Evaluation of Alternative Cooking and Cooling Procedures for Large, Intact Meat Products to Achieve Lethality and Stabilization Microbiological Performance Standards

摘要

This study was conducted to determine if alternative heating times and slowercooling times, other than those defined by FSIS, could be utilized and still comply withFSIS performance standards. Large (10.43 to 12.25 kg), cured bone-in hams (n = 190)and large (greater than or equal to 9.07 kg), uncured beef inside rounds (n = 180) were utilized in a two-phasestudy. Phase 1 of the study investigated the effect of alternative lethality parameters ontoxin production of Staphylococcus aureus and log reduction of SalmonellaTyphimurium and coliforms. Both the hams and roast beef were subjected to 1 of 10treatments defined by varying final internal product temperatures (48.9 degrees C, 54.4 degrees C,60.0 degrees C, 65.6 degrees C, or 71.1 degrees C) and smokehouse relative humidities (50% or 90%). Phase 2investigated the effect of alternative stabilization parameters on log growth ofClostridium perfringens. Stabilization treatments extended the times taken to reduceinternal product temperature from 54.4 degrees C to 26.7 degrees C and from 26.7 degrees C to 7.2 degrees C (ham) or4.5 degrees C (beef), independently. Further, a control treatment following current FSIS,Appendix B guidelines was conducted for ham, and a "worst case" scenario wasassessed for both products. The "worst case" treatment evaluated the effects of cooling products at room temperature (approximately 22.8 degrees C) in place of normal coolingprocedures in a temperature controlled environment. Results of the study showed atleast a 6.5-log10 reduction in S. Typhimurium across all lethality treatments for bothproducts. Further, coliform counts also were reduced significantly, and S. aureus toxinkits returned negative results for toxin production for all treatments of ham and roastbeef. Stabilization showed less than 1-log growth of C. perfringens for any treatment,with the exception of the "worst case" scenario for roast beef. As expected, > 1 loggrowth of C. perfringens was found for uncured roast beef maintained at roomtemperature for cooling. This study supports that there are multiple time andtemperature combinations, other than those currently provided by FSIS, which may beutilized for cooking and cooling large roast beef and bone-in ham products while stillmeeting FSIS lethality and stabilization microbiological performance standards.