Note: Descriptions are shown in the official language in which they were submitted.
~xprE s Mail No . IB594190212US
;r
PROCESS FOR TREATING POULTRY CARCASSES TO INCREASE SHELF-LIFE
TO CONTROL SALMONELLA GROWTH
J
The present invention relates to an improved process for reducing the level of
and retarding
the growth of bacteria, such as salmonella, in poultry processing and on raw
poultry without
causing organoleptic depreciation thereof and, in turn, extending the shelf
life of the poultry.
BACKGROUND OF THE INVENTION
Poultry is processed, after slaughtering, by scalding to assist in
defeathering, defeathering
by machine, washing, eviscerating and chilling prior to packing. These
treatments are
controlled to avoid causing a change in the appearance characteristics of
poultry which
would make it unsalable.
Poultry, after eviscerating, shows high levels of salmonella bacteria on the
surface of the
carcass. A large part of carcass contamination with salmonella can be removed
by water
washing. While salmonella can be easily killed by heat, such as during
cooking, colony
,20 forming units of bacteria can attach and/or reside in the regular and
irregular surfaces of
the skin, multiply and, thereafter, contaminate working surfaces, hands and
utensils. Food
spoilage and illness can result from this carry over of bacteria or cross-
contamination from
the infected carcass to surfaces not heated sufficiently to cause thermal
destruction of the
bacteria.
Extensive research has been conducted by the art to uncover an economical
system for
reducing salmonella contamination of poultry carcasses without causing
organoleptic
depreciation. Poultry feathers carry large amounts of salmonella which can
contaminate the
carcass during scalding and defeathering. Improper evisceration can also be a
source of
contamination. The use of acids such as lactic or acetic acid, at levels
sufficient to effect
bacteriological control, causes organoleptic deterioration of the poultry. At
acid levels low
1
~13~6~~; '. _ ='-~il _'°. ~3594190212L;S
enough to avoid organoleptic deterioration of the poultry, bacteriostatic
effects are reduced.
A treatment system must be economical, easy to use, compatible with food
manufacturing,
and not change the organoleptic properties of the poultry. Any change in the
appearance
of the poultry would make the same unsalable.
It has been reported that the thermal death rate of salmonella can be
increased during
scalding by elevating the pH of the scald water to pH 9.0 ~ 0.2. Agents such
as sodium
hydroxide, potassium hydroxide, sodium carbonate, and trisodium phosphate have
been
reported as effective pH adjusting agents for use in increasing the thermal
death rate of the
bacteria. Trisodium phosphate was reported as least effective in increasing
the death rate.
Sodium hydroxide and potassium hydroxide, while effective bacteriostats, can
effect the
surface of the carcass adversely. Propionic acid and glutaraldehyde, which
were also tried
as treating agents, are reported as possibly having unfavorable effects on
plucking. See, '"The
Effect of pH Adjustment on the Microbiology of Chicken Scald-tank Water With
Particular
Reference to the Death Rate of Salmonella," TJ. Humphrey, et al., Journal of
Applied
Bacteriology, 1981, S 1 pp. 517-527.
TJ. Humphrey, et al. have also reviewed the pH effect of scald water on
salmonella on
chicken skin. See 'The Influence of Scald Water pH on the Death Rates of
Salmonella
typhimurium and Other Bacteria Attached to Chicken Skin," Journal of Applied
BacterioloQV. 1984, 57 (2), pp. 355-359. Scald water adjusted to pH 9 ~ 0.2 as
in the 1981
paper can help to reduce external and internal cross-contamination of
carcasses by
salmonellas.
The results reported in the first article are based on assays of samples of
scald water taken
from the scald tank. The article does not show the effect of the agents on
bacterial colonies
on the surface of the poultry or the organoleptic effect on the poultry meat
or skin.
The second paper teaches that pH adjustment of scald water to pH of 9 ~ 0.2
can be used
to improve the hygiene of chicken carcasses during plucking by lowering the
bacterial carry
2
C,aDrE ~ _~iail ':o. IB594L90212US
over from the scald tank.
These references are limited to the scald tank and use relatively low pH
conditions and low
concentration pH adjusting agents and do not show any long term effect of the
agents on
the surface of the poultry since the scald water solution and any agents
therein are washed
off after defeathering.
Humphrey, et al. recognize that plucking and subsequent evisceration cause
further
contamination. The improvements in scalding hygiene reported in their 1984
paper and in
their earlier work [1981] help to reduce the growth rate of pathogens on
carcass surfaces
during plucking but have no measurable effect on the shelf-life or safety of
chilled carcasses
because of further contamination during evisceration. The organisms
responsible for spoilage
of meat of this type are added during cold storage or during later stages of
processing.
(Humphrey, et al. 1984 at page 359). Humphrey, et al. do not teach reducing
the potential
for salmonellosis by reducing the incidence and population of salmonella
organisms.
Humphrey, et al., 1984, also do not show the organoleptic effect of their
treatment on the
poultry carcasses, much of which is undesirable.
Attempts have been made to pasteurize poultry meat by treating the meat with a
solution
containing agents such as lactic acid, acetic acid, sodium carbonate, sodium
borate, sodium
chloride, potassium hydroxide, chlorine and EDTA. All treatments, except
sodium borate,
sodium chloride and sodium carbonate reduced the visual acceptability of the
meat.
Chlorine failed to destroy bacteria on the surface of the poultry but would be
expected to
control salmonella in water. See, Chemical Pasteurization of Poultry Meat J.S.
Teotia,
Dissertation Abstracts Int'l. B., 1974, 34(a), 4142.
The following references treat various meat products to retain moisture,
texture and
tenderness. U.S. 3,782,975 to Zyss issued January 1, 1974 teaches
polyphosphate curing of
fresh primal cuts of meat with a curing solution at pH 6 to 8, free of sodium,
and containing
about 1.0 to 20% by weight of a water soluble phosphate which can include
orthophosphate.
3
~~~:~rrr > ~iaii .;o. ~3~94190212~S
U.S. 3,775,543 to Zyss issued November 27, 1973 uses 0.2 to 20% by weight of a
phosphate
(which can be orthophosphate) treatment solution based on the ingredient mix
of processed
meat. The phosphate is used as a binding agent. Alkaline pH is found to
decrease shelf life.
Salmonella is killed by cooking not by phosphate.
U.S. 3,493,392 to Swartz issued February 3, 1970 pumps tuna with a phosphate
treating
solution including orthophosphate to improve yield of desired light flesh, to
improve odor
(less fishy) and to render the meat more tender and less dry. Pumping injects
solution deep
into the meat or fish and is not a surface treatment. Swartz uses mono and
dialkali
orthophosphate in Example IV and reports poor weight retention results
compared to
polyphosphates. U.S. 3,620,767 to Swartz issued November 16, 1971 pumps bonito
with a salt
and phosphate including orthophosphate but no example is given. See also
Canadian Patent
847,280 issued July 21, 1970 to Swartz. These references employ polyphosphates
for their
water binding properties.
U.S. 2,770,548 teaches the anticaking properties of trialkali metal
orthophosphates.
Trisodium phosphate has also been found to be effective in inhibiting the
growth of blue
mold in cuts and bruises in fruit by treating the broken surface with the
solution of
trisodium phosphate (U.S. Patent No. 1,744,310).
Kohl, et al., U.S. 3,681,091, issued August 1, 1972, teaches treating foods
including fish fillets
with 10% solution of medium chain length polyphosphates.
Freund, et al., U.S. 2,957,770 teach improving the properties of meat with a
composition
which can include inorganic orthophosphates such as disodium hydrogen
orthophosphate.
Low concentrations of phosphate are employed.
Cheng, U.S. 4,683,139 issued July 28, 1987 teaches a process for prepackaged
fresh red meat
at retail wherein the shelf life of the meat is increased by treatment with an
aqueous
4
~:tn- -S ~f311 ::o . _3594190212L'S
solution of an alkali metal salt or certain phosphate compounds, a reducing
compound such
as ascorbic acid and a sequestering or chelating agent such as citric acid.
The phosphate can
be an orthophosphate, pyrophosphate, tripolyphosphate and hexametaphosphate
and will
vary in the way the buffer solution is applied to the meat giving a pH below
neutral.
Szczesniak, et al., U.S. 4,075,357 issued February 21, 1978, teaches salt
combined with a
secondary salt selected from alkali metal salts of organic acids and trisodium
orthophosphate, polyphosphate, metaphosphate and ultraphosphate. Citrates are
preferred
combined with sodium chloride. These mixtures are used to control water
activity in low
moisture cooked food which have neutral pH.
U.S. 3,705,040 to Bynagte issued December 5, 1972 teaches use of a solution of
water, 2 to
3% acid pyrophosphates and 2 to 15% sodium phosphates including sodium
orthophosphate
to soak shrimp for at least two minutes followed by cooking for three minutes,
cooling and
peeling. The process improves the amount of shrimp meat recovered from the
shell by
reducing the strength of the under skin of the shrimp. Where sodium
orthophosphate is
employed in Example IV it is employed at 2%.
The preceding patents which pump or treat meat or fish with phosphates
generally use
?0 needles to inject or mix into meat formulations a phosphate solution to
bind water and
improve texture of the product. Neutral pH formula are employed for these
purposes. The
patents do not teach the present invention of treating the surface of freshly
slaughtered
poultry with trialkali metal orthophosphate at pH 11.5 or greater to remove,
reduce or
retard bacterial contamination or growth on the poultry.
U.S. 4,592,892 to Ueno, et al. issued June 3, 1986 teaches ethanol used to
sterilize foods and
machines can be enhanced by use of an aqueous solution of an alkali carbonate
which may
also contain a trialkali metal phosphate. Trialkali metal orthophosphate as
well as sodium
carbonate and other phosphates is used to treat a broth to reduce E. coli in
Table 1. This
patent fails to recognize that trisodium phosphate per se can remove, reduce
or retard
5
c:c~r s 'sail ::o. ~3~94190212LS
zm7s~~
bacterial contamination on poultry. Orthophosphate is used only in combination
with
ethanol which is a popular disinfectant for machinery and food in Japan.
Thomson, et al. "Phosphate and Heat Treatments to Control Salmonella and
Reduce
Spoilage and Rancidity on Broiler Carcasses," Po_ ultrv Science. 1979, pp. 139-
143, treats
poultry with 6% kena phosphate which is a polyphosphate blend of 90% sodium
tripolyphosphate and 10% sodium hexametaphosphate. The phosphates did not
significantly
or consistently affect salmonella survival or total bacterial growth.
It is known that the shelf life of chicken carcasses can be increased 1 to 2
days by chilling
the poultry in a solution of 6% sodium tripolyphosphate/0.7% tetrasodium
pyrophosphate
(Kena-available from of Rhone-Poulenc Inc.). See, The Antimicrobial Effect Of
Phosphate
With Particular Reference To Food Products. L.L. Hargreaves, et al., The
British Food
Manufacturing Industries Research Association, Scientific and Technical
Surveys, No. 76,
April 1972, pp. 1-20 at page 12. Many patents and articles suggest the use of
polyphosphates
in preserving meat and fish products.
In addition, it is also stated in the Hargreaves reference at page 7 that G.
Pacheco and
V.M. Dias in an article entitled Bacteriolytic Action of Phosphates Mems
Institute, Oswaldo
Cruz, 52 (2), pp. 405-414, reported on the bacteriolytic action of solutions
of monosodium,
disodium, trisodium and dipotassium orthophosphates on dead and living cells
of Salmonella
typhosa. Escherichia coli and Staphylococcus aureus. Trisodium phosphate
dodecahydrate
is stated to have the greatest lytic action. This reference does not relate to
treating poultry.
British Patent 935,413 teaches treating raw poultry in the chill tank with a
non-cyclic
polyphosphate. It is taught that this method provides increased preservation
of the poultry
flesh by decreasing exudate and thereby decreasing spread of bacteria.
U.S. Patent No. 5,264,229 suggests shelf-life extension for commercially
processed poultry
by using a specialized hydrogen peroxide and a surfactant in the water used
for chilling the
6
CA 02137629 2003-09-25
73863-34
poultry.
Commonly assigned U.S. Patent Nos. 5,069,922,
5,143,260, and 5,283,073 are directed to a poultry carcass
wash process which removes or reduces existing salmonella
contamination as well as retards further contamination or
growth without affecting the organoleptic properties of the
poultry carcasses. While this technology has significantly
advanced the art, improvements can still be made in reducing
the overall aerobic bacterial plate count, and thereby
increasing the shelf-life of the poultry.
SUMMARY OF THE PRESENT INVENTION
According to one of the aspect of the present
invention, there is provided a process for treating poultry
carcasses comprising containing the poultry carcass prior to
chilling with a treatment solution containing about 4% or
greater trialkali metal orthophosphate based on the weight
of the solution with the proviso that the treatment solution
does not contain alcohol, said treatment solution having a
pH of at least 11.5, said treatment being conducted for a
period of time effective to reduce the overall aerobic
bacterial count without causing organoleptic depreciation of
the poultry and thereby increasing the shelf-life thereof.
According to another aspect of the present
invention, there is provided a process for treating poultry
carcasses comprising contacting the surface of poultry prior
to chilling with an aqueous treatment solution consisting
essentially of 4% or greater of trialkali metal
orthophosphate based on the weight of the solution, said
treatment solution having a pH of at least 11.5, said
treatment being conducted for a period of time effective to
7
CA 02137629 2003-09-25
73863-34
reduce the overall aerobic bacterial count without causing
organoleptic depreciation of the poultry and thereby
increasing the self-life thereof.
It has been discovered that during poultry
processing from about 4% or more, preferably 8% or more of
trialkali metal orthophosphate may be added to processing
water before the poultry is chilled to elevate the treating
solution to above pH 11.5 and remove, reduce or retard
bacterial contamination and/or growth on poultry.
We prefer to employ the trialkali orthophosphate
treatment immediately after the scalding treatment either
before or after defeathering or during washing of the
poultry prior to evisceration or preferably during the
inside/outside wash after evisceration. These treatments
are conducted using a warm or hot solution and recycling the
solution with filtering to economically utilize the
phosphate. While our prior work suggests that a reduction
in bacteria can occur by treating the poultry either before
or after chilling the carcass, we have surprisingly
discovered that treating the carcass before chilling
dramatically reduces the overall bacterial plate count and
extends the shelf-life of the poultry.
7a
::~r~ ~ _:ail _;o. ~3~94190212t,'S
The process comprises treating poultry at a temperature below that which would
cause
organoleptic depreciation in the poultry which normally is below 65°C,
preferably below
45°C. Cooled poultry is treated below about 27°C. The treatment
solution comprising
trialkali metal orthophosphates, said orthophosphate being present in an
amount and said
poultry being treated for a time sufficient to remove, reduce, or retard
bacteriological
contamination of the poultry, said orthophosphate agent being present in
amounts
insufficient to cause substantial organoleptic depreciation of the poultry.
Such treatment
solutions have a pH above 11.5.
It is possible but not necessary to treat the poultry, including eviscerated
and defeathered
poultry, with a blend of a major amount of trialkali metal orthophosphate and
a
corresponding minor amount of a basic agent, said blend being present in an
amount and
said poultry being treated for a time sufficient to remove, reduce or retard
bacteriological
contamination and/or growth on the poultry. The basic agent is used in the
blend in
amounts insufficient to cause substantial organoleptic depreciation of the
poultry. The
treatment solution has a pH above 11.5. The trialkali metal orthophosphate is
always
present per se or in a major amount of the treatment solution with the proviso
that alcohol
and ascorbic acid are never part of the treatment solution. Preferably, the
treatment time
is longer than about 5 minutes, if a dip solution application is used,
although much shorter
times have been found effective. We prefer to use the trialkali metal
orthophosphates per
se. In any case, from about 4% or more orthophosphate is used before chilling
the poultry.
Specifically, it has been discovered that poultry can be treated with a
solution containing
from about 4% to about saturation of orthophosphate in the aqueous solution.
Preferably,
about 4% to about 12% and most preferably about 8% or more trisodium or
tripotassium
orthophosphate dodecahydrate or an equivalent amount of the anhydrous
compound, is
effective. It has been found that treatment with the trisodium or tripotassium
orthophosphate gave essentially the same effectiveness as sodium hydroxide or
phosphoric
acid/sodium hydroxide without the adverse effects on the meat or skin which
accompany the
use of the sodium hydroxide or phosphoric acid/sodium hydroxide blend.
8
~:ipr 3 ~f211 ';o. ~B594190212L'S
2~.3'~~~~
By the use of this process, poultry carcasses can be washed economically and
simply with
food grade products to achieve bacteria reduction without organoleptic
depreciation of the
carcass. In addition, the shelf life of the final product can be increased by
between about
one and about fourteen days. Phosphate salts can remain on the poultry surface
to provide
S a surface less conducive to supporting bacterial growth, particularly in the
highly irregular
surfaces of the skin without fear of carcass degradation or impairment of
flavor.
Other benefits will become apparent from the description which follows.
DETAILED DESCRIP'1~ION OF THE INVENTION
Trialkali metal phosphate is an orthophosphate salt of the formula R3P04 with
a formula
for the sodium salt being Na3P04 and an equivalent formula for the
tripotassium
compounds. R is an alkali metal of sodium or potassium. Trisodium phosphate
has a
minimum of 41.5% P205 and a typical pH in a 1% solution of about 11.8.
Trisodium phosphate is also available as the dodecahydrate of the formula:
Na3P04 . 12H20
In commerce, the dodecahydrate is available in a technical grade with a
formula of:
5(Na3P04 . 12H20) NaOH;
or in the food grade with a formula of:
4 ( Na3P04 . 12H20 ) NaOH;
Both forms have a typical pH in 1% solution of 11.8. Preferably, the trisodium
phosphate
dodecahydrate (either form) is used. As used herein, trisodium phosphate is
intended to
include tripotassium phosphate as well as all forms of those compounds. Food
grade
9
_apr ~ _~Iail ':o. ~3594190212US
products are intended to be used for food uses.
This invention is applicable to all types of poultry including chickens,
turkeys, geese, capon,
Cornish hens, squab, ducks, guinea, fowl and pheasants. By poultry or carcass,
it is intended
to cover whole birds as well as parts.
The application of an aqueous trialkali orthophosphate solution of pH greater
than 11.5 is
made before chilling the carcass. We prefer to employ the orthophosphate
solution in a
manner which allows recovery of the solution after treating the poultry. The
recovered
solution is then filtered to remove insolubles and water and trialkali metal
orthophosphate
are added to maintain the concentration at an effective amount to remove,
reduce or retard
bacteriological contamination of the poultry. The poultry can either be
subjected to contact
with the treatment solution in a trough or may be subjected to solution
sprayed inside and
outside the poultry.
It is possible to employ a trough through which the poultry is transported by
chain shackles
or a spray through nozzles for from several seconds to minutes. Residual
treatment solution
remains after the actual contact with the poultry and such residual solution
is further
effective in removing, reducing or retarding bacterial contamination and/or
growth.
While treatment can be conducted at various places in the poultry treatment
process we
prefer several places where we can minimize the quantity of treatment solution
employed,
minimize the treatment time to that effective to produce the desired removal,
reduction or
retardation of bacteriological growth and/or contamination of the poultry.
After scalding the
poultry during feather removal we have found we may treat the poultry in a
trough for a
minimum of several seconds at a temperature of about 20 to 60°C prior
to the singe step
of processing. This helps reduce bacterial contamination. The treatment
solution is removed
in the subsequent washing step prior to evisceration. While it is possible to
treat with
orthophosphate during washing, the large quantity of water employed and
regulations
regarding the recycling of wash water preclude economical treatment. However,
treatment
:cpr s :fail :;o. LB594190212US
is possible either directly after washing and before evisceration or after
evisceration
preferably employing a spray treatment solution or drench system at a
temperature between
20 to 45°C. When treating after evisceration, it is possible to spray
the treatment solution
on the outside as well as the inside of the eviscerated poultry or to drench
the entire carcass
into a bath of treatment solution. Treatment can take several seconds or
longer with the
treatment solution remaining on the poultry until its introduction into the
chill tank. After
treatment, the carcasses maybe rinsed with water prior to chilling. The
treatment solution
is then recovered and recycled while solids are removed using filters and make
up water and
phosphate added to maintain orthophosphate concentration.
We have found that trace amounts of the treatment solution can remain on the
poultry (a
few hundredths of a percent) to further remove, reduce or retard bacterial
contamination
and/or growth of the poultry. Further treatments can be made after chilling
the birds and
when cutting and prior to packaging of the poultry using either a spray or dip
process.
We have found that anywhere from one second to two hours of treatment is
effective in
removing, reducing or retarding bacterial contamination, particularly
salmonella on poultry.
The time need only be an effective amount of time to produce the desired
result and can
easily be determined for this particular point in the process where treatment
is conducted.
By utilizing the pre-chill treatment, the shelf life of the final product may
be extended by
between about one and about fourteen days, with an extension of between about
three and
about five days being typical.
Equipment for recycling and removing solids is generally available from
manufacture of
meat pickling equipment. In general a rotary filter manufactured by Townsend
of Des
Moines, Iowa can be used to remove large particles while a screening system
also available
from Townsend can be used for smaller particle removal. The equipment should
be made
of stainless steel, plastic or other material resistant to the corrosive
action of trialkali metal
orthophosphate and acceptable for use in processing food.
11
_::~r ; :~=ail. ..o. ~3~9419021?IS
~1376~9
We prefer to employ saturated solutions of the orthophosphate which are highly
effective
in removing, reducing or retarding bacterial contamination. Saturated
solutions of up to 40%
are possible but usually from about 4%, preferably about 8% or 10% or greater
of trisodium
orthophosphate is effective. The phosphate may be combined with other
materials if desired
with the proviso that alcohols (ethanol or the like) and reducing agents like
ascorbic acid
are not employed. In other words the treatment solution does not contain
alcohol. We do
not employ any antibacterial which is detrimental to the organoleptic
properties of the
poultry such as high concentrations of sodium hydroxide or other harsh alkali
or alcohol. We
prefer to employ the trialkali metal phosphate per se to treat the carcass.
Dispersions of
orthophosphate can be used but appear to have little advantage over use of a
solution for
treating the carcass.
Where the chicken is additionally treated just prior to packaging, it is
possible to treat with
orthophosphate combined with other materials so long as alcohol is not
present. In
processing before or after evisceration but before cutting, we prefer to
employ trialkali
metal orthophosphate per se or at least with the proviso that alcohol is not
employed.
In spraying the treatment solution on the poultry we employ from 20 to 150 psi
to cause a
spray of medium particle size to impact the inside and outside of the poultry
with sufficient
force for good cleaning without any depreciation on the appearance or taste of
the poultry.
When treatment of the poultry occurs after defeathering and eviscerating, the
carcass is
washed with water or other acceptable cleaning solutions. Agitation,
sonification and other
mechanical means can be applied to assist in washing. Preferably, the carcass
is then treated
with a treatment solution containing from about 4% to about 12% and preferably
from
about 6% to about 12% and most preferably about 8% to about 12% by weight
trialkali
metal orthophosphate based on the weight of the solution.
The carcasses can be dipped in the treatment solution. If so, the carcass or
the solution is
preferably agitated to insure a good flow of the treatment solution over all
surfaces and in
12
~Yar s Mail :;o. 13594190212L'S
~l3~sz9
all crevices of the carcass. The treatment solution can also be applied by
mechanical
sprayers, preferably under high pressure to insure good contact. Soniflcation
may be
employed at either sonic or ultrasonic frequencies. Any other means of
contacting the
poultry with the treatment solution, such as in a rotating drum, can also be
used. The
poultry, optionally rinsed with water, is then forwarded for the usual chill
tank treatment.
The treatment solution preferably contains only trialkali metal
orthophosphate. The
treatment solution does not contain alcohol.
The treatment solution is preferably comprised only of trialkali metal
orthophosphate. For
purposes of adjusting pH, minor amounts of other agents can also be added.
These can be
illustrated by sodium carbonate, sodium and/or potassium hydroxide, alkali
metal
polyphosphate such as, sodium tripolyphosphate or acids such as phosphoric
acid. Since
hydroxides have an adverse effect on the organoleptic characteristics of the
poultry flesh,
it is preferred to avoid the use of these basic agents altogether or to use
amounts which
have no effect on the organoleptic characteristics of the poultry flesh. The
basic agent, if
used, is used in an amount insufficient with the alkali metal orthophosphate
to cause
organoleptic deterioration of the poultry flesh. By "minor amounts" is meant
less than 50%
by weight of the combined dry weight of the trialkali metal orthophosphate and
the basic
agent usually up to 45% and in all cases in an amount insufficient to cause
organoleptic
deterioration.
The ingredients in the treatment solution are used in amounts sufficient to
provide a pH of
above about 11.5 and preferably within the range from about 11.6 to about
13Ø The pH
level insures the treatment solution will remove, reduce or retard bacterial
contamination
or growth. We prefer to employ equipment which recycles the solution for
economy, filters
solids from the recycled solution for cleanliness, adds make up water to
maintain the
solutions volume and adds trialkali metal orthophosphate to maintain a
saturated or near
saturated solution. While a saturated solution insures maximum concentration
of the
phosphate, we have found that concentrations of about 4% to saturation and
more
particularly about 8% to near saturation are desirable. At cooler
temperatures, below 27°C
13
DI i :v211 ..J. i~594190212US
and 10°C a solution containing about 4% to about 12% trialkali metal
orthophosphate and
more preferably about 6% or more and most preferably about 8% or more is
effective to
reduce, remove or retard contamination and/or growth of all bacteria. At all
levels of about
4% or more trialkali orthophosphate, the pH will remain above about 11.5 and
preferably
from pH 11.6 to about 13.5, most preferably 12.0 to 13.5.
The poultry carcasses are contacted with the treatment solution for a period
of time
sufficient to reduce total aerobic bacterial contamination over and above that
obtainable
with pure water at temperatures ranging from about 20°C to 60°C,
and more preferably
between about 24°C and about 40 °C. Treatment dwell time is also
sufficient, under the
conditions of the treatment, to contact all contactable exposed surfaces of
the poultry
carcasses, effect a washing of the surfaces and thus contact substantially all
colony forming
units on the surface of the poultry. The contact time is sufficient to allow
upon drying, the
deposition of an even layer of trialkali metal orthophosphate on the exposed
surfaces of the
poultry to prevent or retard further bacterial growth.
At atmospheric pressure, in a dip tank, dwell times ranging from a few seconds
such as two
or more seconds after the scald tank and after about 30 seconds to about 30
minutes where
processing conditions permit have been found to be effective. Dwell times can
be reduced
using a pressure spray. Longer dwell times can be used if the solution
concentration is not
excessive.
Pressure spraying is particularly useful when both the inside and outside of
the eviscerated
poultry can be treated. We employ a rotating nozzle for the inside spray and
insert the
nozzle fully into the cavity resulting from evisceration so that all parts of
the exposed flesh,
tissue and bone is contacted with a spray of treatment solution. Outside
sprays are designed
to cover the total outside of the poultry. When treatment is employed after
poultry pieces
are cut, we employ a spray to cover all surface area. Where possible we allow
the treatment
solution to remain on the poultry to further reduce, remove or retard
bacterial
contamination and/or growth. Often we allow the solution to dry on the poultry
to further
14
:cp s 'Sail ':o. ~8594190212L'S
213'~62~
reduce, remove or retard bacterial growth.
The spray is propelled using from 20 to 150 psi pressure through spray nozzles
designed to
vigorously wash the surface without damaging the meat.
When using dip tanks or troughs the poultry is generally pulled through the
solution using
a chain and shackle system. Although this method, which permits the phosphate
treatment
solution to contact the entire poultry surface is suitable, agitation in such
tanks will improve
contact of poultry and solution and normally reduces the time of contact
required for good
results.
Immediately after treatment, the poultry can be processed following normal
processing
conditions such as draining and chilling. A unique feature of the invention is
the ability to
allow the trialkali metal phosphate to dry on the surface of the poultry
without the need to
wash.
While it is possible to treat the poultry at any point in the process before
chilling and at any
temperature and time which does not harm the product, we have identified
several areas
where we believe the treatment will be most effective. One or more treatments
with the
ZO alkali metal orthophosphate during processing are possible and often
desirable. Any
treatment temperature from 0 to 70°C for process times of several
seconds to hours
depending on the temperature is feasible.
After scalding and before defeathering, treatment provides a means of washing
undesired
?S contamination including bacterial contamination from the poultry as well as
providing a
coating of treatment solution on the poultry as it is exposed to defeathering
where further
bacterial contamination can occur. This treatment is conducted at 40 to
70°C, preferably 45
to 65°C for a short period of time.
30 It is also possible to treat the poultry after defeathering and before
evisceration although
~~~~~Ypr ~ Mail ';o. =°~~94190212t;S
we prefer to treat evisceration where both the inside and outside of the
poultry may be
thoroughly sprayed with treatment solution at 20 to 40°C, preferably 25
to 35°C. Particularly
good results are obtained by first applying a treatment solution on all
portions of the poultry
carcass, allowing the treatment solution to remain on the carcass for up to
one minute, and
then rinsing with water for up to another minute. The carcasses are then
chilled.
While the present invention is primarily directed at reducing salmonella
contamination of
the poultry, it is also intended to include all aerobic bacterial growth which
is affected by
the stated trialkali metal orthophosphates. In addition to salmonella, other
bacteria which
are measured by total plate count are significantly reduced. Because of the
high reduction
of total aerobic bacteria, the shelf-life of the poultry can be reduced by
between about one
and about fourteen davs.
Affected bacterial species can be easily determined by one of ordinary skill
and thus all such
bacteria as are affected are considered included in the invention.
The present invention will be illustrated in the Example which follows.
EXAMPLE
Eviscerated and defeathered turkeys are subject to one of three treatments to
determine the
effect these treatments have upon the reduction of aerobic bacteria, and in
turn, an increase
in the shelf life of the turkeys. The treatment conditions are as follows:
[A] - no treatment
[C] - the birds are drenched in a treatment solution for 15-30 seconds
containing a concentration of 10% trisodium orthophosphate
(AVGARD~ brand TSP, Rhone-Poulenc Inc.) at a temperature of 75 °F
(24°C)
[C'] - 20 seconds after contact with trisodium orthophosphate in accordance
16
~Ypr s :fail ::o. ~B594190212LS
~~.3 ~~~9
with treatment C, the birds are further rinsed with water for about 10
seconds.
These treatment conditions all occur prior to the turkeys being chilled.
Samples of each of
the turkeys are analyzed microbiologically for the following types of
bacteria: aerobic plate
count, enterobacteriaceae, E. coli and salmonella.
The tests are conducted for two consecutive days. The results from the Day One
testing are
shown in Tables 1, 2 and 3 and the results from the Day Two testing are shown
in Tables
4, 5 and 6.
17
:CDI 3 ::31i . .. _~ 94190212L'S
TABLE 1
SAMPLE APC E~TROBAC E. coli
# Col/gm ~ ~ol/ Col SALMON
/gm
VRHA+MUG E . C .
~ +~It7G ELLA
Presum~t. Conii~ed
1 I 1000 40 30 ~ 30 POSITIVE
~
2 ~ 32000 ~ 600 POSITIVE
1040 I
$00 I
3 I 000 ~ i30 80 _ POSITIVE
~ 80 '
4 ~ 6000 90 10 <i60 Neg
I
13000 i .90 ~ 90 9G Neg
6 I 10000 ~ I 520 ~ 520 POSITIVE
680
9000 ~ 100 30 30 Neg
8 18000 ~ 110 I 30 ~ 30 Neg
9 ~ 11000 360 ~ 360 Neg
j '~20
I 9000 i ~ 70 ( <10 I Neg
80
11 ~ 24000 ' 90 30 I Neg
j 100
12 I 12000 i 260 ~ 190 ~ 190 Neg
i
13 I 8000 i ~ 50 ~ 50 I Neg
60
14 I 9000 ~ ~ 170 I :.70 Neg
190
I 6000 ~ 150 ( ~0 ~ 60 I
N eg
I
18
213 ~ ~ ~ ~ =YPv S ='~ii ::o. 13594190212L:S
SAMPLE E.coli
# APC OHAC~ Col/ SALMON
9'~
Coi/gm Col/gm i
VRBA+MTJG E . C .
Pres +vItJG
um~ t .
Ccafiraed
16 I 16000 ~ 20 ~ lJeg
~0 ~ 20
I
17 ~ <1CC0 ~ <10 Neg
i lOQ ~ 20 I
~
18 I 6u00 ~ 140 130 ~ Neg
i 130 ~
i9 ~ 2000 54 ~ Neg
~ 50 ~
50 I
20 ~ 20000 720 ~ Neg
~ 440 ~
720 ~
21 I 11000 300 I 90 ,~0 I Veg
22 I 22000 , 120 110 110 Neg
23 I 9000 ~ 100 ~ 80 40 Neg
24 I 2000 50 i 40 40 Neg
25 ~ 12000 170 I 120 I I20 I Neg
26 I 16000 ~ 130 ~ 130 ( POSITT_V
~ 18p
27 ~ I5000
440 ~ 6
0 ~ Q 0
~ leg
28 2000 ' 120
i 190 ~
190 ~ Neg
29 ~ 10000 320 ~ 180 I 180 ~
Neg
30 ( 10 0 0 ~ 150 I SO I Neg
0 ~ 160
19
9 _::~r :~_aii : ,.. =3~9~ 19021=CS
TABLE 2
SAMPLE # APC I E. g
ENTROHAC coli
Coi/gm Col/gm Col/gm
C
VR~ATMUG .C.-MUG
~
I Presuma~.Cor:fir~ed
i
1 ~ 20C0 ~ ~ <1C ~ Neg
<! -
0 ~
2 I 3400 i ~ <LO - Neg
<Lp I
i 3 ~ ?00 ~ I <Lp ~ Neg
<LO -
I
4 I X400 I <10 ~ <1C ~ Neg
-
I
I X00 ~ <IO ~ <10 ~ Neg
-
I
500 I <i0 ~ <10 I Neg
-
800 I <10 I <LG ~ Neg
-
I
8 ~ 3000 f <LO ~ <i0 ~ Neg
-
I
9 ( 1100 ~ I <i0 ~ Neg
<LO -
I
1G . ~ 300 I I <iu ~ Neg
<i0 i
11 I 2600 ~ <i0 ~ <10 ~ Neg
-
I
12 I 6000 <1Q ~ <LO ~ Neg
-
I
j 13 '3200 ~ ( <r 0 j ,beg I
<10 I _
~
14 ~ i300 I <LG ~ <i0 ~ Neg
-
I
i 15 6400 ~ <i0 i~ Neg
<LO
:iD S :'foil :.J. .. 5q~+l9GZl~t,$
TABLE 3
SAMPLE ~ E. coli
APC "r..TIT~OHAC Co 1 / gm S
Col/5~.n
, Coi/gm UREA+~iUG
I I .C -
MUG
Presumpo.
i Coasiraed
1 ~ <LOG Neg
<LO ~ <~.p
~ - ~
Z ( 400 ~ <IC <10 ~ - Neg
~ ~
3 ~ <100 <10 <1C ~ - Neg
~
4 ~ <100 I <10 <10 ~ -
~ ~ Neg
S I <1C0 ~ <10 I <10 - ~ Neg
500 ~ <10 I <10 I - I Neg
L30G ~ <10 I <10 ~ Neg
- I
<L00 ~ <10 I <1C - I Neg
~ ~I00 ~ I <1~ ~ ( Neg
<i0 -
J
's00 ~ <10 I <1C ~ I Neg
-
11 ~ 300 ~ <10 I <IO ~ - ~ Neg
i '~ ~ <100 ~ <LC~ ~ -
<10 I Neg
13 <100 p <10 ~ <10 -
( Ne
9
14 ~ 2700 ~ ~ <10 !
<10 - ~ Neg
1J ~ 54CG i I <LO -
<10 Neg
E
21
~:cpr~ _:aii :;o. _3594i9021~L.'S
TABLE 4
S~~ E. coli
ENTEAOHAC Col/gm SALMiON
Col/gm Col/gm
Vr'~HA+~ILTGE . C .
Presume -iHUG
t . I Confi wed
I
31 I 4000 ~ X80 I 140 140 POSITIVE
i 32 ~ 4000 ~ 13G 70 70 I POSITIVE
I 33 I =000 220 220 I Neg
~ 's60
I
34 I L0000 ~
100 50 I 50 ( POSITIVE
35 I 11000 110
I 15 0 I i. 5 0 Neg I
36 26000 ~ 520 I 440 440 pOSIT~
I
37 5000 I 240 I 240 I 240 I POSITIVE
38 11000 I 1160 520 520 Neg
39 9000 2480 i 1520 1520 Neg
40 2000 220 100 SO I Neg
41 I 12000 I 170 26G I 260 I Neg
42 I LOOOC I 1~.0 I fi0 Neg
~ 230
43 I
' 36000 ~ I 1280 i2a(~ Neg
1720
44 13000 ~ I 170 I 170 I Neg I
X50
45 9000 i 250 I 150 ~0 ( ;leg
22
-::p .. 'fai_ ., .. =SS9:~i9021='.:S
SAMPLE # APC F~TEROBAC E. SALi~J
coli
Col/gm Col/gm Col /gm ELLA
VttBA+yiUG E
.
C
.
+rvItTG
dl
Presumpt. Can=iz~e
46 8000 1400 540 640 :leg
~
47 I 21000 ~ ,$60 I ~ POSITIVE
30 80
(
48 L4000 ~ =~JO ~ I Neg
580 680
I
49 ~ L~~300 ~ $20 ~ I Neg
96G 60
~
i
50 I 34000 ~ 250 ~ I leg
. 5O 100
~
5~ 8000 ~ 100 ~90 30 Neg
I
52 ~ %6000 I 360 ~230 230 Neg
~3 15000 ~ 160 ~120 I Neg
120
I
54 11000 ~ 50 60 ~ Neg
<10
55 ' 54000 1420 I1040 1040 Neg
56 I ? 1 6000~ 920 ~500 ~ leg
250
i 57 I 26000 ~ 280 I260 160 I Neg
58 4000 ~ X60 ~320 ~ ~ Neg
'320
-59 ~ L8000 ~ 320 ~ ~ ~ Neg
160 L6v
6O 6OOO ,
280 ~ ~ ~ leg
220 220
__:..._ _.___ : _. ;_~'~1~~0~___'c
~1~'~~2~
TABLE 5
I SAMPLE I ENTEROBACE. coli SALMI
# APC ' I
Col/gm Col/gm ~ Col/gm ELLA
i
C ~ ~EFt~t,TG ... . -~JG
~
~ Ccnsi~ed
2resumao.
16 ~ E00 ~ <10 ~ <10 ~ Neg
- ~
17 I L60~J ~ <.10 i <1Q ~ Neg
- ~
18 ~ 1600 ~ <10 ~~ <IO ~, ~e9
- ~
19 ~ X400 ~ <i 0 ~ <10 - ~ Necr
~
20 - ~ 1200 <10 ~ <10 ~ - I Neg
21 2800 <IO ~ <10 j - Neg
22 3200 <i0 <10 i - ~ POSITIVE
!i 23 300 ~ <i.0 ~ <i0 ~ - ' leg
24 I 2400 I <LO I <i0 ~
- ~ Neg
'~ 25 ~ L1300 ~ ~ 1C ~, ~ 10 ~' - ~ Neg
I 26 , 2800 ~, ei0 ' -
<LO ~ I Ne9
7 ~ X800 ' <~.0
~ <lg '
- I Ne9
28 ~ <200 ; <10 <?0 ~ - ~ Ne9
~
29 I i12v0 <10 I <i0 ~ Neg
I - I
30 ( 3200 I ~ <Z3 ~
<i0 - I beg
I
'_' 4
.'"' ___ =s _'.~i~ .,.,. 359=X9021=:.'S
z~~~~z~
TABLE 6
SAMPLE # APC I ENTROHAC ~ SALI~1
E.
coli
C O 1 / C C ELLA
Cwt O O
1 1
/ /
gilt glll
C t
VRaAtLrIUG
~
E
.
C
.
-MUG
PrestJmpt.
~
Ccnf~r~ed
L5 I L400 ~ ~ Neg
<10 <~.0
~
-
~
L7 ~ 2200 ~ ~ Neg
<i0 <10
~
-
I
18 I X00 ~ I - I Neg
<i0 <i0
~
i9 500 ~, ~ - I Neg
<10 <i0
I
20 <100 ~ ~ - Neg
<10 <10
I
21 L400 ~ ~ Neg
<10 <10
'
-
22 ~ <100 <10 <10 ~ - Neg
23 I 800 ~ I<10 ~ - Neg
<10
24 I 2500 ~ ~<10 ~ - Neg
i <IO
25 ~ <100 ~ I Neg
<10 <lQ
I
-
~
26 ' 2800 <i0 I ,1e
<iQ g
I
-
I
~7 <i00 <i0 j Neg I
<LO
I
-
~
28 1800 ~ I Neg
<10 <LO
-
29 500 ~ , I Neg
<10 <10
~
-
30 2400 ~ <10 I <10 - Neg
i
I
_ ~~~__. _ ..___ . _. _JJ _
237
The Treatment A data for Day One are typical and exhibit a 17% (5/30)
incidence rate for
Salmonella. In contrast, the treated samples identified as [C] are all
negative for
Salmonella, as well as E. coli and enterobacteriaceae. In addition, these
samples exhibit
reduced Aerobic Plate Counts by about one log order of magnitude. The sample
identified
as [C'] (drench/rinse) have the same negative incidence for Salmonella, E.
coli and
Enterobacteriaceae. It is noted that the Aerobic Plate Counts are further
reduced by the
rinse after treatment, such that the incidence rate at the level of detection
for samples
evaluated in this group is reduced to 47% (8/15). This lower order of
magnitude for
Aerobic Plate Count is further evidence of the effect of a prechill
drench/rinse paradigm.
This reduction can translate into a shelf life extension ranging from about
one to about
fourteen days.
Similarly, on Day Two the untreated samples identified as [A] exhibit a
Salmonella
incidence rate of 20%, or 6 out of 30. The subsample identified as [C] are
taken as in the
prior day one minute from contact time, after drainage, exhibits one positive
out of 15.
There is a rationale for this positive, namely the potential for cross
contamination with
untreated carcasses. However, the E. coli and Enterobacteriaceae levels are
all negative for
this group, and the Aerobic Plate Counts are also similarly reduced.
Lastly, the subsamples identified as [C'] are all negative for Salmonella, E.
coli and
Enterobacteriaceae, with a similar reduction in terms of negatives for Aerobic
Plate Count
at the level of detection of 100 colonies per gram. In this instance there are
4 out of 15
negative, or a 26.6% incidence reduction in Aerobic Plate Counts. Again, this
can translate
into an increased shelf-life of from one to fourteen days.
These data, therefore, dramatically demonstrate the optimum effectiveness of
the trisodium
orthophosphate treatment, namely a drench only system either alone, or with a
post drench
water rinse to further reduce to the lowest level possible the incidence of
pathogens on
these treated carcasses.
26
_.;D' .. .=311 ..J. _WQ1 t y~~l-:.~5
2.~~ l ~3w.
Having described the invention in detail and by reference to the preferred
embodiments
thereof, it will be apparent that modifications and variations are possible
without departing
from the scope of the appended claims.
27
