Background of the Invention

1 Field of the Invention

The present invention relates to an improved process for reducing the level of and retarding the growth of bacteria, on newly slaughtered raw red meat carcasses, poultry carcasses or seafood without causing organoleptic depreciation thereof The process selected is the combination of steam and a tπalkali metal orthophosphate solution

2 Technology Description

The applicants' assignee has obtained a number of United States patents directed to the use of aqueous solutions of tπalkali metal orthophosphate, preferably tπsodium orthophosphate, to treat red meat poultry and seafood These include the following 5,069.022, 5,143,739, 5,192.570 5.262.186, 5,268.185, 5,283 073. and 5.354,568 Each of these patents is characterized by including a treatment step wherein at least a four percent aqueous solution of tnalkali metal orthophosphate is used

The combination of hot water with phosphates as a way to reduce bacterial contamination of poultry has been reported in Thomson et al "Phosphate and Heat Treatments to Control Salmonella and Reduce Spoilage and Rancidity on Broiler Carcasses", Poultry Science 58:139-143 (1979) The phosphates used in the evaluation are sodium tripolyphosphate and sodium hexametaphosphate

CONFIRMATION COPT

The use of hot scald water having a pH of about 9 to reduce contamination of poultry has been reported in Humphrey et al., "The Effect of pH Adjustment on the Microbiology of Chicken Scald-tank Water with Particular Reference to the Death Rate of Salmonellas", Journal of Applied Bacteriology, 51 :517-527 (1981 ). The basic chemicals used to adjust samples of the scalding water to a pH of about 8.8 were sodium and potassium hydroxide, sodium carbonates and tπ-sodium phosphate

Different methods for the pasteurization of poultry meat are discussed in Teotia. "Chemical Pasteurization of Poultry Meat", Ph.D. Thesis, Colorado State University, 1973. Various treatments are described in the thesis including the testing of sodium carbonate, sodium borate or potassium hydroxide solutions at elevated temperatures and testing involving the use of only hot water

It would be desirable to achieve effective bacterial reduction while potentially reducing the amount of triaikali metal orthophosphate used and by using a treatment means in addition to the triaikali metal orthophosphate treatment In accordance with this invention it is possible to achieve this result by utilizing the combination of steam with a triaikali metal orthophosphate solution

Summary of the Present Invention

In accordance with the present invention, there is provided a process for treating red meat carcasses (including parts and organs), poultry carcasses (including parts and organs) and seafood to remove, reduce or retard bacterial growth, such as salmonella, campylobacter, E. coli, and spoilage bacteria, without significantly affecting the organoleptic properties of the carcass. The process comprises surface treating the red meat carcasses, poultry carcasses or seafood with a combination of steam and triaikali orthophosphate, preferably above pH 11.5, without significantly changing the color of the surface being treated resulting from high pH or the steam treatment.

The use of the term 'carcass as used in this application expressly includes the above defined external and internal parts and organs of the red meat, poultry or seafood.

More particularly, the treatment comprises the application, preferably simultaneous, of steam and the tπalkali metal orthophosphate solution The concentration of triaikali metal orthophosphate in the solution ranges from about 0 1 percent to saturation In preferred embodiments, the temperature of the steam is about 100°C to about 116°C and at a pressure of about 0 psig to about 10 psig All pressure and temperature measurements are at sea level Alternatively, the steam and treatment solution steps may be applied sequentially

The process is preferably conducted by spraying the steam and orthophosphate solution onto all surfaces of the carcass for one second to 8 seconds In the case of red meat, preferably treatment is done before rigor on set In the case of poultry, treatment is preferably done before chilling

Specifically, it has been discovered that carcasses can be treated with steam and from about 0 1 % to saturation of a aqueous solution of tπsodium or tπpotassium orthophosphate dodecahydrate or an equivalent amount of the anhydrous compound

By use of this process the carcasses can be treated economically and simply with a food grade product to achieve salmonella and other bacteria control without organoleptic depreciation of the carcass and organs and can take advantage of the sterilizing effect that the steam treatment may afford

An object of the present invention is to provide a method for reducing bactena on red meat, seafood and poultry carcasses

Still another object of the present invention is to provide a method for reducing bactena on red meat, seafood and poultry carcasses which utilizes minimal amounts of treatment solutions

A further object of the present invention is to provide a method for reducing bacteria on red meat, seafood and poultry carcasses which utilizes the combined effects from a treatment solution and steam

These, and other objects, will readily be apparent to those skilled in the art as reference is made to the detailed description of the preferred embodiment

Detailed Description of the Preferred Embodiment

In describing the preferred erriDodimeπt certain terminology will be utilized for the sake of clarity Such terminology is intended to encompass the recited embodiment as well as all technical equivalents which operate in a similar manner for a similar purpose to achieve a similar result

The present invention involves using two types of treatment to reduce bacterial contamination of an animal carcass The two types of treatment are (1 ) treatment with a triaikali metal orthophosphate solution and (2) treatment with steam

The invention is applicable to any red meat including pork beef veal mutton lamb and goat, either whole carcass or fresh parts including internal organs such as hearts kidneys and livers, preferably before rigor This invention is further applicable to any poultry carcass or fresh parts, including internal organs such as hearts kidneys and livers, including but not limited to chicken, turkey, hen squab, duck quail and the like or any type of seafood including but not limited to shellfish fresh water fish and sea (salt) water fish in either whole, eviscerated or filleted condition

The carcass surface and/or organs is treated with a triaikali metal orthophosphate solution and steam either before during or after chilling Application of the steam and tralkali metal orthophosphate may occur sequentially or simultaneously with a simultaneous application being particularly preferred

The first type of treatment is the use of a triaikali metal orthophosphate aqueous solution Triaikali metal phosphate is an orthopnosphate salt of the formula R ₃ P0 ₄ with a formula for the sodium salt being Na ₃ P0 ₄ and an equivalent formula for the tπpotassium compounds R is an alkali metal of sodium or potassium Tπsodium phosphate has a minimum of 41 5% P ₂ 0 ₅ and a typical pH in a 1 % solution of about 1 1 8

Tπsodium phosphate is available as the dodecahydrate and in commerce the dodecahydrate is available in technical or food grade Preferably the dodecahydrate (either form) is used As used herein tπsodium phosphate is intended to include tπpotassium phosphate as well as all forms of those compounds

The carcass is treated with a solution containing from about 0 10% to saturation preferably from about 5% and more preferably from about 1 % to saturation of triaikali metal orthophosphate by weight From about 25% to 20% preferably 0 5-15% and most preferably from about 1 0% to 12% (including 1 2 4 6 8 10 and 12 percent solutions) of triaikali metal orthophosphate can be effective

The treatment solution may also include a minor amount of other alkaline materials such as carbonates and hydroxides Specific examples include sodium hydroxide potassium hydroxide sodium carbonate potassium carbonate sodium tripolyphosphate and mixtures thereof The term a minor amount defines less than 50% by weight of the combined dry weight of the triaikali metal orthophosphate and the alkaline material usually and in all cases in an amount insufficient to cause organoleptic deterioration

The carcass can be dipped in the treatment solution preferably with solution agitation to increase contact of the treatment solution with all surfaces and crevices of the carcass including the internal organs The treatment solution is preferably applied by mechanical sprayers usually under high pressure to insure good contact of the treatment solution with the surface The treatment solution preferably contains only triaikali 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 orthophosphate

In the case of treating poultry carcasses it is preferred to employ the triaikali orthophosphate treatment immediately after the scalding treatment either before or after defeatheπng 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

In the case of treating red meat it is preferably treated with the triaikali metal orthophosphate either before or directly after skinning and usually prior to chilling In particularly preferred embodiments the treatment is performed pre rigor

In the case of seafood the treatment with the triaikali metal orthophosphate can occur 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 seafood is treated either just after catch on the fishing boat or shortly after arrival at the processing plant prior to cooKing or packaging it is particularly preferred to use the treatment solution after evisceration and during washing or after washing the flesh

The treatment solution preferably comprised of triaikali metal orthophosphate is in an amount sufficient to provide a pH above about 1 1 5 and preferably within a range from 1 1 6 to 13 5 and most preferably from about pH 12 to pH 13 5

At atmospheric pressure in a dip tank dwell times from 5 seconds to about 30 mir jtes are effective while dwell times using a spray range from several seconds to several π - utes or 2 seconds to 15 minutes with spray times of less than 30 seconds preferred

The high pH of over 11.5, preferably about pH 12 or above is critical to remove, reduce or retard bacterial contamination or growth The mechanism is not entirely understood, but the orthophosphate appears to improve bacterial removal as well as retarding growth of any residual bacteria

The second treatment step compπses the use of steam More particularly, the carcass to be treated is contacted with steam at a temperature of about 100°C to about 116°C, more preferably at a temperature of about 100°C to about 110°C, most preferably at a temperature of about 107°C to about 1 10°C, and at a pressure of about 0 psig to about 10 psig, more preferably at a pressure of about 0 psig to about 5 psig, most preferably at a pressure of about 0 psig to about 1 psig All pressure and temperature measurements are at sea level

The time for treatment typically ranges from about 1 sec to about 20 sec , more preferably from about 1 sec to about 8 sec and most preferably from about 1 sec to about 3 sec

When the steam treatment is simultaneous with the tralkali metal orthophosphate treatment, the treatment time would be the same for both types of treatment A particular concern is that the treatment time be short enough so that the organoleptic properties of the treated surface are not significantly modified

When the treatment steps occur sequentially, the steam application step may either precede or follow the tralkali metal orthophosphate treatment step

In a particularly preferred embodiment, the treatment solution is aspirated or injected directly into the steam

As would be readily understood by one skilled in the art. the treatment time solution concentration and temperature are selected such that the organoleptic properties of the animal or seafood being treated do not appreciably change For example, when treating beef samples slight discoloring may occur, but not enough to effect the overall taste appearance and the like.

We have found the triaikali metal orthopnosphate treatment solution is effective against salmonella, campylobacter. E coli. pseudomonas. bacillus, moraxella. spoilage bacteria and the like.

It is also hypothesized by the in entors that the combination of steam and a triaikali metal orthophosphate solution may increase the shelf-life of the resulting poultry, red meat or seafood. Increases of about one to about fourteen days may be achieved by utilizing the inventive method.

The invention is further descrioed in the following non-limiting Example

Example

The combination of steam and tπsodium orthophosphate (dodecahydrate) is used to determine the efficacy against E coli 0157 h7 under several operating conditions The samples used to test efficacy are beef goose neck rounds purchased from a grocery store which are then inoculated with E coli 0157 7 strains (both clinical isolates and beef isolates) at about 70°F The inoculated beef rounds are then subjected to the simultaneous combination of steam (102°C 4 r 2 psi j or high pressure air (ambient. 50 psi or 14 psi ) with a treatment solution ideionized water or a 12% aqueous solution of tπsodium orthophosphate) Testing is done using a Fisner Scientific Fisher Airejector Aspirators ^'' (found on page 865 Fisher Catalog 95/96) Three aspirators are arranged so that they can contact one target area. A specially designed target box is designed to hold the aspirators and meat target and shutters are designed to control the target time of exposure.

The different combinations that are used are

Sample A: Steam and 100% αeionized water

Sample B Steam and 12% tπsodium orthophosphate (TSP) solution (resulting in a flow rate of TSP solution of 8.3 ml/s)

Sample C 50 psig air and 12% tπsodium orthophosphate (TSP) solution (resulting in a flow rate of TSP solution of 5.0 ml/s)

Sample D 14 psig air and 12% tπsodium orthophosphate (TSP) solution (resulting in a flow rate of TSP solution of 1 7 mi/s)

Sample E No treatment (control)

To test the efficacy of the various treatments, surfaces of meat that have been inoculated are mounted vertically on hooks and placed in a box where the nozzles of the apparatus used for the different sample treatments are located 8 inches from the inoculated area. Samples are exposed to the different treatments for a time period of 15 seconds Triplicate experiments are conducted After treatment, the inoculated areas are excised and tested for remaining bacteria The results are shown in the attached table and are reported as the number of microorganisms per square centimeter The amount of microorganism remaining in log units is shown in parenthesis

SAMPLE EDPERDIENT 1 EXPERIMENT 2 EXPERIMENT 3 AVERAGE

A 9.2 x 10 ¹ 8 4 x 10° 9.2 x 10° 3.7 x 10 ¹

(1.96) (0.92) (0.96) d -57)

B <1 2 x 10 ^υ 3.7 x 10' <1.2 x 10 ^u <1.3 x 10' (0.08) (1.57) (0.08) (<1.11 )

C 4 4 x 10 ^J 1 8 x 10 ^J 9.6 x 10' 2.5 x 10 ^J (3.63) (3.26) (2.98) (3.38)

D >4 4 x 10 ^J >4 4 x 10 ^J 4 4 x 10 ^J >4.4 10° (3.64) (3.64) (3.64) (3.64)

E >4 4 x 10" >4 4 x 10" >4.4 x 10" >4 4 x 10" (4.64) (4 64) (4.64) (4.64)

The above experiment is repeated using the following treatment methods with the only difference being the reduction of the treatment time to 8 seconds.

Sample F Steam (approx. 14 psig)

Sample G: Steam (approx. 14 psig) and 12% trisodium orthophosphate (TSP) solution (resulting in a flow rate of TSP solution of 10.0 ml/s).

Sample H: No treatment (control)

The above data demonstrates that the combination of steam and triaikali metal orthophosphate is effective to significantly reduce bacterial contamination. More specifically, while both the use of steam and trisodium orthophosphate. alone, will function to reduce the remaining bacteria on the surface, the combined effects of the two treatments yield results which approach multiple (i.e., greater than 3) log reductions, thereby reducing the final bacterial contamination by at least 99 percent, and typically by at least 99.9 percent. This affords the food processor with the opportunity to provide an extremely safe product to the ultimate consumer.

Having descπbed the invention in detail and by reference to the preferred embodiments thereof it will be apparent that modifications and vaπatioπs are possible without departing from the scope of the appended claims