Note: Descriptions are shown in the official language in which they were submitted.
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NON TOXIC. NON COl~ROSIVE MICROBICIDAL COMPOSlTION
Back~round of the Invention
Field of the Invention
This invention relates generally to microbicidal compositions and
more particularly to s~niti7ing and microbicidal compositions which may be used to
sanitize surfaces and equipment used to prepare, process or m~nllfactllre food,
ph~ ceutir~l~ or other preparations which require protection from contact with
microbial cont~min~tion during m~nnf~rture.
Sumrnary of the Invention
This present invention provides unique non-toxic, non-corrosive
s~niti7.ing and microbicidal compositions which may be used to sanitize surfaces and
equipment used to prepare, process or m~nllf~cture food, pharmaceuticals or other
preparations which should receive protection from contact with microbial
cont~min~tion during manufacture. More generally these compositions may be used
wherever there is a desire to subst~nti~lly reduce or elimin~te residual microbial
cont~min~tion which may reside on equipment surfaces or in ancillary equipment
such as valves, pipes, filters, etc. Today the safety of such compositions to hllm~nc
and/or ~nim~ that may come into contact with the composition, its use dilutions or
with residuals from the composition which are introduced into the fini.~h~.~ product is
under increasing scrutiny. The environrnental acceptability of such compositions in
terms of non-toxicity to life in both treatm-qnt plants and llltim~te receiving waters is
also an important consideration.
In brief, the non-toxic, non-corrosive microbicidal compositions of the
present invention comprise:
(a) a water soluble, short chain organic acid component having the
formula:
R--COOH
where R is a short chain carbon compound with a carbon chain length
in the range of Cl--C4, said short chain organic acid component
providing an acid pH value in a range of about 1.5 - 4.0 upon dilution
with an excess of water;
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(b) an intermediate chain length fatty acid component having the formula:
R'--COOH
where R' is an aliphatic, straight or branched chain carbon compound
with a carbon chain length in the range of C6--Cl6;
(c) a non-toxic phenolic compound;
(d) an effective amount of a solubilizer which is capable of solubilizing
the intermediate chain length fatty acid component (b) and the
phenolic compound (c) when the microbicidal composition is diluted
with water; and
(e) optional components which may be added to control or enhance foam,
aid in control of water hardness, viscosity and stability, or further
enhance the antimicrobial activity of the composition.
The short chain organic acid of the composition may be chosen from
.among the naturally occurring food grade acids generally described as water soluble
such as lactic, acetic, citric, malic, succinic, natural amino acids, and the like. In
general such acids have four or fewer carbon atoms in their carbon backbone and
they may also contain other substituent groups such as --OH, --NH2, etc., which
commonly may be found in such acids. Many such acids have a long history of use
in human food and are regarded as either food acidulants or as vital food ingredients
(amino acids).
The intermP~ te chain length fatty acid component of the
composition, with a carbon chain length in the range C6--C,6, may include functional
groups such as --OH, --NH2, etc., or may alternatively contain carbon atoms
involved in bonds other than sigma bonds. Examples of such acids are caprylic,
pelargonic, undecylenic, sorbic, etc., the acids being limited to those which are
understood to have a long history of use in food or food related products are non-
toxic and recognized as compounds having no adverse effects on hllm~n.s.
The phenolic compound of the composition is chosen from that group
of compounds which heretofore have been classified as antioxidants and whose
advantageous anti-microbial properties have previously been ignored. From this
group the preferred subset is the group of anti-oxidants having a long history of use
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in food products and which belong in the group of compounds "generally recognized
as safe" (GRAS). Microbicidal properties of phenolic compounds have been
described in Chapter 9 of Disinfection, Sterilization, and Preservation, 3d Ed.,Edited by Carl A. Lawrence and Seymour S. Block, Lea & Febiger, Philadelphia,
PA, (1983). The use of such compounds in an antimicrobial composition to enhancethe antimicrobial activity of said composition is herein described for the first time.
The solubilizer of the composition is a hydrotrope or a surface active
agent chosen from the classes of anionic, cationic, amphoteric or non-ionic surface
active agents. The preferred surface active agents are those with a history of use in
food and ph~rm~eutical applications whose toxicity is well understood.
As already indicated, a variety of optional components may be added
to control or enhance foam, or to aid in controlling water hardness, viscosity and
stability, or further enhance the antimicrobial activity of the composition.
Description of the Preferred Embodiments
While the invention will be described in terms of its p~ d
embodiments, it should be understood that this is not intended to limit the invention
to those embodiments. On the contrary, it is intended to cover all alternatives,modifications and equivalents which fall within the spirit and scope of the invention
as detailed in the appended claims.
The composition is acidic in nature and the major portion of the
acidity is provided by the non-toxic short chain water soluble organic acids which
have a history of use in food or food related products, are non-toxic and are
recognized as compounds which have no adverse effects on hnm~n.~. In addition,
the majority of these acids in their dilute state are non-corrosive to equipmentsurfaces at the inten(led use dilutions which are described further hereinbelow for
this invention. They are known to be less corrosive than the strong mineral acids
which have previously been used in microbicidal solutions. The overall structure of
these acids may be represented as:
R--COOH
where R is a short chain carbon compound possibly carrying other substituent groups
of general carbon chain length 1-4. Examples of such acids are formic, acetic,
propionic, butyric, etc. However, the inclusion of substituent groups in the
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definition leads to the inclusion of substituted and branched chain acids such as for
example:
Lactic Acid R = CH3CHOH--
Glycolic Acid R = CH2OH--
Alanine R = NH2CH2CH2--
The definition is not confined to the presence of one substituent group since the R
group in the original definition may carry multiple substituent groups and even
additional acidic groups such as:
Cysteine R = HS--CH2CNH2H2--
Malonic, Succinic, Glutaric Acids R = HOOC--(CH2)n--
Malonic (n=1), Succinic (n=2), Glutaric (n=3) Acids
The intervening group may again carry substituents such as, for
example, in malic or citric acid:
Malic Acid R = HOOC--CH2CHOH--
Citric Acid R = HOOC--CH2C(OH)(COOH)CH2--
The second major constituent of the invention is the intermediate
chain length organic acid generally described by chain lengths in the range C6 to Cl6
which may or may not carry substituent groups. These substituent groups may or
may not be additional acid (carboxyl) groups. Examples of such acids are the
straight chain fatty acids of general formula,
R --COOH
where R is a straight or branched chain aliphatic group. Examples of such acids are
as follows:
R = CH3~~(CH2)n~~
Caprylic (n=7) or Pelargonic (n=8)
R = CH3--C(CH3)2--CH2 CH(CH3)--
iso-octanoic acid
Additionally, the R group may contain 1 or more double or triple
bonds which leads to acids of the forrn such as:
R = CH2 =CH~~(CH2)n~~
undecylenic acid n=(8)
decylenic acid n=(7)
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The R group may also contain attached substituent groups such as are
shown by octenyl succinic acid or octyl succinic acid:
R = HOOC--CH2--CH(R')--
Rl = CH2 =CH--(CH2)6-- (octenyl succinic acid)
R' = CH3--(CH2)7--(octyl succinic acid)
The R group may also contain double or triple bonds in addition to
other substituent groups such as for example:
Sorbic Acid R = CH3--CH=CH--CH= CH--COOH
2-Amino-4-hexenoic Acid R = CH3--CH=CH--CH2NH2CH = CH--
Although the above definitions may serve to illustrate the definition of
interm~ te chain acid they are not meant to be limiting or exclusive of other
interm~ te chain acids which fall under the general category of acids which are
common in foods and are generally considered to be non-toxic.
The third and most novel component of the compositions according to
the present invention comes from the group of non-toxic phenolic compounds having
.anti-oxidant properties. Examples of such compounds are BHT (Butylated hydroxy
toluene), BHA (Butylated hydroxy anisole), TBHQ (tertiary butyl hydroxy quinone)and natural analogues with similar anti-oxidant properties such as the tocopherols,
cinn~mic acid compounds and compounds generally described as flavins or
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flavinoids. A few such formulae are shown below:
r- - ~c A~id C~CH-COO~
CH3
H3C~J~CI n33 alpha-locol,h~
CH3
la~one
HO ~1
The use of these phenolic compounds to specifically enhance and
increase the efficacy of the s~niti7.ing composition is herein described for the first
time.
The fourth component of the compositions according to the present
invention is a solubilizer. This component may be a surfactant or a hydrotrope
which is able to bring and retain all of the components of the composition into
solution or stable emulsion, not only in the concentrate but also in the diluted use
solutions which are made from the concentrate. The surfactant may be chosen fromamong the wide range of surfactants that are available including anionic, non-ionic,
amphoteric and cationic.
The surfactant may be a sulfosuccinate. As is well known to one
skilled in the art these compounds based on succinic acid are anionic sulfonatedsurfactants whose toxicological and environmental properties are well understood.
Examples of such compounds are dioctyl sodium sulfosuccinate, commercially
available as Solusol~FG from American Cyanamid Co., Linden, NJ, dioctyl,
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dihexyl, di-isobutyl and ditridecyl sulfosuccinates commercially available under the
mark Monawet~ from Mona Industries, Inc., Patterson, NJ; diamyl, di-isobutyl,
dioctyl and dihexyl sodium sulfosuccinates commercially available under the markAerosol~ from American Cyanamid Co, Linden NJ; parrafinic and alkylbenzene
sulfonate, commercially available under the mark Witconate~ from Witco Chemical
Company, Houston, TX.
In addition, diphenylether sulfonate adducts commercially available as
Dowfax~2A1 from Dow Chemical, Midland, MI, may be used as surfactants.
Not all surfactants may be equally desirable for use in the
compositions of the present invention. From among the anionic surfactants
sulfonates in general are preferred over sulfates, as sulfates tend to hydrolyze in acid
solutions which may decrease their efficacy as solubilizing agents in liquid
concentrates. However, sulfates may be used in compositions which are dry
powders, where their stability need only exist over the short period of time during
which the prepared use dilution is used.
In addition, the solubilizer component may comprise a combination of
surfactants, since a combination of said surfactants may be utilized to optimizeuseful properties such as rinsability, solubilization, de~ergeney and other propc;~ies
that may be desirable for the composition to possess.
Optional components may be added to control or enhance foam, or to
aid in controlling water hardness, viscosity and stability. In cases where it may be
desirable, one may also add solvents such as limonene, to enhance the cle~ning
action of the composition and also enhance penetration into biofilms, soils, and the
like. As is well known to those skilled in the art, one may also optionally add
e~r~rsul~tin~ agents which encapsulate one or more of the components and permit
either the formation of an emulsion or the formation of a dry powder. Chelating
agents may be added to enhance biological activity, cleaning performance and
control water hardness. In those cases where it is desirable one may also add
fragrances, dyes and bittering agents to enhance the composition for its intended use.
Additional components which further enhance the antimicrobial activity may also be
added.
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THE COMPOSITION AND EXAMPLES
A general formula for a use dilution of the composition is shown in
Table 1.
TABLE 1
5Interme~ te Chain Length Organic 40-140 ppm
Acid
Phenolic (Anti-Oxidant, flavone) 25-75 ppm
Surfactant/Hydrotropes 20-120 ppm
Water Soluble Organic Acid 400-1000 ppm
l 0 Water balance
The novelty of the composition described in Table I resides in the
unique admixture of components. Each component, intermediate chain length fatty
acid, phenolic, surfactant and water soluble organic acid, is known to have somel5 measure of antimicrobial activity. None, by itself, is capable of meeting the.requirements for a s~niti7ing composition at the use dilutions and conditions set forth
herein. However, taken in combination, they function synergistically at high
dilutions with the desired efficacy.
It is well known in the scientific literature that low pH values
20 geneldted by acidic solutions provide an environment hostile to the growth of
microorg~nl.cmc.
Previous patents, such as U.S. Patent No. 4,404,040 issued Sept. 13,
1983 to Wang, for example have described the use of short chain organic acid
solubilized by anionic surfart~ntc in such an acid environment to form a s~niti7.ing
25 composition. It is known in the art that mineral acids such as phosphoric acid are a
preferred acidifying vehicle. The present composition, however, recognizes that
water soluble organic acids and phenolic compounds may be used to augment the
efficacy of these other components.
The present composition also recognizes that the overall anti-microbial
30 efficacy of the composition is enh~nred by the inclusion of these water soluble
organic acids and phenolics, thereby permitting a lower concentration of the other
components. The inclusion of these water soluble organic acids and phenolics in a
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highly acidic composition for killing microorg~ni.cm.c is therefore a novel aspect of
the present composition.
The advantageous use of such components in a sanitizing composition,
their synergistic interaction with the other components in the relatively acidic5 environment of these s~niti7.ing compositions, their non-corrosive nature, in addition
to other useful properties which enhance the use of acidic sanitizing compositions is
herein described for the first time.
Exemplary concentrates of the composition, based on percent
composition, were prepared and are shown in Table 2.
TABLE 2
EXAMPLE 1 2 3 4 5 6 7
Pelargonic Acid 5 10 10 8 8 8 8
TBHQ 3 3 3 3 3 3
BHA -- -- -- -- 3
Lactic Acid 87 so s2.s 4s ss ss so
Citric Acid -- 10
Solusol FG 5 -- -- -- -- -- --
Monawet MO 70 -- 5 -- -- -- -- 5
Aerosol A-268 -- -- 5 -- -- -- --
Witconate NAS-8 -- -- -- 7 6 7
Dowfax 2A1 3 3.s 2.s
Water 32 2s.s 24 24.5 24.5 34
TOTAL 100 100 100 100 100 100 100
The method used for determinin~ anti-microbial activity was the
Germicidal and Detergent Sanitizers Test accepted by the USDA and the EPA. The
method was taken from Methods of Analysis, Association of Official Analytical
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Chemists~ 11th edition (1970) pp 66-68. The use concentrations or dilutions of the
above formulas were all at 1 fluid ounce to 5 gallons of water.
The results of these tests conducted in hard water as specified in the
test (500 ppm as CaCO3) on compositions 1-7 of Table 2 are shown in Table 3.
TABLE 3
EXAMPLE 1 2 3 4 5 6 7
E. Coli ATCC pass pass pass pass pass pass pass
11299 kill
Staph. Aureus pass pass pass pass pass pass pass
ATCC 6538 kill
In this testing an entry of pass indicated that the in~lic~t~ composition
when tested showed a 99.999% or greater kill within 30 seconds of cont~tin~ the
microorg~ni~m~ being tested.
Previous microbicidal compositions do not contemplate the substantial
advantages to be gained from the synergistic functioning of the subject compositions.
The composition described above include components which are
known to have some measure of ~ntimi~robial activity, although none of these active
ingredients is capable of meeting the requirements for a s~niti7ing composition at the
use dilutions and conditions described herein. However, taken in combination, they
function synergi.ctically at high dilutions with the desired efficacy.
The herein described compositions also have other desirable properties
which include low corrosivity, minim~l environrnental impact, and primarily contain
materials which are often present in foods.
This completes the description of the preferred and alternate
embodiments of the invention. Those skilled in the art may recognize other
equivalents to the specific embodiment described herein which equivalents are
intended to be encompa.csed by the claims attached hereto.
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