Investigating the Development of Thermal Processing Tools to Improve the Safety of Ready-To-Eat Meat and Poultry Products

This study will investigate the impact of compositional, physical, and intrinsic factors on pathogen lethality and the relationship between relative humidity and wet bulb control to determine if wet bulb could be utilized as a more effective and suitable lethality tool. This project builds on previous AMIF-funded research.

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Objectives

• Investigate the effect that certain thermal processing parameters and product characteristics have on the thermal inactivation of pathogenic Salmonella and L. monocytogenes;
• Develop scientifically based, regulatory supported, and industry useful thermal processing parameters to assure pathogen destruction and regulatory compliance in pre-cooked meats considering the vast array of products and thermal processing methods.

Conclusions

This study investigated the validity of thermal processes designed to meet USDA, FSIS Appendix A lethality requirements for four different ready-to-eat, small dimension, fast-cook products (frankfurters, beef patties, chicken patties, chicken tenders). Results from this study confirmed that cooking temperatures and times that are currently being widely used in the meat and poultry industries following USDA, FSIS Appendix A for thermal lethality are sufficient to kill 1) Salmonella when the end point cooking temperatures meet or exceed 60.0°C (140°F) for non-impingement processes and 2) L. monocytogenes when the end point cooking temperatures meet or exceed 71.1°C (160°F) for non-impingement processes. Additionally, wet-bulb time/temperature target identified in this study (DB = 79.4°C (175°F, WB = 65.6°C (150°F), 15 minutes) may be a suitable replacement for Appendix A relative humidity requirements during smokehouse processing.

In contrast, Salmonella was found to be more thermotolerant than L. monocytogenes during rapid cook impingement processes (≤4.0 minutes). As product size and cook times decreased, a surface lethality step (SLS) was necessary to counter the protective effects of dehydration for pathogens — especially Salmonella — on the product surface. The protective effect of dehydration at the product surface was more pronounced for Salmonella than for L. monocytogenes, and therefore higher wet-bulb temperatures or SLS steps with longer dwell times may be necessary to assure 5-log kills of Salmonella. Understanding and instituting integrated lethality concepts are critical to ensuring the safety and efficacy of the lethality steps during these processes. The integrated process lethality profiles developed from this study will be useful tools for establishments to better evaluate overall pathogen lethality of their products and processes. Finally, the results of this study have also enabled the on-going development of new easy-to-use time-temperature tables for frankfurters, beef patties, chicken patties, and chicken tenders for validated reductions of both pathogens investigated.

Deliverable

Because of the wide variety of processed meat products, thermal process validations that encompass this wide range of products are important to confirm pathogen destruction during cooking. The results of this study will contribute to the on-going development of new easy-to-use time-temperature tables for frankfurters, beef patties, chicken patties, and chicken tenders for validated reduction of the pathogens investigated.