The present invention relates to an improved process for reducing
the level of and retarding the growth of bacteria, such as salmonellae, during
processing edible animals and bacterial present on animal carcasses without causing
organoleptic depreciation thereof.
Animals including poultry of all types, red meat animals of all kinds,
fish and crustaceans and the like are killed and processed for human consumption.
Usually inedible parts are removed by evisceration which can cause contamination
of the edible portion of the animal with unwanted bacteria. Bacteria, naturally
present on and in the animal often remains and may multiply depending on the sanitary
conditions employed in processing.
Poultry is processed, after slaughtering, by scalding to assist in
defeathering, defeathering usually by machine, washing, eviscerating and chilling
prior to packing. These treatments are controlled to avoid causing a change in
the appearance or characteristics of the poultry which would make it unsalable.
In processing fish, fish are taken from the ocean or fresh water
and eviscerated often with filleting. In this process the fish can become contaminated
with certain bacteria or may naturally have such bacteria on the skin. Crustaceans
are often just cooked and the shell removed.
Red meat is processed by removing the hide, eviscerating, cooling
and cutting into larger cuts for fresh, cured meat or boxed meat. The fresh red
meat obtained after evisceration is chilled by hanging the sides of red meat at
a temperature usually below 10°C. Beef is hung for a considerable period to allow
natural enzymes to tenderize the beef. Pork is simply cooled. For certain primal
cuts, such as ham, bacon, corned beef and pastrami the cuts are cured by chilling
below 10°C, followed by injection of a solution containing salt, nitrite and/or
nitrate, sweetener, cure accelerator, one or more polyphosphates, spices and flavorings.
The meat is prepared to 105% to 130% of its weight with curing solution. Boxed
meat is cut into primal cuts after chilling, vacuum packaging and boxing.
Animals, after eviscerating, often show high levels of bacteria on
the surface of the carcass. A large part of carcass contamination can be removed
by water washing. While bacteria can be killed by heat, such as during cooking,
colony forming units of bacteria can attach and/or reside in the regular and irregular
surfaces of the flesh and 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 economical
systems for reducing bacteria contamination of animal carcasses without causing
A treatment system must be economical, easy to use, compatible with
food manufacturing and not change the organoleptic properties of the animal. Any
change in the appearance or flavor of the animal would make it unsalable.
Extensive research conducted by the prior art has been unsuccessful
in providing a treatment to reduce bacteria levels of animal carcasses without
causing extensive organoleptic depreciation.
The invention provides an animal carcass wash process which removes
or reduces existing bacterial contamination, as well as retards further contamination
or growth without affecting the organoleptic properties of the poultry carcasses.
In accordance with the present invention, there is provided a process
for treating animal carcasses to remove or retard bacterial growth, without affecting
the organoleptic properties of the animal carcasses.
More particularly, the present invention relates to a process for
treating the surface of animal carcass with an aqueous treatment solution having
a pH above about 11.5, said solution containing trialkali metal orthophosphate
present in an amount effective to remove, reduce or retard bacterial contamination
It has been discovered that during processing from about 4% or more,
and up to saturation, preferably 8% or more, trialkali metal orthophosphate may
be added to processing water at any point in the process to elevate the treating
solution to above pH 11.5 and remove, reduce or retard bacterial contamination
and/or growth on the surface of the animal carcass. In processing, we prefer to
use the aqueous phosphate water solution to surface treat the animal carcass at
places in the treatment process where the treatment solution can be filtered and
recycled with make up water to maintain the orthophosphate concentration at above
about 4% and the pH above 11.5.
For 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 hot solution and
recycling the solution with filtering to economically utilize the phosphate. We
most prefer, however, to treat the poultry after the chill tank particularly using
an inside/outside wash. After the chill tank, we treat with a cold orthophosphate
solution generally below 10°C. It is also possible to treat the poultry after cutting
and prior to packaging with cold orthophosphate solution.
For red meat, the process comprises surface treating the red meat
carcasses, preferably prior to rigor, by contacting the surfaces with a solution
of trialkali orthophosphate above pH 11.5 without appreciably changing the color
of the meat by causing a darkening of the muscle tissue resulting from high pH.
By contacting the red meat prior to rigor, however, lactic acid produced during
rigor partially or totally neutralizes the trisodium orthophosphate and further
reduces any adverse pH effect on color. Alternatively, a water and/or acid wash
may be employed to neutralize any orthophosphate remaining on the surface after
The treatment is preferably conducted during slaughter either prior
to or after chilling by dipping or preferably spraying the orthophosphate solution
onto all surfaces of the carcass for several minutes. Preferable treatment is
done before rigor on set.
In treating raw fish and/or crustaceans, we treat the surface of
the fish, just after evisceration with a treatment solution above pH 11.5 which
comprises about 3%, preferably from about 4% to saturation of a solution of the
alkali metal orthophosphate, for a period of time effective to reduce, remove
or retard the growth of seafood microorganisms.
It is possible, but not necessary, to treat the animal with a blend
of a major amount of trialkali metal orthosphosphate 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 animal carcass. The basic agent is used in
the blend in amounts insufficient to cause substantial organoleptic depreciation
of the poultry. The trialkali metal orthophosphate is always present per se or
in a major amount of the treatment solution with the proviso that alcohol is never
part of the treatment solution.
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.
By the use of this process, animal carcasses can be washed economically
and simply with food grade products to achieve bacteria control without organoleptic
depreciation of the carcass. Phosphate salts can remain on the animal surface
to provide 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.
Trialkali metal phosphate is an orthophosphate salt of the formula
R&sub3;PO&sub4; with a formula for the sodium salt being Na&sub3;PO&sub4; and an
equivalent formula for the tripotassium compounds. R is an alkali metal of sodium
Trisodium phosphate is also available as the dodecahydrate of the
Na&sub3;PO&sub4; . 12H&sub2;O
In commerce, the dodecahydrate is available in a technical
grade with a formula of:
5(Na&sub3;PO&sub4; . 12H&sub2;O) NaOH;
or in the food grade with a formula of:
4(Na&sub3;PO&sub4; . 12H&sub2;O) NaOH.
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 products are intended to be
used for food uses.
The invention is applicable to any edible animal material which is
not vegetable or mineral and can include poultry, fish and crustaceans and red
meat animals. By carcass, herein, we mean the edible remains of any dead animal.
The invention is applicable to all types of poultry including chickens,
turkeys, geese, capon, cornish hens, squab, ducks, guinea, fowl and pheasants.
The invention is applicable to fish or crustacean from salt or fresh
water either in whole, eviscerated, or filleted condition including bony and cartilaginous
fish such as flounder and shark respectively; fresh water fish such as trout;
salt water fish such as grouper; mixed water fish such as salmon and the like.
Fishes also includes aqua cultural fish such as catfish.
Crustaceans that can be treated include crayfish, prawns, crabs and
lobsters both aquacultural and wild and caught from either a fresh, brackish or
salt water habitat. Fish and crustaceans also include bivalve shellfish such as
scallops, oysters and mussels, as well as, mullusks such as conch. Also included
are other marine species such as squid.
The invention is also applicable to any red meat including pork,
beef, veal, mutton, lamb and goat either whole carcass or fresh parts, preferably
before rigor and at least treated before appreciable color change is evident from
The application of an aqueous trialkali orthophosphate solution of
pH greater than 11.5 can be made at any point during processing. We prefer, however,
to employ the orthophosphate solution in a manner which allows recovery of the
solution after treating the animal. The recovered solution is then filtered to
remove insolubles and water and trialkali metal orthophosphate added to maintain
the concentration at an effective amount. The animal carcass can either be subjected
to contact with the treatment solution in a trough or may be subjected to solution
sprayed inside and outside the carcass depending on where in the process treatent
is made. The animal may be treated at several points in the process. For fish or
crustaceans it is possible to treat at point of catch using fresh or seawater
having the orthophosphate added thereto.
It is possible to employ a trough through which the animal is transported
by chain shackles usually a 5 second to 30 minute dip or a spray through nozzles
for from several seconds to minutes usually 2 seconds to 15 minutes, usually,
less than 30 seconds. Residual treatment solution remains after the actual contact
with the animal and such residual solution is further effective in removing, reducing
or retarding bacterial contamination and/or growth.
For poultry, while processing treatment can be conducted at various
places in the 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 50°C-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
is possible either directly after washing and before evisceration or after evisceration,
preferably employing a spray treatment solution at a temperature between 20°C 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. Treatment
can take several seconds or longer with the treatment solution remaining on the
poultry until its introduction into the chill tank. It is also possible to employ
a post chill treatment with trialkali orthophosphate solution maintained at below
27°C, preferably below 10°C. The solution may be applied in a trough or tank but
is preferably sprayed on the inside and outside of the poultry. 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.
Red meat is treated with trialkali metal orthophosphate. For cured
meat the meat is treated prior to pumping cuts of meat with salts, nitrate and
the like. The trialkali metal phosphate treatment prevents bacteria from being
driven into the meat during pumping which could result in later spoilage. By treating
the surface first with orthophosphate any bacteria are removed or controlled prior
to the pumping operation.
Immediately after treatment the meat can be processed by usual meat
If a high level of orthophosphate is present which could cause discoloration,
then the red meat must be treated with water and/or a dilute acid to adjust the
meats pH. However, if treated before rigor, the lactic acid generated from rigor
assists in controlling the browning of the muscle meat.
We have found the trialkali metal orthophosphate is effective against
salmonella, campylobactar, listeria, spoilage bacteria and the like.
The treatment solution preferably contains only trialkali metal orthophosphate
as the means to control, reduce, retard or remove bacteria. No alcohol, nitrate
or nitrite, or ascorbic acid is employed in the treatment solution for purposes
of enhancing the effect of the orthophosphate. The treatment solution may contain
other ingredients for water binding, cleaning, flavoring, coloring and the like.
Salts may be used, including chlorides and the like. Normally, except in pumping
solutions, other phosphates are not combined with the orthophosphates.
Fish and crustaceans can be treated with the trialkali metal orthophosphate
at any stage of processing, such as during shell, skeleton, head, viscera, scale
or skin removal or prior to, during or after freezing, refrigeration, icing, ice
glazing, cooking or pasteurization. Preferably the fish and crustaceans are treated
either just after catch on the fishing boat or shortly after arrival at the processing
plant prior to cooking or packaging.
After the fish or crustacean is caught it is eviscerated, often skinned
or filleted and washed with water or other acceptable cleaning solutions. Agitation,
may be applied to assist washing. Before, concurrent with or after the washing
the fish or crustaceans are treated with a treatment dispersion or preferably a
solution containing about 3% preferably from about 4% to saturation of trialkali
metal orthophosphate. The fish or crustaceans can be dipped in the treatment solution
with agitation to insure contact of the treatment solution with all surfaces and
crevices of the fish. The treatment solution is preferably applied by mechanical
sprayers, under high pressure to insure good contact of treatment solution with
the fish surface.
The treatment solution preferably contains only trialkali metal phosphate
as the means to control, reduce, retard or remove bacteria. No alcohol, ascorbic
acid or other phosphates except those present in salt water at about the concentration
present in salt water are employed in the treatment solution. The treatment solution
may contain other ingredients for preservation, water holding, cleaning, flavoring,
coloring, including salts such as sodium and potassium chlorides and the like.
Often the solution may be prepared from salt water. In the treating the fish or
crustaceans, the solution comprises trialkali metal orthophosphate with the proviso
that it contains no alcohol, ascorbic acid or other phosphates.
The treatment solution for all animals preferably contains the orthophosphate
in an amount sufficient to provide and maintain a pH above about 11.5 and preferably
within a range from 11.6 to 13.5 and most preferably from pH 12.0 to 13.5.
We have found that trace amounts of the treatment solution can remain
on the animal carcass (a few hundredths of a percent) to further remove, reduce
or retard bacterial contamination and/or growth on the carcass surface. A further
treatment can be made after cutting and prior to packaging of the animal using
either a spray or dip process.
We have found that anywhere from several seconds to hours of treatment
is effective in removing, reducing or retarding bacterial contamination. 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
At atmospheric pressure, in a tank or other dipping device, dwell
times at 5 seconds to about 30 minutes are effective while dwell times using a
spray range from several seconds to several minutes or 2 seconds -15 minutes with
spray times of less than 30 seconds preferred.
A high pH maintained at over 11.5 preferably 12.0 or greater is critical
to remove, reduce, retard or control bacterial contamination and/or growth. The
mechanism is not entirely understood but the orthophosphate treatment appears
to improve bacteria removal as well as retarding growth of any residual bacteria.
Equipment for recycling and removing solids is generally available
from manufactures 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 for stainless steel, plastic or other material
resistant to the corrosive action of trialkali metal orthophosphate.
We prefer to employ 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 greater up to saturation of trisodium orthophosphate is effective. The phosphate
may be combined with other materials if desired with the proviso that alcohols
(ethanol or the like) reducing agents like ascorbic acid other phosphates with
fish and nitrates and nitrites with red meat are not employed. We do not employ
any antibacterial which are detrimental to the organoleptic properties of the animal
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 animal is 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 animal we employ from 20
to 150 psi to cause a spray of medium particle size to impact the inside and outside
of the carcass with sufficient force for good cleaning without any depreciation
on the appearance or taste of the animal.
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 an/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 animal 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 flesh. The basic agent, if used, is used in
an amount insufficient with the alkali metal orthophosphate to cause organoleptic
deterioration of the flesh. By "minor amounts" is meant less than 50% by weight,
preferably less than 45% of the combined dry weight of the trialkali metal orthophosphate
and the basic agent and in all cases in an amount insufficient to cause organoleptic
At all levels of about 4% or more trialkali orthophosphate, the pH
is maintained above about 11.5 and preferably from pH 11.6 to about 13.5, most
The treatment is conducted under good animal processing conditions.
Cool temperatures and cool treatment solutions are used after chilling the eviscerated
animal to avoid undue deterioration of the carcass. The treatment solution temperature
is preferably less than 27°C, more preferably less than 10°C.
The carcasses are contacted with the treatment solution for a period
of time sufficient to reduce bacterial contamination over and above that obtainable
with pure water. Treatment dwell time is also sufficient, under the conditions
of the treatment, to contact all contactable exposed surfaces of the carcasses,
effect a washing of the surfaces and thus contact substantially all colony forming
units on the surface of the carcass. 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 carcass 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 about 30 minutes, where processing
conditions permit, have been found to be effective. Dwell times can be reduced
using a pressure spray to 2 seconds to 15 minutes. 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 animal such as 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 carcass. Where possible we allow the treatment solution to remain
on the surface to further reduce, remove or retard bacterial contamination and/or
growth. Often we allow the solution to dry on the surface to further 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 animal is generally dipped in
or pulled through the solution. Although this method, which permits the phosphate
treatment solution to contact the entire surface is suitable, agitation in such
tanks will improve contact and normally reduces the time of contact required for
Immediately after treatment, the carcass 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 carcass without the need to wash. The residual phosphate left
on the animal particularly poultry surface provides reduced bacteriological activity
particularly in the cracks and pockets of the skin and flesh.
It is possible to treat the animal at any point in the process and
at any temperature and time which does not harm the product. One or more treatments
with the alkali metal orthophosphate during processing are possible and often
desirable. Any treatment temperature from 0-70°C for process times of several seconds
to hours depending on the temperature is feasible.
In treating poultry the orthophosphate solution may be applied after
scalding and before defeathering, treatment provides a means of washing undesired
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
40-70°C, preferably 45-65°C for a short period of time.
It is also possible to treat the poultry after defeathering and before
evisceration although we prefer to treat after evisceration where both the inside
and outside of the poultry may be thoroughly sprayed with treatment solution at
20°- 40°C, preferably 25-35°C and allow the treatment solution to remain on the
bird entering the chill equipment.
It is also preferred to treat the poultry post-chilling with a treatment
spray inside and outside of the poultry. This step helps remove any undesired material
present in the chill tank and treats any additional bacteria which may have contacted
the poultry in the chill tank. Again, we prefer to allow the solution to remain
on the poultry including cutting and after packaging. Where cutting of the processed
poultry is done, we can treat the cut poultry with trialkali metal orthophosphate
solution and then wash the poultry or pack the parts as is.
Leaving the treatment solution on the carcass provides a further
opportunity to remove, reduce or retard bacterial contamination and/or growth on
the surface including packaged animal flesh.
While the present invention is primarily directed at reducing salmonella
contamination of meat, it is also intended to include all bacterial growth which
is affected by the stated trialkali metal orthophosphates. In poultry this includes
E. coli, Entarobacteriacae, campylobacter; on fish and crustaceans Pseudomonus
aeruginosa, Bacillus cereus, Moraxella osbersis, and for red meat campylobacter
and listeria. In addition to salmonellae, spoilage bacteria and other bacteria
which are measured by total plate count are significantly reduced.
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
The present invention will be illustrated in the Examples which follow.
The poultry used in the Examples 1-13 are conventional chicken broiler stock weighing
dressed from about 0.9 to about 1.1 kilograms.
Grade A broilers from a processing plant after rinsing and before
being chilled in the chill tank were packed in coolers with "CO&sub2; snow", transported,
separated and placed on ice and kept in a 1.1°C (34°F) cooler overnight. The birds
were dipped for 1 minute in an inoculum of 10&sup7; - 10&sup8; CFU/ml of a freshly
grown nalidixic acid resistant strain of Salmonella typhimurium harvested
from BHI broth and then allowed to drain for a specific time. After the allotted
draining time, 5 broilers were submerged and agitated in each treatment solution
for a specified dwell time. Each agent was placed in a separate tared clean plastic
container. Water and ice were added until 20.4 kilograms was obtained with a temperature
of approximately 7.2°C (45°F) One inoculated broiler was immersed in water as
control and one inoculated bird was retained without washing as a control.
After treatment, the birds were individually placed in Cryovac plastic
bags and were either analyzed immediately (two birds plus the inoculated control)
or placed in a 2.2°C (36°F) incubator to determine the effect of treatment after
storage. Two broilers were analyzed for each treatment after 5 and 8 days storage
at 2.2°C (36°F). Thus seven birds were used for each treatment. The following
conditions were used:
Example Treatment Agent Amount /20.4 Kg Inoculum Drain Time Treatment Dwell Time 1Na&sub3;PO&sub4;2.4 kg2 minutes30 seconds 2Na&sub3;PO&sub4;0.78 kg1 hour15 minutes 3Na&sub3;PO&sub4;1.6 kg2 minutes15 minutes 4Na&sub3;PO&sub4;1.59 kg1 hour15 minutes 550% Na&sub3;PO&sub4;1.59. kg1 hour15 minutes *50% STP 6Water0.02 minutes15 minutes
* STP means sodium tripolyphosphate
ENUMERATION OF NALIDIXIC ACID-RESISTANT SALMONELLA
Nalidixic acid-resistant salmonellae were enumerated using the whole
carcass wash procedure as prescribed by the National Broiler Council. Each bird
was weighed and the resulting weight was divided by 3.8 to determine the number
of ml of lactose broth plus 0.6% tergitol to be added to the bag. The bird, broth,
and bag were shaken for 1 minute through an arc of 2 ft in a manner assuring that
the broth flowed through the abdominal cavity and over the entire surface of the
carcass. Serial dilutions of this broth in Butterfield's buffer were plated using
the pour plate procedure with MacConkey's agar with 100 ppm nalidixic acid added.
These plates were incubated for 48 hours at 35°C then counted. Nalidixic acid-resistant
colonies were selected and confirmed as Salmonella using FDA Bacteriological
Analytical Manual (BAM) Procedures.
As a backup procedure to assure recovery of sublethally injured nalidixic
acid-resistant salmonella, a 10 ml aliquot of the lactose broth, 0.6 percent tergitol
carcass wash was pipetted into a sterile culture tube and incubated for 24 hours
at 35°C. In the event that no growth occurred on the MacConkey Agar/nalidixic acid
plates, the backup wash was examined for the presence of salmonellae using FDA
The results achieved are shown in Table II which follows. The data
for storage at 2.2°C (36°F) for 0, 5 and 8 days, is compared to an inoculated control
which has been washed only with water.
DISCUSSION OF RESULTS
The inoculum suspension averaged 1.6 x 10&sup8; CFU per ml nalidixic
acid-resistant Salmonellatyphimurium. Uninoculated, untreated control
broilers averaged 380 nalidixic acid-resistant salmonellae per ml. This number
is considered insignificant in light of the inoculum level used in the experiment.
Untreated inoculated controls averaged 1.2 x 10&sup7; CFU per ml nalidixic acid-resistant
Treatment of inoculated carcass with water wash only (Example 6)
gave reductions of 90.9 to 95.1 percent (approximately 1 log-cycle). Therefore,
the water rinse by itself removed approximately 90 percent of the nalidixic acid-resistant
The treatments of Examples 1 and 2 both gave reductions in the 99
to 99.9 percent range (2 to 3 log cycles). Thus the higher concentration and short
dwell time of the treatment of Example 1 was approximately equivalent to the lower
concentration longer dwell time of the treatment of Example 2.
The treatments of Examples 3 and 4 both gave 99.999 percent (5 log
cycle) reductions immediately after treatment (Time 0) as compared to inoculated
untreated controls. However, reductions were 99.98 or 99.99 (approximately 4 log
cycles) for samples stored for 5 or 8 days at 3.3°C (38°F). This may indicate that
injured cells not recovered by plating immediately after treatment may be able
to effect repair during refrigerated storage. The increased recovery numbers do
not indicate growth since salmonellae will not grow at temperatures less than 7.2°C
The treatment of Example 5 gave a reduction of 99.9998 (nearly 6
log-cycles) immediately after treatment. Again, there was increased recovery of
nalidixic acid-resistant salmonellae at 5 and 8 days compared to immediately after
Broilers randomly selected from the chill tank and transported on
wet ice were treated as in Example 1. Seven treating solutions were prepared, 3
as per the invention and 4 controls. Eleven chickens were dipped at one time in
the inoculum for 1 minute and allowed to drain for a specific time. Ten of these
broilers were submerged in a specific agent for the time given in Table III. One
inoculated broiler was retained as an inoculated untreated control. The birds
were placed in Cryovac bags and stored as in Example 1. Duplicate broilers were
analyzed for each treatment after 5 and 7 days storage at 2.2°C (36°F) and after
3 and 5 days storage at 12.8°C (55°F). Enumeration of salmonellae was as described
in Example 1. The following conditions were used:
* Examples 11
and 12 were run using two separate baths and two separate dwell times as listed.
The results are shown in Table IV.
The untreated controls were prepared by dipping the carcass in inoculum
and draining for the same period as the treated sample. The enumeration of nalidixic
acid-resistant salmonellae was conducted without storage.
Percentage reductions of nalidixic acid-resistant salmonellae due to various
treatments¹ followed by storage at 2.2°C for 0, 5,
and 7 days. Compiled from Table IV. Time (Days)0000000 Example10811791213 Pct. Reduction99.999799.999399.999099.99799.99199.98792.777 Time (Days)5555555 Example97812101113 Pct. Reduction99.99399.6999.36694.8342.2735.71- Time (Days)7777777 Example91171210138 Pct. Reduction99.999699.991999.98599.3498.0495.8390.66
listed in descending order of effectiveness for a given storage time.
Efficacy of treatments of Examples 7 through 13 against a nalidixic acid-resistant
inoculated onto fresh broiler carcasses held
at 12.8°C. Example 12.8°C Storage Time (days) Replicates Mean of 2 dup. CFU per ml. Mean CFU per ml Log CFU per ml Pct. Reduction 732.9 x 10&sup5;2.9 x 10&sup5;2.9 x 10&sup5;5.4699.55 56.85 x 10²2.45 x 10&sup6;1.2 x 10&sup6;6.0998.15 836.95 x 10&sup4;1.9 x 10&sup4;4.4 x 10&sup4;4.6599.85 51.02 x 10&sup6;2.05 x 10²5.1 x 10&sup5;5.7198.3 932.35 x 10²3.95 x 10&sup4;2.0 x 10&sup4;4.3099.947 51 x 10¹1 x 10¹1.0 is 10¹199.999 1031.11 x 10&sup6;2.7 x 10&sup6;1.9 x 10&sup6;6.2898.04 54.57 x 10³1.9 x 10&sup5;9.7 x 10&sup4;4.9999.9 1133.65 x 10&sup6;2.45 x 10&sup6;3.1 x 10&sup6;6.4892.62 57.95 x 10³8.55 x 10²4.4 is 10³3.6499.989 1232.3 x 10&sup4;6.0 x 10&sup5;3.1 x 10&sup5;5.4998.93 56.3 x 10²3.95 x 10²5.1 x 10²2.7199.998 1336.7 x 10&sup6;5.85 x 10&sup6;6.3 x 10&sup6;6.8082.5 52.5 x 10&sup6;1.1 x 10&sup7;6.75 x 10&sup6;6.8381.1
Percentage reductions¹ of nalidixic acid-resistant
salmonellae due to various treatments² followed by storage
at 12.8°C. Complied from Tables IV and VI. Time (days)0000000 Example10811791213 Pct. Reduction99.999799.999399.999099.99799.99199.98792.777 Time (days)5555555 Example98712101113 Pct. Reduction99.94799.8599.5598.9398.0492.6282.5 Time (days)7777777 Example91211108713 Pct. Reduction99.99999.99899.98999.9098.398.1581.10
Treatments listed in descending order of effectiveness for a give storage time.² Zero time data is listed in Table IV. Data for 3 and 5 days storage
at 12.8°C is listed in Table VI.
DISCUSSION OF RESULTS
For Examples 7-13, untreated inoculated controls averaged 4.8 x 10&sup7;
CFU nalidixic acid-resistant Salmonellatyphimurium
per ml of carcass
wash (Table IV). No nalidixic acid-resistant salmonellae were detected in uninoculated,
untreated controls (not listed).
Table IV lists results of enumeration of nalidixic acid-resistant
salmonellae from carcass rinse solutions for inoculated broilers subjected to
the seven test treatments at 0 days storage and at 5 and 7 days storage at 2.2°C.
Table V lists the percent reduction in numbers of nalidixic acid-resistant
Salmonellatyphimurium for each treatment in order of greatest effectiveness
at a given storage time (0, 5, or 7 days) at 2.2°C. At time 0, treatments of Examples
10, 8 and 11 were most effective immediately producing 99.9997, 99.9993, and 99.9990
percent reductions, respectively. However, at day 5 the percent reduction for the
treatments of Examples 10, 8 and 11 were 42.27, 99.366, and 35.71, respectively.
At day 7, the percentage reductions were 98.04, 90.66 and 99.9919, respectively,
for the treatments of Example 10, 8 and 11. These observations reflect recovery
of sublethally injured cells during refrigerated storage rather than outgrowth
of salmonellae during refrigerated storage at 2.2°C.
Table VI lists results of enumeration of nalidixic acid-resistant
salmonellae from carcass rinse solutions for inoculated broilers subjected to
the 7 treatments, then subsequently stored at 12.8°C for 3 or 5 days. Initial (day
0) counts are listed in Table IV. The percentage reductions from Table VII for
carcasses stored at 12.8°C are listed in Table VII together with the initial (day
0) reduction from Table IV to facilitate comparison. Note that the recovery of
injured cells observed at 2.2°C also occurs at 12.8°C. Again, no growth is evident
during the time period of this study, even at the 12.8°C storage temperature, which
reflects moderate to severe temperature abuse.
One important situation not reflected in the microbiological data
is the fact that for the sodium hydroxide treatments of Examples 10 and 11, severe
sloughing of broiler skin occurred, resulting in a very unacceptable appearance.
Both of these treatments are undesirable for commercial use.
The treatments of Examples 7 and 8, both of which involved the use
of Na&sub3;PO&sub4; . 12H&sub2;O, were essentially as effective as the treatments
of Examples 10 (sodium hydroxide) and 11, (phosphoric acid and sodium hydroxide)
without the accompanying adverse effects on appearance of the broiler carcasses.
The treatments of Examples 7 and 8 involving the use of Na&sub3;PO&sub4; . 12H&sub2;O
gave an approximately one log cycle greater kill initially that did the treatments
of Examples 9 (Na&sub2;CO&sub3;) and 12 (75% H&sub3;PO&sub4;)/Na&sub2;CO&sub3;,
both of which involved the use of Na&sub2;CO&sub3;. However, the percent reduction
for the treatment of Example 9 (Na&sub2;CO&sub3;) increased with storage at 2.2°C,
so that it had the greatest percent reduction after 5 and 7 days storage at 2.2°C,
of any of the 7 treatments (Table V). These trends were essentially the same for
the studies conducted at 12.8°C.
Two grade A broilers at a time were removed from a processing plant
after an inside and outside spray body wash just prior to the chill tanks. These
are referred to as prechill birds. The birds' temperature ranged from about 35°C
to 40°C. The birds were placed in a room temperature treatment solution which
was prepared that morning in the concentrations of trisodium orthophosphate indicated
in the example. The birds were removed from the processing line using sterile
gloves, and placed in the treatment solution for the treatment time indicated.
Another person then removed the birds from the treatment solution and put the birds
in a sterile plastic bag ready for assay and containing 200 ml of sterile buffer.
The bag was closed and shaken for one minute following standard procedure to thoroughly
contact the buffer and bird. The buffer was directed to the bottom of the bag.
The outside of the bag was sterilized, a bottom corner of the bag cut and the
buffer drained into a sterile bottle. The buffer was neutralized to pH 7' using
hydrochloric acid and the samples sent to USDA laboratory for standard analysis.
Birds were treated with 6%, 9% and 12% trisodium orthophosphate for dip times
of 5 seconds, 10 seconds and 15 seconds and were sprayed inside and out for 3 seconds
and 10 seconds. In spraying, the inside was sprayed for 1 second and the outside
for 2 seconds or the inside was sprayed for 3 seconds and the outside for 7 seconds
using a hand sprayer.
Two birds at a time were also removed on just exiting the chill tank
at a temperature of 0°-10°C and similarly treated with trisodium orthophosphate
and treated for analysis in a similar way. These birds are referred to as post
Analysis of the birds was done the first day of treatment and six
days later. Two birds were treated and tested at each treatment dip or spray time
at 0 days and six days giving a total of four birds for each dip or spray time.
Two or three days data is available for a total of eight birds used each day for
each dip or spray test condition. The raw results are given in the following tables,
where test 14 is 6%, test 15 is 9%, test 16 is 12%
trisodium phosphate, all for post chill treatment; test 17 is 6%, test 18 is 9%
and test 19 is 12% trisodium orthophosphate all for pre-chill treatment and test
20 and 21 are post-chill treatment by spray with 12% solution of trisodium orthophosphate
and example 22 is pre-chill spray treatment with 12% trisodium orthophosphate.
Examples A and B of tables VIII and IX are treatments with two days
sampling for total plate count, examples C and D of tables X and XI are two days
sampling for Enterobacteriacae. Examples E and F of tables XII and XIII are two
days sampling for E. coli and examples G and H of tables XIV and XV are two days
sampling for Salmonella.
Control data is included at the bottom of the tables. In any one
days test. poultry from about six houses was sampled and treated perhaps accounting
for the wide variation in some data.
The pre-chill results of the total plate count tests are inconclusive
but the post chill treatment with trisodium orthophosphate did reduce the plate
count compared to control. Spray results would indicate reduction in plate count
due to treatment.
The results are inconclusive.
The pre-chill and post-chill treatment, dip or spray, with trisodium
orthophosphate is effective in reducing the count of Enterobacteriacae with the
spray results very positive.
The data appears to confirm the reduction in bacteria found in Table
X, especially post-chill treatment.
The pre-chill and post-chill treatment, dip or spray, with trisodium
orthophosphate is effective in reducing the count of E. coli, particularly at higher
trisodium orthophosphate concentration.
Tables XIV and XV
The treatment with trisodium orthophosphate results in only one incident
of salmonella presence in post-chill treatment.
Trialkali metal phosphate solution at 4% or greater is also effective
against campylobacter type organisms such as C. jejuni and the like.
Further tests were conducted on whole uninoculated broiler carcasses
without giblets removed right after the chilling step in a poultry process. The
birds were obtained from a local poultry processor on the day of slaughter. Three
hundred carcasses packed on ice and held in a cooler (40°) on ice until used in
the study. The birds were taken randomly from the boxes for each of the tests.
Sterile solutions of varying concentrations of trisodium orthophosphate
were previously prepared each day for the day's tests. A total of 60 birds were
tested per trisodium phosphate concentration for three exposure times resulting
in 20 birds tested for each TSP concentration/exposure time variable. The testing
was done over 4 separate days (over a 7 day period) with five birds per TSP/exposure
time variable studied each day;
On each day a trial was conducted, an adequate number of birds
for each test variable were randomly selected from each of the shipping cartons
being held under refrigeration. The birds were placed in the designated TSP solution
and gently agitated during the exposure time. After the specified immersion time
was completed, the birds were removed from the solution legs first and drained
for a period of 30 seconds. After the drain period each processed bird was placed
in a separate sterile plastic bag containing 200 ml of sterile Butterfield's Phosphate
Buffer and rinsed for one minute by shaking through a one foot arc. After the whole
carcass rinse procedure was completed, the rinse waters were divided into two
equal aliquots (ca. 100 ml each) in sterile whirlpak bags. One of the two rinse
waters obtained from each bird was immediately neutralized using 12N HCl prior
to adding the 10X Lactose Broth enrichment medium and held at room temperature
for 30 minutes. The second rinse water per bird was enriched with 10X Lactose
Broth immediately, held at room temperature for 30 minutes, and then neutralized
with 6N HCl. That Broth enriched wash waters were then incubated at 35°C for 24
hours prior to evaluation by the Gene Trak SystemsR
probe test for the rapid detection of Salmonella species (FDA, 1984; Rose
et al., 1991). Samples determined to be positive by the gene probe assay were
confirmed by conventional culture methodology (USDA, 1974). These assays determine
the presence (positive) or absence (negative) of salmonella DNA.
The results are summarized in tables XVI-XXIII.
The data is summarized for all four days tests where the incident
of salmonella on control birds was extremely low and unexpected. The data in tables
XVI-XXI (neutralized and unneutralized buffer) clearly shows that dipping poultry
in treatment solutions containing 8% and 12% trisodium orthophosphate reduces salmonella
incidence to zero in the 10 second and 30 second dip tests. The overall results
in Table XXII for the testing show no salmonella present on 20 birds when treated
with solutions of 8% and 12% trisodium orthophosphate for 10 and 30 second dip
times and only 1 contaminated bird for the 15 minute dip time compared to 5 contaminated
birds for control, 5 contaminated birds for 1% TSP and 4 contaminated birds for
Table XXIII summarizes the percent of positive incidence of Salmonella
found for each bird after treatment and clearly shows that treatment of broilers
during processing with at least about 4% trisodium orthophosphate reduces the
incidence of Salmonella contamination. The present experiment on uninoculated
birds is clear evidence that high concentrations of trisodium orthophosphate solution
is unexpectedly able to reduce the incidence of natural Salmonella contamination
on broilers compared to a water wash or use of low concentrations (1% or less)
trisodium phosphate. The test results of tables XXII and XXIII confirm the earlier
results set forth herein which indicate that a treatment solution containing about
4% or more trisodium orthophosphate is effective to remove, reduce or retard salmonella
and other bacteria on poultry.
Detection of salmonella positive post chill whole broiler carcasses
after exposure to various concentrations of Trisodium Phosphate (all trials) Exposure Time Trisodium Phosphate Concentration (%w/w) Neutralized Buffer Non-Neutralized Buffer Totala10 Seconds02/20b1/202/20 12/200/202/20 42/201/202/20 80/200/200/20 120/200/200/20 30 Seconds01/201/202/20 12/200/202/20 41/201/201/20 80/200/200/20 120/200/200/20 15 Minutes01/200/201/20 11/200/201/20 41/200/201/20 80/200/200/20 121/201/201/20
a - Total number of individual birds
found to be positive for Salmonella.b - Number of individual birds positive for Salmonella per
number of individual birds tested.
Percent of Salmonella positive post chill whole broiler carcasses
detected after exposure to various concentrations of Trisodium PhosphateaTrisodium Phosphate Concentration (%w/w) Percent Positive 08.3 18.3 46.7 80 121.7
a - Percent of birds found to
be positive for Salmonella for all exposure times for all trials.
Trisodium phosphate either alone or in combination with other food
ingredients seems to have great potential for use in eliminating salmonella on
Example 24Carcass Preparation
A barrow was slaughtered and split in half. The right side was used
as Control and the left side was treated with trisodium orthophosphate (TSP). One
hour and fifteen minutes post-slaughter (pre-rigor), the left side was totally
submerged in a solution (pH 13.14) containing 10% TSP for 2 minutes, then subsequently
placed in a 38°F cooler with the control for 48 hours.
Fifteen minutes following treatment, both Control and orthophosphate
carcasses were surface swabbed at two locations at a portion of the belly that
parallel to the 10th rib and an area on the carcass exterior (skin)
directly opposite the 10th rib sampling location.
The areas were swabbed (18 strokes) with a sterile bent glass rod.
The rod was then placed in 50 ml of a phosphate buffer (pH 6.0). One milliliter
of the 50 ml solution was then diluted in a 9 ml phosphate buffer (pH 6.0). A
total of 6 dilutions were performed. After dilution, 1/10 ml was placed in a petri
dish containing a pre-poured agar with 10% sheep's blood. The dishes were incubated
for 48 hours at 34°F. Total plate counts were then conducted.
A 48 hour swabbing was also conducted in the same manner as previously
mentioned but at 5 different locations. These locations were as follows:
1. Parallel the anterior end of aitch bone.
2. Diaphragm muscle located ventral to the 10th
3. Jowl region
4. Skin of the ham opposite the aitch bone.
5. Skin of the shoulder opposite the 2nd rib.
A meat sample was obtained from the anterior end of the aitch bone
(location 1) and the belly located ventral to the 10th rib (location
2). A surface pH was taken on each sample. The meat sample was then ground and
a composite pH was taken.
Table XXIV shows that the surface pH was greater than the ground
sample pH but this difference was not greater than the 1.0 pH point at any given
location. The TSP treated sample pH was greater than the control for both surface
and ground sample pH readings. However, the greatest pH difference was 0.32 between
the surface pH of the control belly and TSP belly. These findings suggest that
the little difference between the control and TSP would have no effect on processing
or consumer preference.
1.5 Hours Post-Slaughter
There was no distinct visual differences between the control and
the TSP treated carcass. The TSP treated carcass did have a slightly darker pigment
color but was not that easily recognizable.
The total plate count conducted was inconclusive for both the control
48 Hours Post-Slaughter
Visual appearance at this time period was very similar to the 1.5
hour post-slaughter, showing little difference in muscle pigment color between
the control and TSP.
The Total Plate Count (Table XXV) showed bacterial growth in the
nondiluted control sample but not the TSP treated sample. The greatest plate count
was found at the aitch bone followed by the belly, jowl, shoulder (skin) and ham
(skin). There was no growth recorded in the dilutions for either the control or
The Example shows a surprising lack of discoloration of a paired
split hog carcass treated pre-rigor with trisodium orthophosphate.
The Example clearly shows the ability of Trisodium Phosphate to control
bacterial contamination and/or growth on a hog carcass without affecting the visual
appearance of the lean muscle. A 10% trisodium orthophosphate solution was used
to submerge the hog carcass for a two minute time treatment gave a complete reduction
of total plate count based on 48 hour swabbing done at various locations on the
carcass.Trisodium phosphate either alone or in combination with other additives,
with the proviso that the treatment solution of orthophosphate is free of alcohol,
nitrite or nitrates, and ascorbic acid has great potential for use in eliminating
salmonella and other organisms red meat carcasses.
Tests were made to determine the antimicrobial effectiveness of trisodium
orthophosphate (TSP) on the survival of several typical seafood spoilage bacterial
in laboratory model systems.
A. Test Variables
Two different test systems (i.e. water systems) were used to evaluate the efficacy
of two different chemical additives which were labeled "Agent A" (3% TSP) and
"Agent B" (1.5% TSP + 1.5% KCl). One water system was formulated as a sterile synthetic
sea water according to the following formula.
Chemical Percent NaCl2.348 MgCl&sub2; s 6H&sub2;o1.065 Na&sub2;SO&sub4;0.392 CaCl&sub2; x 2HO0.146 KCl0.066 H&sub2;O95.98 Total100.00
The second water system was comprised of sterile deionized water,
and represents fresh water. The concentration of Agent A and Agent B that was added
to separate sea water systems for evaluation was 0.5% (w/v). The concentration
of Agents A and B that were added to separate fresh water systems was 3.0% (w/v).
B. Test Microorganisms
For the purpose of this evaluation, three commonly identified seafood spoilage
microorganisms were utilized. They included:
The antimicrobial efficacy of each chemical additive in each water system was evaluated
against 24 hour cultures of the first two strains, and 48 hour cultures were evaluated
for the slower growing Moraxella species.
C. Test Procedure
Ninety nine ml volumes of the test water systems with the appropriate concentrations
of Agents A or B in 250 ml Erlenmeyer flasks were tempered to a constant temperature
of 27°C. in a water bath. Each flask was inoculated individually with one ml of
the test culture. Target inoculum level was 1.0 x 10&sup8; cfu/ml. to yield a
flask inoculum level of 1.0 x 10&sup6;cfu/ml. The flasks were agitated and a 1
ml time zero sample was removed into a 9 ml neutralization blank. After 60 seconds
of contact time another 1 ml sample was removed into a second 9 ml neutralization
blank. Samples were plated in triplicate using serial dilutions. The spread plate
method was used for P aeruginosa and pour plate method was used for the
other two test strains. Each trial was run in duplicate, and a time zero culture
control was included for each trial.
RESULTS AND DISCUSSION
The results of experiments evaluating the effect of Agents A and
B against P aeruginosa at 27°C are presented in Tables 26 and 27. The percent
reductions of the bacterial populations after treatment with these Agents are
presented in Tables 28 and 29.
Recovery of P. aeruginosa after Treatment with Agent A in Fresh (3.0%)
and Synthetic Sea Water (0.5%) Systems. Initial Inoculum REPLICATE A B Fresh WaterT=06.8 x 108a<1.0 x 103a<1.0 x 10³ T=60<1.0 x 10³<1.0 x 10³ Sea WaterT=05.1 x 10&sup8;3.9 x 10&sup8;5.5 x 10&sup8; 1.1 x 10&sup8;9.2 x 10&sup7;
Percent Reduction of P. aeruginosa after Treatment with Agent A in
Fresh (3.0%) and Synthetic Sea Water (0.5%) Systems. Initial Inoculum REPLICATE Average A B Fresh WaterT=06.8 x 108a>99.994b>99.994>99.994 T=60>99.994>99.994>99.994 Sea WaterT=05.1 x 10&sup8;42.619.130.9 T=6083.886.585.2
a cfu/m.b %
Recovery of P. aeruginosa after Treatment with Agent B in Fresh (3.0%)
and Synthetic Sea Water (0.5%) Systems. Initial Inoculum REPLICATE A B Fresh WaterT=06.0 x 108a<1.0 x 103a<1.0 x 10³ T=60<1.0 x 10³<1.0 x 10³ Sea WaterT=04.5 x 10&sup8;3.0 x 10&sup8;4.2 x 10&sup8; T=603.4 x 10&sup8;3.6 x 10&sup8;
Percent Reduction of P. aeruginosa
after Treatment with Agent B in
Fresh (3.0%) and Synthetic Sea Water (0.5%) Systems. Initial Inoculum REPLICATE Average A B Fresh WaterT=06.0 x 108a>99.994b>99.994>99.994 T=60>99.994>99.994>99.994 Sea WaterT=04.5 x 10&sup8;33.324.428.9 T=607.120.013.6
Both Agent A and Agent B were effective at the 3.0% level in the
fresh water systems, showing a > 99.994% reduction for both T=0 and T=60 seconds.
At the 0.5% level in sea water, Agent A was minimally effective, showing an average
reduction of 30.9% at T=0. Agent A was more effective at T=60 seconds (avg. reduction
85.2%). Agent B was even less effective in sea water showing an average initial
reduction of 28.9% and an average reduction of only 13.6% after 60 seconds contact
The effects of Agents A and B on B. cereus are presented in
Tables 30 and 32. Tables 31 and 33 show the percent reduction of B. cereus
in these lab model systems.
Recovery of B. cereus after Treatment with agent A in Fresh (3.0%)
and Synthetic Sea Water (0.5%) Systems. Initial Inoculum REPLICATE A B Fresh WaterT=04.0 x 107a1.6 x 105a6.6 x 10&sup4; 5.9 x 10&sup4;3.3 x 10&sup4; Sea WaterT=604.0 x 10&sup7;3.2 x 10&sup7;3.3 x 10&sup7; 2.9 x 10&sup7;3.1 x 10&sup7;
Percent Reduction of B. cereus after Treatment with Agent A in Fresh
(3.0%) and Synthetic Sea Water (0.5%) Systems. Initial Inoculum REPLICATE Average A B Fresh WaterT=04.0 x 107a99.6b99.899.7 T=6099.999.999.9 Sea WaterT=04.0 x 10&sup7;20.017.518.8 T=6027.522.525.0
Recovery of B. cereus after Treatment with Agent B in Fresh (3.0%)
and Synthetic Sea Water (0.5%) Systems. Initial Inoculum REPLICATE A B Fresh WaterT=03.4 x 107a1.3 x 104a1.8 x 10&sup4; T=609.0 x 10³1.0 x 10&sup4; Sea WaterT=03.4 x 10&sup7;2.8 x 10&sup7;3.0 x 10&sup7; T=602.5 x 10&sup7;2.6 x 10&sup7;
Percent Reduction of B. cereus after Treatment with Agent B in Fresh
(3.0%) and Synthetic Sea Water (0.5%) Systems. Initial Inoculum REPLICATE Average A B Fresh WaterT=03.4 x 107a99.96b99.9599.96 T=6099.9799.9799.97 Sea WaterT=03.4 x 10&sup7;17.711.814.8 T=6026.523.525.0
In the fresh water system (3.0%) Agents A and B both gave a high
percentage of reduction at T=0 (99.7 and 99.96 respectively). The reduction at
T=60 was 99.9% for Agent A and 99.97% for Agent B for this system. Both were much
less effective in the sea water systems (0.5%) showing less than 30% reduction
at both times for both Agents.
The results of experiments evaluating the effectiveness of Agent
A and Agent B against M. osloensis
at 27°C. are shown in Tables 34 and 36.
The percent reduction of bacterial populations after contact with Agents A and
B are shown in Tables 35 and 37.
Recovery of M. osloensis after Treatment with Agent A in Fresh (3.0%)
and Synthetic Sea Water (0.5%) Systems. Initial Inoculum RELATIVE A B Fresh WaterT=01.7 x 107a9.2 x 106a1.1 x 10&sup7; T=601.9 x 10³1.0 x 10³ Sea WaterT=01.7 x 10&sup7;1.2 x 10&sup7;1.3 x 10&sup7; T=601.3 x 10&sup7;1.3 x 10&sup7;
Percent Reduction of M. osloensis after Treatment with Agent A in
Fresh (3.0%) and Synthetic Sea Water (0.5%) Systems. Initial Inoculum RELATIVE Average A B Fresh WaterT=01.7 x 107a45.9b35.340.6 T=6099.99499.99499.994 Sea WaterT-01.7 x 10&sup7;29.423.526.5 T=6023.523.523.5
a cfu/mlb %
Recovery of M. osloensis after Treatment with Agent B in Fresh (3.0%)
and Synthetic Sea Water (0.5%) Systems Initial Inoculum RELATIVE A B Fresh WaterT=09.9 x 106a4.2 x 106a4.9 x 10&sup6; T=60<1.0 x 10³2.0 x 10³ Sea WaterT=09.8 x 10&sup6;7.0 x 10&sup6;7.7 x 10&sup6; T=606.9 x 10&sup6;6.6 x 10&sup6;
Percent Reduction of M. osloensis after Treatment with Agent B in
Fresh (3.0%) and Synthetic Sea Water (0.5%) Systems Initial Inoculum REPLICATE Average A B Fresh WaterT=09.8 x 106a57.1b50.053.6 T=60>99.9499.98Sea WaterT=09.8 x 10&sup6;28.621.425.0 T=6029.632.731.2
a cfu/mlb %
The initial reduction was only approximately 50% for both agents
at the 3.0% level in the fresh water system. After sixty seconds the percent reduction
was >99.98 for both agents. Initially, Agent B showed a slightly greater reduction
than Agent A. In the sea water systems these agents were unable to produce a reduction
of more than 30%.
Overall, both Agents A and B at the 3.0% level in fresh water caused
a reduction of >99.6% for all bacteria tested after sixty seconds contact time.
Both agents at this level caused >99.6% reduction initially for P. aeruginosa
and B. cereus. The Moraxella strain used was less effected by these
Agents at T=0.
The systems with 0.5% agent added to synthetic sea water produced
a reduction of less than 31% in all but the T=60 trial against P. aeruginosa.
Trisodium orthophosphate either per se or in combination with other
ingredients seems to have great potential for use in eliminating spoilage bacteria
during processed raw fish and crustaceans. For naturally occuring microorganisms
about 4% to saturation of trisodium orthophosphate is effective.
A process for treating edible animal carcasses comprising treating the surface
of animal carcass with an aqueous treatment solution having a pH above about 11.5,
said solution containing trialkali metal orthophosphate present in an amount effective
to remove, reduce or retard bacterial contamination and/or growth.
The process of Claim 1 wherein the amount of orthophosphate is about 4% or
greater based on the weight of the solution with the proviso that the orthophosphate
solution does not contain alcohol.
The process as recited in Claim 1 or 2 wherein said animal is poultry, fish
or red meat and said orthophosphate is trisodium orthophosphate and the bacterial
contamination includes salmonella.
The process as recited in any of Claims 1 to 3 wherein said pH ranges from
about 11.6 to about 13.5.
The process as recited in any of Claims 1 to 4 wherein residual phosphate is
left on the animal to provide reduced bacterial activity on the surface of the
The process as recited in Claim 4 wherein said animal is poultry and is treated
at a temperature of 0°C to 70°C by a dip or spray of the solution for a period
of several seconds to several hours.
The process as recited in Claim 6 wherein said poultry is treated at a temperature
of 20°C to 70°C.
The process as recited in Claim 6 wherein said poultry is treated at a temperature
equal to or less than 27°C.
The process as recited in Claim 6 wherein said poultry is treated for less
than 30 seconds at a temperature equal to or less than 10°C.
The process of any of Claims 1 to 5 wherein said animal is fish and crustaceans
and wherein the amount of orthophosphate is about 4% or greater based on the weight
of the solution with the proviso that the treatment solution does not contain alcohol,
ascorbic acid or phosphates other than orthophosphate and phosphates naturally
present in the water used to make the treatment solution.
The process as recited in Claim 10 wherein the time of treatment is up to 30
The process of Claim 11 in which seafood spoilage bacteria, Pseudomonas aeruginosa,
Bacillus Cereus, Moraxella osbersis are retarded, reduced or removed by treatment
with 4% to saturation of a trisodium phosphate solution having a pH exceeding 12.0
The process of any of Claims 1 to 5 wherein said animal is a red meat animal
and wherein the amount of orthophosphate is about 4% or greater based on the weight
of the solution and the treatment is effective to retard, reduce or remove bacterial
contamination and/or growth without substantial color change caused by the treatment
solution pH and with the proviso that the solution does not contain alcohol, nitrate
or nitrite, or ascorbic acid.
The process as recited in Claim 13 wherein said orthophosphate is trisodium
orthophosphate and the amount of orthophosphate is about 4% to saturation.
The process as recited in any of the preceding claims in which the treatment
solution pH ranges from 11.6 to about 13.5 and the solution is applied pre-rigor.
The process as recited in Claim 13 wherein treatment is conducted below 10°C
and is followed by conventional processing of the red meat.
The process of Claim 13 in which salmonella, campylobacter, listeria and spoilage
bacteria are retarded, reduced or removed by treatment with 4% to saturation of
trisodium phosphate solution having a pH exceeding 12.0.
Surface-treated edible animal carcasses characterized in that the same have
undergone treatment according to any of Claims 1 to 17.