Additional thermal processing can reduce, eliminate surface pathogens.

In the past two decades, much has been learned about L. monocytogenes as a foodborne pathogen. We've learned about its many virulence factors, how it may be transferred from product to product and its sources of contamination. Researchers have developed diagnostic techniques for its detection and differentiation.

Still, the bacteria have remained a common and significant pathogen, contaminating environmental surfaces in facilities that produce ready-to-eat (RTE) meat and poultry products, despite the implementation of HACCP controls. The USDA-FSIS has responded to the challenge by providing greater incentives for reducing pathogens if companies use both postprocess (post-cook) lethality steps that demonstrate significant reductions in Listeria and antimicrobial ingredients that either eliminate or control Listeria.

In December 2002 and June 2003, provisions were published that could reduce a high-medium-risk product category, i.e., hotdogs and RTE deli meats, to a low-risk grouping. This would lead to a reduction in the amount of product testing needed if validated pathogen reduction and control measures are implemented by companies.

Additional initiatives that address pathogen reduction have been investigated by researchers at Oklahoma State University. One area that has garnered considerable interest is the postprocess surface pasteurization of RTE meat and poultry products. Many RTE products experience considerable exposure to environmental conditions after they are removed from cook-in bags, either for further processing, such as smoke flavor processing, or for transfer into retail packaging bags.

While exposed, the products can acquire incidental contamination from racks and trays, workers' hands, food contact surfaces or aerosol sprays. Additional thermal processing for 1 minute to 3 minutes, immediately before or after the final packaging is in place, can reduce or eliminate surface pathogens and significantly reduce the risk to consumers. Such an approach can be used as an effective pathogen reduction alternative in the fight against foodborne pathogen contamination of RTE meat and poultry products.

Further information. Peter Muriana, Food and Agricultural Products Research and Technology Center, Oklahoma State University, Room 109, Stillwater, OK 74078; phone: [phone]; fax: [phone]; email: [e-mail].