a
per gram basis achieves a chlorine dioxide gas concentration of at least 100
ppm after 3-6
hours post-initiation and wherein afterwards the chlorine dioxide gas
concentration remains
at at least 25 ppm until until at least 12 hours, optionally at least 24
hours, optionally at least
36 hours, optionally at least 48 hours, optionally at least 60 hours,
optionally at least 72 hours
post-initiation.
[0153] 4A. A method for inhibiting or preventing the growth of microbes
and/or for
filling microbes in a closed container, the method comprising:
a. providing a closed container defining an interior space therein;
b. providing a food product within the interior space wherein a headspace is
formed
within a volume of the interior space that is not occupied by the food
product; and
c. providing within the interior space an entrained polymer article that is a
monolithic
material comprising a base polymer, a channeling agent and an antimicrobial
releasing agent
comprising a chlorite salt, the antimicrobial releasing agent being configured
to release
chlorine dioxide gas upon activation by moisture that is exuded by the food
product and/or
rests upon the food product;
wherein the chlorine dioxide gas is released into the headspace to achieve a
peak
concentration and sustained concentration within the headspace sufficient to
inhibit or
39
CA 3043566 2019-06-07
prevent the growth of microbes and/or for killing microbes in or on the food
product.
101541 The invention will be illustrated in more detail with reference to the
following
Examples, but it should be understood that the present invention is not deemed
to be limited
thereto.
EXAMPLES
Example 1 ¨ Controlling Release of C102 Gas
[0155] A storage temperature of 7 C was chosen to replicate a storage
temperature that is
slightly elevated above ideal storage temperature (or to stimulate an
inadvertent spike in
temperature during storage, e.g., when refrigeration equipment breaks down for
a few hours).
Three packages similar to that shown in FIG. 7 were utilized in this
experiment. All three
included antimicrobial entrained polymer film sections placed substantially as
shown in FIG.
7. The film was a three phase entrained polymer film including an
antimicrobial releasing
agent in the form of a powdered mixture comprising sodium chlorite (which
produces
chlorine dioxide gas), sulfuric acid clay (as a catalyst) and calcium chloride
(as a humidity
trigger). This powdered mixture is sold commercially by BASF under the name
ASEPTROL
and is described above.
[0156] The formulation for the film itself was a three phase formulation
including 50% by
weight of the aforementioned antimicrobial releasing agent in the form of the
powdered
mixture, 38% by weight ethyl vinyl acetate (EVA) as a base polymer and 12% by
weight
polyethylene glycol (PEG) as a channeling agent. This film formulation is
described herein
as X2597 and is considered one exemplary non-limiting embodiment of an
entrained
polymer according to an aspect of the disclosed concept. As described above,
the
antimicrobial releasing agent is triggered by moisture to release chlorine
dioxide (C102) gas
as the released antimicrobial material. The film, as between the three
packages, was the same
formulation and dimensions. However, two of the films had external layers to
control
moisture uptake and one had no such layers. The film in Package A was
sandwiched between
coextruded layers of LDPE that were about 0.02 mm thick. The film in Package B
was
sandwiched between coextruded layers of LDPE that were about 0.04 mm thick.
The film in
Package C (the control) had no such polymer layers on either side of the film.
CA 3043566 2019-06-07
[0157] The C102 levels in the packages were measured for 13 days with
detection sensors
calibrated for the desired concentration known to have an antimicrobial effect
on most
organisms. Results were as follows (values presented in ppm concentration of
C102).
Day Package A Package B Package C
1 24 17 34
2 27 22 43
3 28 21 29
4 27 21 27
28 20 26
6 29 20 25
7 26 21 18
8 21 21 12
9 17 19 9
13 17 4
11 11 16 4
12 8 13 4
13 6 11 4
101581 This Example demonstrates that Package B had the steadiest and most
consistent
release profile, attributable to the thicker polymer liner sandwiching the
antimicrobial film,
which controlled moisture uptake into the film. The release profile of Package
B may be
desirable for certain applications, for example, where the food product exudes
a relatively
modest amount of moisture, such as broccoli.
Example 2 ¨ Geotrichum Growth Testing
101591 A common cause of rejects for quality of tomatoes is Geotrichum
candidum, a yeast-
like mold that grows as a white fuzz. In this example, sliced tomatoes
deliberately tainted
with G. candidum were packaged and subjected to testing. A storage temperature
of 7 C
was chosen to replicate a storage temperature that is slightly elevated above
ideal storage
temperature (or to stimulate an inadvertent spike in temperature during
storage, e.g., when
refrigeration equipment breaks down for a few hours).
101601 A package similar to that shown in FIG. 7, with the C102-releasing
antimicrobial film
placed towards the top of the package, was used to store the contaminated
sliced tomatoes.
41
CA 3043566 2019-06-07
A second package, otherwise identical to the first except without the
antimicrobial film, was
used to store the contaminated sliced tomatoes. The results are provided on
the graphs shown
in FIGS. 8A and 8B. The results show conclusively that the antimicrobial film
significantly
inhibited growth of Geotrichum on the sliced tomatoes compared to the package
without the
film. In the package without the antimicrobial film, proliferation of
Geotrichum on the sliced
tomatoes was readily apparent to the naked eye. By contrast, the sliced
tomatoes in the
package with the entrained polymer C102-releasing antimicrobial film appeared
fresh, with
no visible signs of Geotrichum growth. This is further notable given the
suboptimal 7 C
storage conditions for the 14-day test.
[0161] It should be understood that examples on tomatoes were merely exemplary
and that
other produce and fresh foods (e.g., meat) may be used in accordance with the
invention. It
should be further understood that while chlorine dioxide is one preferred
released
antimicrobial material, other released antimicrobial materials are within the
scope of the
invention and may be preferred for other applications.
Example 3 - Antimicrobial Film Location Testing
101621 Entrained polymer film (X2597 film, described above) was placed in
the
headspace of a tray at various height positions on the sidewalls to test the
effectiveness
of various antimicrobial film locations/positions, as well as various sampling
locations. The
abbreviation "MCT" as used herein refers to Maxwell Chase Technologies, LLC of
Atlanta,
GA. The abbreviation "FPT" refers to FRESH-R-PAX trays of Maxwell Chase
Technologies, LLC.
101631 The following materials were used in this example:
16 - 1g X2597 Film Strips Lot #02116A030A (CSP Technologies ¨Auburn, AL).
66 Tomatoes (5x5 red tomatoes purchased from grocery store the day of the
experiment).
24 MCT FPT 125D Trays (Maxwell Chase Technologies - Atlanta, GA) having a
bottom
surface and an opposite opening, with four sidewalls extending vertically from
the bottom
surface. The sidewalls had a length of 10" and height of 3 5"8 (measured from
the
bottom surface).
24 plastic holders (Made from cut MCT FPT125D trays.)
4?
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Polypropylene (PP) lidding film approx. 50-gauge oriented polypropylene cast/
I mil.
Cast Polypropylene (0.00152" thick) app. 90cc/100in2/day OTR ,
0.8gm/100in2/day
WVTR (MCT - Atlanta, GA)
MCT-MTS Manual Tray Sealer at 375 F (MCT Atlanta, GA).
SABER Tomato Hand-Slicer 7/32" slices (Prince Castle,Carol Stream, IL).
ATI C16 Portable Gas Analyzer (Analytical Technology Inc. Collegeville, PA).
C102 Sensor #00-1425 1/5 (ATI Collegeville, PA).
C102 Sensor #00-1004 1/5.
C102 Sensor #00-1005 5/200.
C102 Sensor #00-1359 200/2000.
Tempure Scientific Top Mount Laboratory Refrigerator (Model #LP-75-HG-TP)
equipped with a Dixell XR4OCX computer control set at 7C temperature with high
of 8 C
and low of 6 C cooling setting.
2 Sets of CPC #3438400 Quick-Disconnect Valves with compression fittings per
mason
jar (McMaster-Carr (MCM) #5012K122).
Flex GP 70 3/16" ID, 1/4" OD black PVC tubing (MCM #5231K35).
011 Buna-N 0-ring, oil resistant, round profile (MCM #9408K41).
Xacto Knife.
[0164] The MCT
FPT125D (1/4 steam size, deep white polypropylene) trays were
modified as follows. Three holes approximately 8.5 mm wide and 2 cm apart were
made into
the MCT FPT125D trays with an Xacto knife. Edges of the hole were cleaned and
the CPC
valves were screwed into the holes with an o-ring on both sides, and the
compression fitting
tightening down the 2 rings. Both valves were placed with QDV on the outside
of the lid and
container to allow for the automatic closing valves to be on the outside for
sampling
purposes.
[0165] Flex GP 70 3/16" ID, 1/4" OD black PVC tubing(MCM#5231K35) was used on
both intake and outtake ports of the C16 Portable Gas Analyzer, as well as the
other end of
43
CA 3043566 2019-06-07
the CPC #3438400 Quick-Disconnect Valves with compression fittings to connect
to the
trays to sample the headspace in the trays.
[0166] CSP film samples were cut from the same strip of film and same width.
Then, each
sample was weighed to 1.000 g and connected to a sidewall of the tray with a
plastic piece
to hold it in place. There were two samples in each tray, which resulted in 2
g of CSP film
per tray. Each of the samples was connected to a different sidewall of the
tray.
[0167] The tomatoes were sliced using the hand-slicer with the calyx facing
down. The ends
were discarded. About 7 slices of tomatoes were placed on the bottom surface
of each tray.
[0168] The manual sealer was heated to 375 F, and each tray with tomatoes
therein was
placed on the respective sealing plate. Lidding/Sealing film was placed over
the tray, the
sealing handle was pressed down and held for approximately 1-2 seconds to
cover/seal the
tomatoes inside the tray.
[0169] For each of the trays, the C102 release rate was measured in one-
hour intervals
over an 11-hour period. FIG. 9 shows the release of C102 (ppm) corresponding
to various
positions of the CSP film in the tray, i.e., at 0%, 50%, 64%, 79% and 100%
height from the
bottom surface based on total height of the sidewall. These respective heights
are measured
from the midline of the film. FIG. 10 shows the effect of the CSP film height
on headspace
concentration.
[0170] The results indicate that varying the height of the CSP film in the
tray has an
effect on the presence of C102 in the headspace. From the bottom of the tray
(0%) to the
mid-point (50%- approximately 2 inches up the sidewall in this particular non-
limiting
example), there was only a small, e.g., insignificant change in headspace
concentration.
However, from the mid-point to the top of the tray, the increase in height
resulted in a
significant increase in concentration. The concentration doubled from a
position at 64% of
the total height to the top of the tray (100%). The data indicates that in
order to maximize
the headspace concentration of C102 for optimum effectiveness and/or to
minimize the
amount of film required, the placement of the film should be preferably in the
top 20% of
the tray, i.e., positioned at a vertical height that is 80% to 100% of the
total height of the
sidewall measured from the bottom surface, and should be placed at least at
64% of the total
44
CA 3043566 2019-06-07
height of the sidewall of the tray.
Example 4¨ Use of Quick Burst Release Profiles to Kill Pathogens
101711 The effectiveness of reducing the level of Listeria monocytogenes, E.
colt, and
Salmonella, was evaluated for CSP C102 film applied to an upper portion of a
tray as
compared to control trays absent of the CSP C102 film.
101721 CSP C102 emitting films, designated formulation X2597 (described
above), at 0.3
mm thickness were used. This formulation was designed to have a fast C102
release profile
and did not use an overlying polyethylene layer to reduce the moisture uptake
rate into the
film. As described above, the X-2597 film is a three phase formulation
including 50% by
weight of antimicrobial releasing agent, 38% by weight ethyl vinyl acetate
(EVA) as a base
polymer and 12% by weight polyethylene glycol (PEG) as a channeling agent.
Trays with
either 4 grams or 3 grams of film per tray were used. The tomatoes in the tray
were each
inoculated with three pathogens, i.e., Listeria monocytogenes, E. Coli and
Salmonella.
101731 The following materials were used in this example.
250 Tomatoes-category 5x5 (extra for waste) (5 cases 50/ cases)
Tomato hand-slicer (Prince Castle)
Manual sealer set at 375 F(Maxwell Chase Tech.)
Polypropylene lidding film Approx. 90 OTR (Maxwell Chase Tech)
Listeria monocytogenes 5 strain cocktail inoculums (Food Isolates)
Salmonella 5 strain cocktail (Food Isolates)
E. colt 0157:H7 5 strain cocktail (Food Isolates)
Sterile Dilution water and tubes
Sterile forceps
Alcohol beaker and flame for sterilizing forceps
Sterile surgical knives
FPT 125D Trays (1/4 steam sized white polypropylene trays) w/ I g C102 film on
each
upper corner
10 FPT 125D Trays (1/4 steam sized white polypropylene trays) w/ 0.75g C102
film on
each upper corner
10 FPT 125D Trays (1/4 steam sized white polypropylene trays) designated -MCT
4 Un-inoculated Trays designated - UN
Refrigerator set at 7 C
564 MOX Plates (60 day 0. 168 days 5, 8, 12) designated - List.
564 XLD plates (60 day 0. 168 days 5, 8, 12) designated -Sal.
564 PCA plates (60 day 0. 168 days 5,8, 12) designated - APC
564 MAC plates (60 day 0. 168 days 5,8, 12) designated - E. coli
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Enrichment broth for corresponding pathogens
Extra plates for streak verification
[0174] Salmonella, Listeria monocytogenes, and E. Colt 0157:H7 5 strain
cocktails were
prepared, mixed and kept overnight. The target was to achieve a 5-log
inoculation of each
9
pathogen on the tomatoes. The inoculated tomatoes had 10 CFU pathogen/ml
inoculum.
Inoculations were plated for verification and initial levels.
[0175] A solution of 200 ppm free chlorine solution was prepared using
lukewarm water.
The slicer was immersed in the solution for 2 min, and then rinsed with tap
water.
[01761 A 200-ppm free chlorine solution was prepared using warm water
(approximately the
same temperature as for the tomatoes). The tomatoes were placed in tap water
first, then the
chlorine solution for 2 minutes, and rinsed with tap water. The tomatoes were
sliced using
the hand-slicer with the calyx facing down. The ends were discarded such that
there were 42
slices packed into each tray (6 tomatoes by 7 slices/tomato).
[0177] Eighteen (18) tomato slices within each tray were spot inoculated with
the
Salmonella, Listeria monocytogenes, and E. Colt (6 each) inoculums to achieve
a triplicate
analysis in each tray. The 18 tomato slices selected were identified by
marking each slice
with a Sharpie adjacent to the area to be inoculated. The inoculum was
vortexed and 10 u 1
of inoculum was quickly withdrawn with a sterile pipette tip and micro
pipetted onto the two
slices marked at the top. This was repeated twice more per tray per pathogen.
[0178] The manual sealer was heated to 375 F. Each tray was placed on the
sealing plate
and the lidding film was pulled over the tray. The sealing handle was
depressed and held in
place for approximately 1-2 seconds. After sealing, each tray was checked to
verify that the
lidding film was fully attached to the tray.
101791 The test trays were analyzed on days 0, 5, 8 and 12. For each tray,
there were a total
of three samples for each pathogen, three pathogens per tray and three APC
(aerobic plate
count) samples were taken from each tray. Each sample consisted of two slices
taken using
sterile forceps. The two slices were weighed into the sterile stomacher bag
(weight was
approximately 40-50 g) and three times the amount of sterile Peptone water was
added. The
tomatoes were stomached at 260 rpm for 1 minute. The necessary dilutions were
then
46
CA 3043566 2019-06-07
prepared (-3) from the homogenate and duplicate spread plated onto the
corresponding PCA,
MOX, SMAC, or XLD plates.
101801 Data was calculated as colony forming units (CFU) per gram. CFU values
were
converted to log values for data analysis. Data was averaged per tray and per
sample type.
The following is a summary of the tests that were conducted on respective
days. The term
"CSP3" refers to trays using 3g of X2597 film and the term "CSP4" refers to
trays using 4g
of X2597 film.
101811 Day 0: 1 MCT tray inoculated w/ 3 Salmonella, 3 E. Coli, 3 Listeria and
3 APC
tests/tray = 12 tests; 1 CSP4 tray inoculated w/ 3 Salmonella, 3 E. Coli, 3
Listeria and 3 APC
tests/tray = 12 tests; 1 CSP3 tray inoculated w/ 3 Salmonella, 3 E. Coli, 3
Listeria and 3 APC
tests/tray = 12 tests; 1 UN tray not inoculated (Negative Control) x 4 tests
(sal,
E.coli,Lm,APC)/tray = 4 tests. Cumulatively, this was a total of 40 tests.
101821 Day 5: 3 MCT tray inoculated w/ 3 Salmonella, 3 E. Coli, 3 Listeria and
3 APC
tests/tray = 36 tests; 3 CSP4 tray inoculated w/ 3 Salmonella, 3 E. Coli, 3
Listeria and 3 APC
tests/tray = 36 tests; 3 CSP3 tray inoculated w/ 3 Salmonella, 3 E. Coli, 3
Listeria and 3 APC
tests/tray = 36 tests; 1 UN tray not inoculated (Negative Control) x 4 tests
(sal,
E.coli,Lm,APC)/tray = 4 tests. Cumulatively, this was a total of 112 tests.
101831 Day 8: 3 MCT tray inoculated w/ 3 Salmonella, 3 E. Coli, 3 Listeria and
3 APC
tests/tray = 36 tests; 3 CSP4 tray inoculated w/ 3 Salmonella, 3 E. Coli, 3
Listeria and 3 APC
tests/tray = 36 tests; 3 CSP3 tray inoculated w/ 3 Salmonella, 3 E. Coli, 3
Listeria and 3 APC
tests/tray = 36 tests; 1 UN tray not inoculated (Negative Control) x 4 tests
(sal,
E.coli,Lm,APC)/tray = 4 tests. Cumulatively, this was a total of 112 tests.
[0184] Day 12: 3 MCT tray inoculated w/ 3 Salmonella, 3 E. Coli, 3 Listeria
and 3 APC
tests/tray = 36 tests; 3 CSP4 tray inoculated w/ 3 Salmonella, 3 E. Coli, 3
Listeria and 3 APC
tests/tray = 36 tests; 3 CSP3 tray inoculated w/ 3 Salmonella, 3 E. Coli, 3
Listeria and 3 APC
tests/tray = 36 tests; 1 UN tray not inoculated (Negative Control) x 4 tests
(sal,
E.coli,Lm,APC)/tray = 4 tests. Cumulatively, this was a total of 112 tests.
101851 In all, this experiment cumulatively included a total of 376 tests (94
Salmonella, 94
E. Coli, 94 Listeria, 94 APC). Results are shown in FIGS. 11-13.
101861 FIG. 11 shows that there was a decline in Salmonella after Day 0 and
stayed in
47
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decline until day 12 for the CSP3 trays, and continued for the CSP4 trays.
Each of these
samples showed a reduction in Salmonella counts of at least 1.8 logs on day 5,
2.5 logs for
day 8, and 3 logs for Day 12 respectively. This demonstrates a 99.9% rcduction
in Salmonella
after 12 days in the CSP trays.
[0187] FIG. 12 shows results for E. coli that are similar to the Salmonella
results. A decline
in E. coli after Day 0 resulted in a reduction of at least 2 logs on day 5, 4
logs on day 8, and
3 logs on day 12. Similar to FIG. 11 for Salmonella, FIG. 12 shows an increase
for the CSP3
tray on Day 12. It was determined that there was a 99.9% reduction in E. coli
after a 12-day
period.
[0188] FIG. 13 shows that the CSP film also reduced Listeria by 1 log over 12
days of shelf
life. This is consistent on every day samples were obtained, and demonstrated
a 90%
reduction of Listeria monocytogenes consistently for 12 days.
[0189] These results demonstrate the effectiveness of the CSP trays (according
to optional
aspects of the invention) with sliced tomatoes over a 12-day storage period to
reduce the
amounts of Salmonella, E. coli, and Listeria inoculated on the tomato slices
and stored at
8 C. This is not a normal storage condition, but it simulates potential abuse
within the cold
chain that is noted in food safety storage practices as being the major cause
of spoilage and
pathogen growth. The use of these trays can contribute to reducing the
potential for
pathogens growth to harmful levels in sliced tomatoes.
Example 5 ¨ Quick Burst Antimicrobial Gas Release Curves
[0190] As described in Example 4, above, trays using 3g or 4g of X2597 film
demonstrated
significant activity in inhibiting pathogenic growth and proliferation over
the testing period.
The film formulations were configured to provide a quick burst release
profile, as discussed
elsewhere in this specification. FIG. 14 provides release curves for the 3g
and 4g versions
that were used in Example 4. FIG. 14 also provides a release curve for trays
that used only
2g of film.
[0191] As FIG. 14 shows, the trays using 4g of film (CSP4) peaked at
approximately 30 ppm
of C102 at about hour 18, while holding above 10 ppm between about hour 6 to
hour 33. The
trays using 3g of film (CSP3) peaked at approximately 23 ppm of C102 at about
hour 15,
48
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while holding above 10 ppm between about hour 6 to hour 33. As stated above in
Example
4, these embodiments provided sufficient headspace concentration to achieve a
desired
microbial kill and did so without bleaching the tomatoes.
101921 FIG. 14 also shows a release curve for trays using 2g of film. As the
curve shows,
that embodiment peaked at approximately 16 ppm of C102 between hours 12 and
18.
However, that curve shows that C102 concentration only held above 10 ppm
between about
hours 8 to 26. In some circumstances, this concentration and release curve may
provide
sufficient antimicrobial effect, but in this instance, this concentration was
not preferred
(albeit is still within the scope of optional aspects of the disclosed
concepts).
Example 6 ¨ Representative Antimicrobial Films of the Invention
101931 Thirty-eight types of antimicrobial film were extruded (0.3 mm in
thickness)
according to the formulations in Tables 1-5 below. The prefix X to each batch
number is
omitted in the tables below. Therefore, a batch number 2719 may also be
referred to as X-
2719.
Table 1. Formulation of films with Batch Numbers 2719-2726.
Batch 2726 2725 2724 2722 2723 2721 2720
2719
Aseptrol 50 50 50 35 50 35 35 35
EVA2528 38 42 45 53 49 57 60 64
PVPVA64 12 8 5 12 1 8 5 1
Table 2. Formulation of films with Batch Numbers 2711-2718.
Batch 2718 2717 2716 2715 2714 2713 2712
2711
Aseptrol 50 50 50 50 35 35 35 35
Exact
3040 38 42 45 49 53 57 60 64
PVPVA64 12 8 5 1 12 8 5 1
Table 3. Formulation of films with Batch Numbers 2703-2708.
Batch 2708 2707 2706 2705 2704 2703
Aseptrol 50 50 35 35 35 35
Santoprene
281-55 45 49 53 57 60 64
Ca rbowax
4000P 5 1 12 8 5 1
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Table 4. Formulation of films with Batch Numbers 2695-2702.
Batch 2702 2701 2700 2699 2698 2697 2696 2695
Aseptrol 50 50 50 50 35 35 35 , 35
EVA2528 38 42 45 49 53 57 60 64
Carbowax
4000P 12 8 5 1 12 8 5 1
Table 5. Formulation of films with Batch Numbers 2687-2694.
Batch 2694 2693 2692 2691 2690 2689 2688 2687
Aseptrol 50 50 50 50 35 35 35 35
Exact 3040 38 42 45 49 53 57 60 64
Carbowax
4000P 12 8 5 1 12 8 5 1
Example 7 Antimicrobial Films with Wide Range of Gas Release Properties
101941 The release of the C102 gas from the films in Example 6 was triggered
and measured
using Method One or Method Two as described above. For example, using Method
One, a
2 g piece of each of the films in Example 6 was placed in a 2.1 L mason jar.
In the mason
jar was placed a piece of filter paper (110 mm diameter, Whatman, Cat # 1001-
110)
containing 1 mL purified water. Care was taken so that the film was not in
direct contact
with the filter paper or the water thereon. The mason jar was sealed
immediately with a lid.
An environmental detectors (BW GasAlert CI02) was connected to and was in
fluid
communication with the headspace air via two ports in the lid. The C102
concentration was
monitored.
101951 The results of the released C102 concentration using Method Two are
tabulated in
Tables 6-11 and plotted in FIG. 15 (corresponding to films in Table 1 and data
in Table 6),
FIG. 16 (corresponding to films in Table 2 and data in Table 7), FIG. 17
(corresponding to
films in Table 3 and data in Table 8 and 9), FIG. 18 (corresponding to films
in Table 4 and
data in Table 10), and FIG. 19 (corresponding to films in Table 5 and data in
Table 11)
respectively.
101961 These examples represent embodiments of the current invention that
provide varying
features, such as a high peak concentration of the released C102 gas (for
example, X-27 I 9
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through X-2723), a quick release (for example, X-2706, X-2702, X-2696 through
X-2699),
and a sustained release (for example, X-2719 through X-2723, X-2715, X-2713, X-
2712,
and X-2690).
101971 The base polymers, channeling agents, and the chlorine dioxide
releasing agents
described above provides an entrained polymer that affords the user a desired
release profile.
[01981 The preferred embodiments can be found in X-2719 through X-2723, X-
2706, X-
2702, X-2695 through X-2699, X-2719 through X-2723, X-2712 through X-2715, and
X-
2689 through X-2692, and the make-up thereof.
51
CA 3043566 2019-06-07
.
.
r)
w
0
0.
w
cri
0, Table 6. Headspace concentration of
released chlorine dioxide.
m
m
o Time
1-,
k0 (hrs) 0.75 1.73 2.77 3.78 4.72 5.70 6.82 7.70 10.68 22.60
28.60 _34.23 46.55 52.60 58.83 70.62 76.58 83.48
1
0
0, 2726 0.5 0.5 0.5 0.5 0.5 0.5 0.5 2.1 2.1 0.5 0.5
0.5 0.5 , 0.5 0.5 0.5 0.5 0.5
1
0 2725 0.5 0.5 0.5 0.5 2 2 2 2 2 2
2 0.5 0.5 0.5 0.5 0.5 0.5 0.5
..4
2724 0.5 2 4 6 8.5 8 10 10 14 14 6
4 2.5 0.5 2 0.5 0.5 0.5
2723 4.7 13 20 64 85 109 139 149 208 242 132 110 109 27 45 25 8.9 11
2722 0.5 5.1 17 28 38 45 57 59 78 80 46 38 35 9.6 16 6.8 2.8 2.8
2721 2 6.7 20 36 48 61 73 81 107
121 74 57 49 15 27 20 10 20
2720 0.5 5.9 20 35 47 57 67 73 97 120 71 59 59 18 34 27 15 23
2719 2.4 3.9 11 20 30 37 46 51 74 125 79 72 77 25 50 46 26 39
IN.) Table 7. Headspace concentration of
released chlorine dioxide.
Time
(hrs)I 0.88 1.88 2.85 3.87 4.83 5.88 6.87 7.80 22.92 28.92 34.92 70.92
2718 0 0 0.5 0.5 0.5 7 2 2
2 2 2 2
2717 0 0.5 2.1 2.8 2.9 2.9 3.1
2.9 2 2 2 2
2716 0.8 15 25 26 28 , 34 34 32
12 6.4 5.9 2.4
2715 0 4.4 9.7 12 15 21 23 24
71 45 43 40
2714 0 0.5 1.5 1.5 0.98 1.9 1.9
2.3 2.5 2.45 2.5 2.5
2713 1.4 7.9 9.6 18 19 19 22 32
83 37 40 38
2712 0 0.96 5.3 8.2 6.8 8.2 12
17 53 33 29 27
2711 0 0 0.99 2.9 3.9 4.26 5.7
8.2 18 8.2 12 20
lAn average of three samples for each time point is reported with the
exception of the last four time points (one sample for each).
=
o
0
Table 8. Headspace concentration of released chlorine dioxide.
cri
Time
0
(hrs) 0.75 1.73 2.77 3.78 4.72 5.70
6.82 7.70 _ 10.7 22.6 28.6 34.2 46.5 52.6 58.8
70.6 76.6 83.4
2706 17 21 47 60 , 63 60 60 58 66
50 19 8 0.5 0.5 0.5 0.5 0.5 0.5
0
2705 2.5 2 2.5 2.5 4 2.5 2.5 2.5 2.5
4 2.5 4 2.5 2 2.5 2 0.5 2
0
2704 4.4 4 8 8 8 8 8 8 10 15 12 12 10 4 8 4 2 4
2703 8 6 14 16 19 20 22 22 24
24 15 12 11 6 8.5 10 8 8
Table 9. Headspace concentration of released chlorine dioxide.
Time
(hrs)' 1 2 3 4 5 6 7 8
23 28 35 71
2707 0 0 0.33 0.49 0.49
1.9 1.9 1.9 1.9 1.9 1.9 1.9
2708 0 0 0.49 0.49 0.49
1.9 1.9 1.4 1.9 1.9 1.9 1.9
lAn average of three samples for each time point is reported with the
exception of the last four time points (one sample for each).
Table 10. Headspace concentration of released chlorine dioxide.
Time
(hrs) 0.87 1.85 2.87 3.90 4.83 5.80 6.93 7.82 10.82 22.72 28.72 34.37 46.67
52.72 58.95 70.73 76.72 83.60
2702 16 72 188 241 221 172 128 92 51 2 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5
2701 3.9 7.9 11 12 9.9 6 4 2 2 0.5
0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5
2700 2 2.5 2 2 2.5 2.5 2.5 2.5 2.5 2 2 2 2 2 2 2 0.5 0.5
2699 15 25 43 89 109 114 116
110 102 . 57 24 29 24 12 18 14 6 6
2698 89 193 238 416 425 381 360 318 268 101 16 2 0.5 0.5 2 0.5 0.5 0.5
2697 ' 31 60 100 200 231 234 242 232 228
183 167 62 27 11 22 16 10 11
o
0 Time
(hrs) 0.87 1.85 2.87 3.90 4.83 5.80 6.93 7.82 10.82 22.72 28.72 34.37 46.67
52.72 58.95 70.73 76.72 83.60
cri
2696 15 21 42 76 78 72 66 56 45 15 6.4 6.4
4 2 4 _ 2 2 2
2695 2 6 8.6 32 47 57 65 67 76 90 43 45 7.1 19 35 25 21 20
0
0
Table 11. Headspace concentration of released chlorine dioxide.
0
Time
(hrs) 1.00 2.00 3.02 4.03 4.98 5.97 7.08 7.98 10.98 22.87 28.85 34.52 46.82 _
52.87 59.10 70.90 76.87 83.75
2694 2 2 2 2.5 2.5 2.5 2 2 2 2
0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5
2693 0.5 4 4.56 8 10 10 10 11 12 14 8
8 _ 4 2 2 0.5 0.5 0.5
2692 2 2.5 2.5 10 12 15 19 20 27 38
15 14 8 2.5 4 2 0.5 0.5
2691 0.5 2 2 4 6 10 12 15 27 74 49 51 49 18 23 14 8 8
2690 3 20 23 44 49 54 55 55 66 101 47 65 98 29 40 27 12 14
2689 0.5 2 4 8 10 11 14
14 20 1 31 15 18 27 6.5 11 6 2.5 2.5
2688 0.5 0 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5
2687 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 2 8 4
6 10 6 6 4 2 6
Example 8 ¨ Superior Release Results of Invention
101991 Films X-2596 and X-2597 were extruded according to the formulation
below. Note
that X-2597 and X-2702 share the same composition.
X-2596 Englehard Aseptrol 7.05 50%
EVA 2528 50%
X-2597 Englehard Aseptrol 7.05 50%
Carbowax 4000P 12%
EVA 2528 38%
[0200] The release properties of Films X-2596 and X-2597 were evaluated using
Method
One described above. The released C102 concentration for each is shown in the
table below
(normalized to per gram of film) and is plotted in FIG. 20.
Time (hrs) 1.00 2.00 3.00 4.00 5.15 6.00 7.03 8.02
8.57
X-25961 2.6 11 14 19 47 51 44 54 50
X-25971 77 248 273 295 587 543 391 342 267
1An average of three samples for each time point is reported
[0201] In a separate evaluation of Films X-2596 and X-2597 using Method One,
the C102
gas release was monitored during a period of 10 hrs after initiation to 13 hrs
after initiation.
The concentration of the released C102 concentration from Films X-2597 was
steady while
no released C102 from Films X-2596 was detected.
[0202] Additionally, Film X-2597 routinely provides a peak concentration of
the released
C102 gas at about 1000 ppm under the Method One conditions. The following
table
represents the release profile of the entrained polymer film X-2597.
Time (hrs) 0 1 2 3 4 5 6 7
[C102] (ppm) 0 45 466 796 951 983 870 729
Example 9 ¨ Deg-radant Analysis
[0203] Packages in Example 2 shown in FIG. 7 with entrained polymer film X-
2597 were
analyzed for contents of possible degradants of C102. Headspace samples
underwent a
colorimetric analysis for C102 gas. Residual juice and tomato samples (matrix)
underwent
an ion chromatography for the known C102 degradation products chlorate,
chlorite, and
CA 3043566 2019-06-07
chloride. Initial studies involving spiking the product matrices with C102 vas
showed no
detectable chlorine dioxide in the residual juice and tomato samples, possibly
due to the
active redox environment as a result of the native ascorbic acid. Thus, the
matrix was not
analyzed for chlorine dioxide.
102041 Headspace C102 concentration was measured up to 48 hours (results after
36 hrs not
shown in Table 12 below). After about 16 hours, no headspace C102 was
detected.
Table I 2. Headspace C102 concentration (data from 36 hrs to 48 hrs omitted).
Sample ID Time point Headspace
(Tray ¨ Rep) hr Chlorine dioxide
(ppm or Oil)
1-1 0 <1.66
1-2 0 <1_66
2-1 1 2.65
2-2 1 <1.66
3-1 2 <1_66
3-2 2 <1.66 __
4-1 3 2.48
4-2 3 3.15
5-1 4 6_79
5-2 4 <1_66
6-1 6 2.93
6-2 6 2_20
7-1 8 <1_66
7-2 8 <1_66
8-1 10 5.47
8-2 10 5.13
9-1 12 1_99
9-2 12 2_98
10-1 14 9.11
10-2 14 <1.66
11-1 16 <1_66
11-2 16 629
12-1 18 <1.66
12-2 18 <1.62
13-1 20 <1_69
13-1 20 <1.66
14-1 22 <1.69
14-2 22 <1_69
15-1 24 <1.66
15-2 24 <1.66
16-1 28 <1_66
16-2 28 <1_66
17-1 32 <1.66
17-2 32 <1_66
18-1 36 <1_66
18-2 36 <1.66
56
CA 3043566 2019-06-07
"<" indicates no detected chlorine dioxide above the instruments detection
limit given.
102051 Results of the tomato slices are shown in Table 13 below.
57
CA 3043566 2019-06-07
...
Table 13. Content analysis of tomato slices.
Sample ID Time point Chlorate Chlorite Chloride
(Tray - Rep) , hr mg/kg mg/kg mg/kg
1-1 0 <0.782 <0.391 39.1
1-7 0 <0.785 , <0_393 39_0
2-1 1 <0.795 <0_397 34.7
2-7 1 <0.773 <0_387 32_7
3-1 2 <0.775 <0_387 36.3
3-7 2 <0.766 <0_383 37.4
4-1 3 <0.797 <0.398 31.8
4-2. 3 <0.793 <0.397 43_9
5-1 4 <0.791 <0.396 34.4
5-7. 4 <0_797 , <0.398 34_7
6-1 6 <0_784 , <0_392 42.1
6-7 6 <0.793 <0_397 31_6
7-1 8 <0_789 <0.394 40_9
7-2 8 <0.793 <0_396 31_3
8-1 10 <0.797 <0_399 38.9
8-2 10 <0.800 <0.400 42_3
9-1 12 <0.799 <0_399 33_4
9-7 12 <0.797 <0.399 35.2
10-1 14 <0_792 <0.396 , 41.3
10-2 14 <0.795 <0.398 , 40.7
11-1 16 <0.795 <0_397 38_7
11-2 16 <0.785 <0.393 36_1
12-1 18 <0.791 <0_395 43.4
12-2 18 <0.792 <0.396 36_4
13-1 20 <0_794 <0_397 45_6
13-7 20. <0.798 <0_399 41.4
14-1 27 <0.803 <0.401 53.0
14-2 72 <0.801 <0.400 41.2
15-1 74 <0.801 <0.400 47.3
L 15-2 24 <0.796 <0.398 50.5
"<" indicates no detected chlorine dioxide above the instruments detection
limits given.
102061 Results of degradant contents of the tomato juice are shown in Table 14
below.
58
CA 3043566 2019-06-07
Table 14. Content analysis of tomato juice.
Sample ID Time point C' hlo rate Chlorite Chloride
(Tray - Rep) hr inglkc,F , im.,,fkg mg/kg
1-1 0 <1..99 <0.997 128
1-2 0 <2_00 <1.00 135
2-1 1 <1.99 <0.997 135
7-2 1 <2.00 <0.999 131
3-1 2 <2.00 <1.00 125
3-2 2 <2_00 <1.00 136
4-1 3 <7_00 <0.998 112
4-2 3 <1.99 <0.993 130
5-1 4 <2_00 <0.998 171
5-2 4 <1.99 <0.997 145
6-1 6 <2_00 <1.00 129
6-2 6 <1_94 <0.969 126
'
7-1 8 <1.99 <0.994 125
7-7 8 <1_98 <0.992 117
8-1 10 <1_99 <0.997 130
8-7 10 <1_96 <0.980 133
9-1 17 <1_99 <0.994 177
9-2 12 <1_99 <0.997 120
10-1 14 <1.99 <0.996 114
10-2 14 <1.99 <0.993 110
11-1 16 <2.00 <0.999 142
11-2 16 <2_01 <1.00 132
12-1 18 <7.00 <0.999 12.9
17-2 ____________ 18 <1.99 <0.994 177
13-1 20 <1_99 <0.996 120
13-2 10 <1_98 <0.989 128
14-1 12 <1.99 <0.997 149
14-2 22 <1.99 <0.996 120
15-1 24 <2.00 <0.999 129
15-7 74 <1.99 <0.997 111
"<" indicates no detected chlorine dioxide above the instruments detection
limits given.
102071 Additionally, tomato slice extracts and juice sample were spiked with
chlorate,
chlorite, and chloride to determine the matrix effects. The chlorite
recoveries were low,
ranging from 0-69%, likely due to the redox power of the matrix. On the other
hand, chloride
recoveries were high, ranging from 137% to 151%, indicating conversion from
chlorite to
chloride. Chlorate recoveries were from 100% to 110%, indicating its stability
in the matrix.
The results suggest that the matrix provided by the tomatoes promotes
conversion of chlorite
to chloride, at least at the spike concentrations.
[02081 While the invention has been described in detail and with reference to
specific
examples thereof, it will be apparent to one skilled in the art that various
changes and
59
CA 3043566 201 9-0 6-07
modifications can be made therein without departing from the spirit and scope
thereof.
CA 3043566 2019-06-07
