Note: Descriptions are shown in the official language in which they were submitted.
CA 02716051 2010-09-27
TITLE
ANTIMICROBIAL COMPOSITIONS FOR MEAT PROCESSING
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims the benefit of United States Provisional
Application
No. 61/250,067, filed October 9, 2009, the disclosure of which is incorporated
herein
by reference.
BACKGROUND OF THE INVENTION
[0002] This invention relates in general to antimicrobial compositions, and in
particular to antimicrobial compositions for meat processing.
[0003] During meat processing, the meat may encounter microbes which can make
it unsuitable for consumption. The microbes may come from the meat itself, the
contact surfaces during processing, and/or the surrounding environment. The
microbes can range from pathogenic microbes to spoilage organisms that can
affect
the taste, color, and/or smell of the meat.
[0004] Meat processors use a variety of methods during processing to reduce
microbes on meats. These methods include cleaning and sanitizing the
processing
plant environment, applying an antimicrobial composition to the meat,
irradiating the
meat, applying heat, and others.
[0005] Applying an antimicrobial composition to the, meat is a preferred way
of
reducing microbes. However, it is difficult to fornnulate a composition that
is
effective at reducing microbes using ingredients that are acceptable for
direct contact
with meat according to government regulations. Further, it is difficult to
formulate-a
composition that can be applied directly to meat without adversely affecting
its color,
taste or smell.
[0006] A variety of antimicrobial compositions are known for use during the
processing of meats. However, there is still a need for improved antimicrobial
compositions for meat processing.
1
CA 02716051 2010-09-27
SUMMARY OF THE INVENTION
[0007] A 'method of reducing microbes comprises applying to meat during a meat
processing operation an antimicrobial composition. The composition includes an
acid
blend that is a blend of (a) an organic acid selected from the group
consisting of lactic
acid, acetic acid, and mixtures thereof, and (b) a second material selected
from the
group consisting of alkali metal salts of an inorganic acids, mineral acids,
and
mixtures thereof.
= [0008] In a particular method, the antimicrobial composition includes an
organic
acid and an alkali metal salt of an inorganic acid, and the amount of the
alkali metal
salt is sufficient to keep substantially all the organic acid in the
undissociated form of
the acid.
[0009] An antimicrobial composition for applying to meat during a meat
processing operation comprising an acid blend in an aqueous medium. The acid:
blend
includes a blend of (a) an organic acid selected from the group consisting of
lactic
acid, acetic acid, and mixtures thereof, and (b) a second material selected
from the
group consisting of alkali metal salts of an inorganic acids, mineral acids,
and
mixtures thereof.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0010] The present invention relates to antimicrobial compositions for meat
processing. The antimicrobial compositions include a particular acid blend
that is
effective for reducing microbes, and that comprises food grade acids which are
safe
for human consumption. The acid blend is a blend of (a) an organic acid
selected
from the group consisting of lactic acid, acetic acid, and mixtures thereof,
and (b) a
second material selected from the group consisting of alkali metal salts of an
inorganic
acids, mineral acids, and mixtures thereof.
[0011] The organic acids for use in the compositions are carboxylic acids.
Lactic
acid (2-hydroxypropanoic acid) has the chemical formula of CH3CHOH000H, and
acetic acid (ethanoic acid) has the chemical formula of CH3COOH.
2
CA 02716051 2010-09-27
n n
[0012] The alkali metal salts of inorganic acids for use in the compositions
convert
to acids when hydrated with sufficient water. Some examples of alkali metals
include
sodium, potassium and lithium, and some examples of inorganic acids include
sulfate,
phosphate and nitrate. In certain embodiments, the metal salts are alkali
metal
bisulfates which include, for example, sodium bisulfate (i.e., sodium acid
sulfate or
sodium hydrogen sulfate), potassium bisulfate (i.e., potassium acid sulfate or
potassium hydrogen sulfate), or mixtures thereof.
[0013] Food grade sodium acid sulfate is manufactured and sold as pHaseT_M by
Jones-Hamilton Co. in Walbridge Ohio. It has been certified as GRAS (Generally
Recognized As Safe), and it meets Food Chemicals Codex, 5th Edition
Specifications.
The sodium acid sulfate is in dry granular crystalline form in particle sizes
that can be
readily and uniformly dispersed and solubilized in aqueous media. In certain
embodiments, the particles having a generally spherical shape with an
average..:
diameter from about 0.03 mm to about 1 mm, typically about 0.75 mm. Also, in.
certain embodiments, the product includes sodium bisulfate in an amount from
about
91.5% to about 97.5% by weight (typically about 93%), and sodium sulfate in an
amount from about 2.5% to about 8.5% by weight (typically about 7%).
[0014] The Jones-Hamilton food grade sodium acid sulfate is low in impurities.
In
certain embodiments, the product contains less than about 0.003% heavy metals
as Pb,
less than about 0.05% water-insoluble substances, and less than about 0.003%
selenium by weight. Also, in certain embodiments, the product has a moisture
content
of less than about 0.8% (measured by loss on drying).
[0015] The mineral acid for use in the antimicrobial compositions includes
inorganic acids such as food grade sulfuric acid, hydrochloric acid,
phosphoric acid,
and mixtures thereof. In certain embodiments, the mineral acid is sulfuric
acid.
[0016] The antimicrobial compositions can include the acid blend alone or in
combination with other ingredients. The antimicrobial composition may have a
range
of physical forms: For example, the composition may be in the form of a
liquid, a
thickened liquid, a gel, or a foam. When in the form of a liquid, the
antimicrobial
composition includes the acid blend dissolved or suspended in a liquid
carrier. In
3
CA 02716051 2010-09-27
0
certain embodiments, the carrier is an aqueous medium that includes water and
sometimes other materials. In other embodiments, the carrier can include an
organic
solvent alone or in a mixture with water.
[0017] The carrier can be included in any suitable amount in the antimicrobial
composition. Generally, the carrier makes up a large portion of the
composition and
may be the balance of the composition apart from the acid blend, adjuvants,
and the
like. In certain embodiments, the antimicrobial composition includes about 80
wt% to
about 99.5 wt% carrier.
[0018] The acid blend can be included in the antimicrobial composition in any
suitable amount. The types and amounts of the materials in the acid blend are
sufficient to cause a significant bacterial reduction. In certain embodiments,
in which
the acid blend is included in an aqueous medium, the acid blend is sufficient
to lower
the pH of the medium to within a range of from about. 0.5 to about 2.5, and
more..
particularly from about 0.7 to about 1.5. Also, in certain embodiments in
which the
antimicrobial composition includes an organic acid and an alkali metal salt of
an
inorganic acid in an aqueous medium or other liquid carrier, the composition
may
include from about 0.2% to about 5% organic acid and from about 0.2% to about
5%
alkali metal salt, more particularly from about 0.5% to about 2.5% organic
acid and
about 0.5% to about 2.5% alkali metal salt, and more particularly from about
0.5% to
about 1% organic acid and about 0.5% to about 1% alkali metal salt.
[0019] Further, in certain embodiments in which the antimicrobial composition
includes an organic acid and an alkali metal salt of an inorganic acid, the
amount of
the alkali metal salt is sufficient to keep substantially all the organic acid
in the
undissociated form of the acid. For example, when the composition includes
lactic
acid and sodium acid sulfate, the amount of the sodium acid sulfate is
sufficient to
keep the lactic acid in the, lactic acid form rather than the lactate form.
While not
intending to be limited by theory, it is believed that the undissociated form
of the acid
is more efficacious for microbial reduction than the dissociated form.
[0020] In certain embodiments, for example when the antimicrobial composition
is
an aqueous medium used for scalding, washing, rinsing or chilling carcasses as
4
CA 02716051 2010-09-27
C)
described below, during use the composition will also include organic
materials from
the carcasses, such as fat, oil, proteins, lipids, carbohydrates and small
solid particles,
which are dissolved and/or suspended in the aqueous medium. The load of the
organic materials can vary depending on the particular carcass processing
operation.
In certain embodiments, the antimicrobial composition during use contains from
about
0.1 wt% to about 5 wt% organic materials.
[00211 The antimicrobial compositions can also include any number of adjuvants
that are useful in the compositions, and that do not substantially inhibit the
antimicrobial efficacy of the acid blend. Such adjuvants can include, for
example,
food grade surfactants, defoaming agents, thickeners and/or aesthetic
enhancing
agents (e.g., flavoring aids, colorants and/or odorants).
[0022] In certain embodiments, the antimicrobial compositions are formed using
materials that are all GRAS or food additives. Also, the compositions may be,
formulated as a ready-to-use composition or a concentrate.
[0023] The antimicrobial composition can be prepared by any suitable
method(s).
The composition may be prepared by combining the above-described components
using processes and procedures well known to those of ordinary skill in the
art. For
example, the acid blend and any other materials can. dissolved or suspended in
an
aqueous medium with suitable mixing.
[0024] The antimicrobial compositions are used for reducing microbes during
meat
processing. The term "microbe" is synonymous with "microorganism," and refers
to
any noncellular or unicellular (including colonial) organism, including all
prokaryotes. Microbes include bacteria (including cyanobacteria), lichens,
fungi,
protozoa, virinos, viroids, viruses, phages, and some algae. In certain
embodiments,
the microbes are bacteria associated with meat, such as Escherichia coli,
Salmonella,
Campylobacter, Listeria, Pseudomonas, Acinetobacter, Moraxella, Alcaligenes,
Flavobacterium, Erwinia, yeast, mold, or the like.
[0025] The term "meat" refers to a portion of an animal that has been cut or
harvested for consumption. It includes all forms of animal flesh, including
the
carcass, muscle, fat, organs, skin, bones and other components that form the
animal.
CA 02716051 2010-09-27
l~
i
The term "carcass" refers to a sacrificed animal prepared or being prepared
for
harvesting or recovering meat, meat products, meat byproducts, or the like.
The
carcass can be skinned, headless, or the like. Animal flesh includes the flesh
of
mammals, birds, fishes, reptiles, amphibians, crustaceans, and other edible
species. In
certain embodiments, the meat is a carcass of beef, pork or poultry.
[0026] The antimicrobial compositions are useful for applying to meat during
meat
processing operations. The compositions may be used during any stage(s) of the
process in which they are effective for reducing microbes on the meat.
[0027] For example, during the processing of meats such as beef and pork, the
carcasses are typically subjected to a carcass wash procedure to remove
contamination. This can be done by any suitable method; for example, by
spraying or
immersing the carcasses using a wash water. Many commercial meat processors
use
wash cabinets for the carcass wash procedure. The wash cabinet is an
enclosure, with
nozzles for spraying the wash water onto the carcass. The wash cabinet allows
adjustment of the spray pattern, the pressure of the water and the volume of
water
applied. The time the carcass is in the cabinet can also be adjusted. The
antimicrobial
compositions can be used in the carcass wash water.
[0028] The beef or pork carcasses are also typically subjected to a chilling
operation near the end of the process to prevent the growth of microbes and to
reduce
meat deterioration while the meat awaits distribution. This can be done by any
suitable method, for example, by spraying or immersing the carcasses using
cold
water. Many commercial meat processors use a spray chill system for the
chilling
operation. The spray chill system includes nozzles for spraying the chill
water onto
the carcass, and allows for adjustment in the spray pattern, the pressure of
the water,
the volume of water applied, the temperature of the water, and the duration of
the
spray. The antimicrobial compositions can be used in the carcass chill water.
[0029] After chilling, the primal (better quality) cuts of meat are removed
from the
carcass. What is left on the skeleton after removal of the primal cuts is
known as the
"trim" or "trimmings," because these materials are often trimmed off the
skeleton and
used to make ground beef or ground pork. The trimmings can be treated with the
6
CA 02716051 2010-09-27 \1
antimicrobial composition either before or after their removal from the
skeleton, for
example, by spraying or immersing the trimmings using an aqueous medium
including
the antimicrobial composition.
[0030] As another example, during the processing of poultry the antimicrobial
compositions can be used in the water applied during any of the stages of the
processing operation. Poultry processing typically begins with sacrificing the
bird
followed by neck cutting and bleeding. A first washing step, known as
scalding,
.typically follows bleeding and loosens attachment of feathers of the bird.
Submersion
scalding typically includes immersing the carcass into a scalding hot bath of
water.
After scalding, the carcass is typically defeathered before the next washing
process.
This, post-scalding washing process is generally a rinsing process known as a
dress
rinsing. The rinsing typically includes spraying the carcass with water, or
alternatively flood rinsing or submersing the carcass.
[0031] Typically, the carcass is dismembered and eviscerated and then
subjected to
another washing process. The washing process is known as inside-outside bird
washing, and typically includes rinsing the interior and exterior surfaces of
the carcass
with streams or floods of water. After washing, the interior and exterior of
the bird
can be subjected to further decontamination by spray rinsing. After spray
rinsing, the
bird can be made ready for packaging or further processing by chilling.
Submersion
chilling includes submersing the carcass in cold water or slush, and both
washes and
cools the bird to retain quality of the meat.
[0032] The antimicrobial composition can remain on the meat after the meat
processing operation, or the composition can be removed from the meat.
[0033] In addition to being applied to meat during meat processing operations,
the
antimicrobial compositions can also be useful for application to meat
processing -
surfaces. The phrase "meat processing surface" refers to a surface of a tool,
a
machine, equipment, a structure, a building, or the like that is employed as
part of a
meat processing operation. Examples of meat processing surfaces include
surfaces of
meat processing or preparation equipment, of meat processing wares, and of
floors,
walls, or fixtures of structures in which meat processing occurs.
7
CA 02716051 2010-09-27
[0034] The antimicrobial compositions can have any suitable degree of
effectiveness for reducing bacteria and other microbes. In certain
embodiments, the
antimicrobial composition is effective to reduce at least one of E. coli
bacteria or
Salmonella bacteria by at least 1 log-unit after 5 minutes exposure time as
measured
by AOAC Method 960.09. In some particular embodiments, the composition reduces
bacteria by at least 2 log-units after 5 minutes exposure time, and/or it
reduces
bacteria by at least 1 log-unit after 1 minute exposure time. For example, the
bacteria
which are reduced may be E. coli 0157:H7 ATCC #43894 and/or Salmonella
serotype
enteritidis (ATCC 13076) or others.
[0035] Also, in certain embodiments, the acid blend has a synergistic effect
in
reducing microbes compared with lactic acid alone. For example, the
antimicrobial
composition including the acid blend, when compared with a control
antimicrobial
composition including an amount of lactic acid equal to.the total amount of
the:acid
blend, causes at least twice the bacterial reduction after 1 minute and 5
minutes
exposure time. In other words, when the same amount of materials are used in
an acid
blend compared with lactic acid alone, the antimicrobial composition is at
least twice
as effective in reducing microbes.
[0036] In certain other embodiments, the antimicrobial composition including
the
acid blend, when compared with a control antimicrobial composition including
an
amount of lactic acid which is 33 wt% greater than the total amount of the
acid blend,
causes at least twice the bacterial reduction after 1 minute and 5 minutes
exposure
time. In other words, even compared with a composition containing a greater
amount
of acid, the acid blend is still at least twice as effective in reducing
microbes.
8
--- - ------- --
CA 02716051 2010-09-27
l
EXAMPLE I
[0037] Objective: To evaluate the efficacy of blends of sodium acid sulfate
(SAS)
and lactic acid (LA), compared with lactic acid alone, in reducing bacteria on
growth
medium (TSA).
[0038] Methods:
[0039] The research used sodium acid sulfate provided by Jones-Hamilton Co.
and
lactic acid from a commercial supplier. Test acid solutions of lactic acid,
and of lactic
acid plus SAS, were prepared in sterile deionized (DI) water and in sterile
deionized
water with organic material (0.3% horse blood serum, HBS). Assay control
solutions
of sterile Butterfield's phosphate buffer (BPB) were also prepared with and
without
HBS. About 200 ml of each solution was prepared, and the pH of the solution
was
measured prior to initiating the inoculated portion of the study. The test
acid solutions
and assay control solutions are listed below:
1) 2% lactic acid in DI water, pH 2.34
2) 2% lactic acid in DI water w\ 0.3% HBS, pH 2.39
3) 1% lactic acid plus 0.5% SAS in DI water, pH 2.05
4) 1% lactic acid plus 0.5% SAS in DI water w\ 0.3% HBS, pH 2.11
5) 1% lactic acid plus 1.0% SAS in DI water, pH 2.01
6) 1% lactic acid plus 1.0% SAS inDI water w\ 0.3% HBS, pH 1.99
7) Assay control 1: BPB, pH 6.82
8) Assay control 2: BPB w\ 0.3% HBS, pH 6.75
[0040] The following strains of Salmonella were used in this study: Salmonella
serotype enteritidis (ATCC 13076), Salmonella serotype typhimurium (ATCC
14028),
Salmonella serotype montevideo (ATCC 8387), Salmonella serotype newport (ATCC
6962), and Salmonella serotype choleraesuis (ATCC 13312). The following
strains of
E. coli 0157:H7 were used in this study: ATCC #43894, ATCC #43895, and ATCC
#700599. These bacterial strains are derived from clinical or animal sources
and are
commonly used in process validation, intervention validation, and preservative
efficacy studies with meat and poultry products.
[0041] Each bacterial strain was grown separately via at least two serial
transfers at
35 C for 24 hr in tryptic soy broth (TSB). Bacterial cells for each culture
were
harvested by centrifugation at 10,000 x g for 10 min and washed twice with
BPB,
9
CA 02716051 2010-09-27 /
0
pH 7.2. Each strain was then resuspended, equally combined, and concentrated
in
BPB to obtain a cell suspension of about 5 x 109 CFU/ml. All inoculum
suspensions
were enumerated on appropriate media.
[0042] A modification of AOAC Method 960.09 (Germicidal and Detergent
Sanitizing Action of Disinfectants) was used to test the antimicrobial
efficacy of the
test solutions:
1) For each of the acid test solutions and assay control solutions, eight
sterile.
screw cap test tubes containing 9.9 ml of the solution were prepared. The
tubes
with solutions were equilibrated to room temperature (21-24 C) before
initiating the efficacy tests.
2) For each inoculum, four test tubes of each solution prepared as above were
inoculated by adding 0.1 ml of the designated inoculum suspension (at 1 x 109
CFU/ml). This yielded an inoculum level of about 107 CFU/ml in each tube.
The tubes were vortexed immediately after inoculation and prior to each
sample aliquot collection.
3) For each inoculum/solution combination, two tubes were sampled 1 min after
inoculation and two more tubes 5 min after inoculation.
4) Tubes were sampled by aseptically transferring a 1.0 ml aliquot to a
dilution
blank/tube containing 9.0 ml of D-E neutralizing broth to yield an initial
dilution of 1:10 (10-1).
[0043] Sample aliquots from the initial (10-1) D-E neutralizing tubes were
serially
diluted in BPB and enumerated via surface plating on pre-poured plates of
tlyptic soy
agar. The plates were then incubated for 24 h at 35 C.
[0044] Bacterial counts were expressed as colony forming units (CFU) per ml of
sample solution and converted to log10 transforms. Microbial counts were
transformed to log10 CFU/ml. The log10 and percentage reductions (versus the
respective control sample) were calculated for each inoculum/solution/time.
[0045] Results:
[0046] As background, bacterial log-unit (log10) reduction is synonymous with
lethality, inactivation, and/or bactericidal activity. Bacterial reductions of
less than 1
CA 02716051 2010-09-27
n
log-unit are considered to be insignificant. Log-unit reductions are
equivalent to
percentage reductions as follows: I log-unit = 90% reduction, 2 log-units =
99%
reduction, 3 log-units = 99.9% reduction, 4 log-units = 99.99% reduction, and
5 log-
units = 99.999% reduction.
[0047] The results for Salmonella inactivation presented as log-unit
reductions
after 1 and 5 min exposure times in the acid solutions are shown below in
Table 1.
Salmonella reductions after a 5 min exposure time were greater than
corresponding
reductions after a 1 min exposure time for all acid solutions. The acid
solutions with a
combination of SAS and lactic acid (LA) were more effective in reducing the
Salmonella than corresponding "2% LA only" solutions at each. exposure time.
Salmonella reductions were generally not affected by the presence of organic
matter
(0.3% HBS) in the acid solutions. The Salmonella counts were significantly
reduced
(i.e., >1 log-unit) in the clean and dirty "SAS plus LA" solutions after 1 min
whereas
reductions in the clean or dirty "2% LA only" solutions were not significant
after 1
min. The Salmonella counts were significantly reduced (i.e., >1 log-unit) in
all acid
solutions after a 5 min exposure time. Salmonella reductions after 5 min in
the clean
"2% LA only" solution, the clean "1%LA + 0.5% SAS" solution, and the clean "1%
LA + 1% SAS" solution were 1.22, 2.67, and 4.50 loglo units, respectively
(equivalent
to 93.974%, 99.786%, and 99.997%, respectively).
[0048] The results for E. coli 0 157:H7 inactivation presented as log-unit
reductions after 1 and 5 min exposure times in the acid solutions are shown in
Table 2.
The acid solutions were not as effective against E. coli 0 1 57:H7 as they
were against
Salmonella. None. of the acid solutions was effective in reducing the E. coli
0157:H7
after a 1 min exposure time. Additionally, neither the "2% LA only" nor the
"1% LA
+ 0.5% SAS" solutions were (significantly) effective against E. coli 0157:H7
after a.5
min exposure. However, the "1% LA + 1 % SAS" solutions (with or without the
presence of organic matter) were effective in reducing E. coli 0157:H7 counts
(i.e.,
>1 log-unit) after a 5 min exposure. E. coli 0157:H7 reductions after 5 min in
the
clean and dirty "1 % LA + 1% SAS" solutions were 1.03 and 1.19 log10 units,
respectively (equivalent to 90.67% and 93.54%, respectively).
11
CA 02716051 2010-09-27
Table 1. Antimicrobial Effect of Acid Combinations Against Salmonella
Exposure Time
1 minute 5 minutes
Solutions CFU/ml Log10 CFU/ml Log10
CFU/ml CFU/ml
Control rep. 1 17,000,000 7.23 21,000,000 7.32
(buffered water, BPB) rep. 2 8,900,000 6.95 22,000,000 7.34
Mean 7.09 7.33
2% LA rep. 1 4,700,000 6.67 1,400,000 6.15
(DI water) rep. 2 4,300,000 6.63 1,200,000 6.08
Mean 6.65 6.11
Log10 reduction 0.44 1.22
1% LA & 0.5% SAS rep. 1 490,000 5.69 34,000 4.53
(DI water) rep. 2 3,000,000 6.48 62,000 4.79
Mean 6.08 4.66
Logl O reduction 1.01 2.67.
1% LA & 1% SAS rep. 1 220,000 5.34 470 2.67
(DI water) rep. 2 950,000 5.98 1,000 3.00
Mean 5.66 2.84
LoglO reduction 1.43 4.50
Control w/ organic rep. 1 11,000,000 7.04 15,000,000 7.18
material rep. 2 23,000,000 7.36 15,000,000 7.18
(0.3% HBS in BPB) Mean 7.20 7.18
2% LA w/ organic rep. 1 4,300,000 6.63 690,000 5.84
material rep. 2 4,900,000 6.69 820,000 5.91
(0.3%o HBS in DI Mean 6.66 5.88
water) Log10 reduction 0.54 1.30
1% LA & 0.5% SAS rep. 1 580,000 5.76 26,000 4.41
w/ organic material rep. 2 1,600,000 6.20 .40,000 4.60
(0.3% HBS in DI Mean 5.98 4.51
water) Log10 reduction 1.22 2.67
1% LA & 1% SAS rep. 1 300,000 5.48 24,000 . 4.38
w/ organic material rep. 2 680,000 5.83 9,600 3.98
(0.3% HBS in DI Mean 5.65 4.18
water) LoglO reduction 1.55 '2.99
Notes: 1) Pathogen counts expressed as CFU per ml of inoculated solution.
2) Log reduction .= (log-unit count of respective "control" solution) - (log-
unit count
of respective antimicrobial solution).
12
CA 02716051 2010-09-27
Table 2. Antimicrobial Effect of Acid Combinations Against E. Coli
Expos re Time
1 minute 5 minutes
Solutions CFU/ml Log10 CFU/ml Log10
CFU/ml CFU/ml
Control rep. 1 24,000,000 7.38 16,000,000 7.20
(buffered water, BPB) rep. 2 20,000,000 7.30 16,000,000 7.20
Mean 7.34 7.20
2% LA rep. 1 27,000,000 7.43 22,000,000 7.34
(DI water) rep. 2 23,000,000 7.36 22,000,000 7.34
Mean 7.40 7.34
Logl0 reduction -0.06 -0.14
1% LA & 0.5% SAS rep. 1 17,000,000 7.23 12,000;000 7.08
(DI water) rep. 2 25,000,000 7.40 9,900,000 7.00
Mean 7.31 7.04
Lo i0 reduction 0.03 0.17
1% LA & 1% SAS rep. 1 11,000,000 7.04 1,300,000 6.11
(DI water) rep. 2 .11,000,000 7.04 1,700,000 6.23
Mean 7.04 6.17
LoglO reduction 0.30 1.03
Control w/ organic rep. 1 16,000,000 7.20 23,000,000 7.36
material rep. 2 16,000,000 7.20 39,000,000 7.59
(0.3% HBS in BPB) Mean 7.20 7.48
2% LA w1 organic rep. 1 18,000,000 7.26 20,000,000 7.30
material rep. 2 22,000,000 7.34 21,000,000 7.32
(0.3% HBS in DI Mean 7.30 7.31
water) Log10 reduction -0.094 0.16
1% LA & 0.5% SAS rep. 1 22,000,000 7.34 4,900,000 6.69
w/ organic material rep. 2 21,000,000 7.32 11,000,000 7.04
(0.3%HBS in DI Mean 7.33 6.87
water) Lo lO reduction -0.13 0.61
1% LA & 1% SAS rep. 1 14,000,000 7.15 1,500,000 6.18
w/ organic material rep. 2 19,000,000 7.28 2,500,000 6.40
(0.3% HBS in DI Mean 7.21 6.29
water) LoglO reduction -0.01 1.19
Notes: 1) Pathogen counts expressed as CFU per ml of inoculated solution.
2) Log reduction = (log-unit count of respective "control" solution) - (log-
unit count
of respective antimicrobial solution).
13
CA 02716051 2010-09-27
O lv2
[0049] In summary, bacterial reductions after a 5 min exposure time were
greater
than corresponding reductions after a 1 min exposure time for all acid
solutions. The
Salmonella counts were significantly reduced (i.e., >_l log-unit) in all acid
solutions
after a 5 min exposure time with the combination LA/SAS acid solutions being
more
effective than the corresponding "2% LA only" solutions. None of the acid
solutions
was effective in reducing the E. coli 0157:H7 after a 1 min exposure time. The
"1 %
LA + I% SAS" solution was the most effective acid solution against both
pathogens
and was the only acid solution effective in reducing E. coli 0 157:H7 by at
least one
log unit (after 5 min).
14
CA 02716051 2010-09-27
_J
EXAMPLE 2
[0050] Objective: To evaluate the efficacy of blends of sodium acid sulfate
(SAS)
and lactic acid (LA), compared with lactic acid alone, in reducing bacteria on
beef
samples.
[0051] Procedure: Beef plates will be cut into 15x40cm sections. The plates
will
be inoculated with an E. coli surrogate cocktail consisting of ATCC BAA-1427,
BAA-1428, BAA-1429, BAA-1430, and BAA-1431. After inoculation, the samples
will be stored at 4 C for 20 minutes to allow bacteria to attach to the meat
samples.
[0052] Beef plate sections will be run through a custom built spray cabinet
(Chad
Company, Olathe, KS) at set specifications where treatment will be applied.
Treatments include 5% total solids (2.5% Lactic Acid/2.5% Sodium Acid Sulfate
(SAS)), 3% total solids (1.5% Lactic Acid/1.5% SAS), 2.5% Lactic Acid, 2.5%
SAS,
5% Lactic Acid, and water. After treatment is applied, samples will be allowed
to drip
dry for 20 minutes at 4 C. After samples have been allowed to drip dry, a 100
cm2
section will be excised and placed in stomacher bag. Beef plate sections and
pork
butts will be vacuum packaged and stored at 4 C.
[0053] Four 100 cmZ sections will be excised from the plates. The first
excision
will be taken at time zero, twenty minutes after treatment is applied. The
second and
third excision will be removed at 24 and 48 hours post-treatment. A final
excision
will be removed at 20 days post-treatment. Excised samples will be placed into
a
filtered stomacher bag with 225 ml of peptone water. Samples will homogenized
for
two minutes and a dilution series will be conducted to dilute the sample to a
10-4
dilution. The diluted samples will be plated on Trypticase Soy Agar and Violet
Red
Bile Agar with MUG, which selects for coliforms including E. coli, and
incubated at
37 C for 48 hours. Bacterial colonies will be counted and total plate counts
will be
calculated.
