Salmonella prevalence in bovine lymph nodes differs among feedyards.

Lymphatic tissue, specifically lymph nodes, is commonly incorporated into ground beef products as a component of lean trimmings. Salmonella and other pathogenic bacteria have been identified in bovine lymph nodes, which may impact compliance with the Salmonella performance standards for ground beef established by the U.S. Department of Agriculture. Although Salmonella prevalence has been examined among lymph nodes between animals, no data are currently available regarding feedyard origin of the cattle and Salmonella prevalence. Bovine lymph nodes (279 superficial cervical plus 28 iliofemoral = 307) were collected from beef carcasses at a commercial beef harvest and processing plant over a 3-month period and examined for the prevalence of Salmonella. Cattle processed were from seven feedyards (A through G). Salmonella prevalence was exceptionally low (0% of samples were positive ) in cattle from feedyard A and high (88.2%) in cattle from feedyard B. Prevalence in the remaining feedyards ranged widely: 40.0% in feedyard C, 4.0% in feedyard D, 24.0% in feedyard E, 42.9% in feedyard F, and 40.0% in feedyard G. These data indicate the range of differences in Salmonella prevalence among feedyards. Such information may be useful for developing interventions to reduce or eliminate Salmonella from bovine lymph nodes, which would assist in the reduction of Salmonella in ground beef.

Alternative cooling procedures for large, intact meat products to achieve stabilization microbiological performance standards.

Achieving the U. S. Department of Agriculture, Food Safety and Inspection Service (USDA-FSIS) stabilization microbiological performance standards for cooling procedures proves to be challenging for processors of large, whole-muscle meat products. This study was conducted to determine if slower cooling times than those provided by USDA-FSIS guidance will comply with the performance standard for Clostridium perfringens. Large (9 to 12 kg) cured bone-in hams (n = 110) and large (8 to 13 kg) uncured beef inside rounds (n = 100) were used. Stabilization treatments extended times to reduce internal product temperature from 54.4 to 26.7°C (hams and rounds) and from 26.7 to 7.2°C (for hams) and 26.7 to 4.4°C (for rounds). Control treatments, defined by current USDA-FSIS Appendix B guidelines, and a "worst-case scenario" treatment, in which products were cooled at room temperature (approximately 22.8°C) until internal product temperature equilibrated, were used. For both hams and rounds, stabilization showed less than 1-log growth of C. perfringens for all treatments, with the exception of the worst-case scenario for rounds. As expected for products cooled at room temperature, there was >1-log growth of C. perfringens reported for rounds, and the addition of curing ingredients to hams had an inhibitory effect on the growth of C. perfringens. The results demonstrate that industry may have increased flexibility associated with cooling large, whole-muscle cuts while still complying with the required stabilization microbiological performance standards.