Establishment of critical hygiene indices for meat cooling processes evaluated by a temperature function integration...

Area of Science:

• Food Safety
• Microbiology
• Meat Science

Background:

• The New Zealand industry standard for meat cooling uses the process hygiene index (PHI) to assess potential enteric bacteria growth.
• Current PHI criteria lack flexibility by not accounting for differences between meat products.
• This limits adaptability in meat processing operations.

Purpose of the Study:

• To develop a new methodology for setting meat processing acceptability criteria based on initial Escherichia coli levels.
• To establish flexible PHI criteria that account for meat product variations.
• To ensure good-practice meat processing operations meet updated hygiene standards.

Main Methods:

• Developed a methodology using the frequency distribution of initial Escherichia coli (E. coli) on carcasses (log2 CFU/cm²).
• Incorporated a requirement for E. coli numbers to be below a maximum acceptable level post-cooling.
• Utilized Monte Carlo modeling to assess the implications of new PHI criteria on beef and lamb cooling processes.

Main Results:

• Proposed PHI criteria were developed using industry-wide initial E. coli data and accepted E. coli guidelines.
• Monte Carlo simulations showed that proposed criteria could allow higher PHI for beef than lamb cooling.
• Differences in allowable PHI are attributed to lower initial E. coli counts typically found on beef carcasses.

Conclusions:

• The new methodology provides more flexible and product-specific criteria for evaluating meat cooling processes.
• Adoption of these criteria can enhance processing flexibility while maintaining high hygiene standards.
• The findings support differentiated PHI criteria for different meat types, such as beef and lamb.