PLACE

Texas Tech University, Lubbock, TX

PURPOSE

1. Determine and quantify the reduction of growth of E. coli O157:H7 and Salmonella spp. on beef tissue following two chilling methods (water spray chilling and dry chilling) used by small processing plants.
2. Determine the use of dry chilling as a Critical Control Point (CCP).

Summary

Small processors are continually striving to explore cost effective means to reduce pathogenic bacteria on beef carcasses. Currently, small beef or custom beef processors allow beef carcasses to dry age for 28 days to improve beef palatability. The results from this study have shown that dry chilling for 21 days is an effective intervention in reducing E. coli O157:H7 and Salmonella spp. on fresh beef carcasses compared to conventional water spray chilling/wet ageing. This recommendation is compared to Buege and Ingram (2003) which suggests a 6-day aging of carcasses and critical limits of cooler temperature, as well as days of aging. Although a decrease in recovery was seen across both pathogens as well as both treatments, the recommendation from the above results show that at 21 days of aging beef tissues can achieve an approximate 4-log reduction of pathogenic bacteria by dry chilling.

Benefits

This study reinforces the advantage of dry chilling/ageing of beef carcasses in reducing the levels of E. coli O157:H7 and Salmonella spp. when compared to the conventional water spray chilling/wet ageing. Plants will, however, need to validate that their methodology achieves these parameters. This research should decrease their operating costs while helping them to ensure food safety and public health protection.