부산대학교 도서관

The Agricultural Marketing Service procures boneless and ground beef for federal nutrition assistance programs. It tests procured beef for concentrations of standard plate counts (SPCs), coliforms, and Escherichia coliand for the presence of Salmonellaand Shiga toxin–producing E. coli. Any lot exceeding predefined critical limits (100,000 CFU g−1for SPCs, 1,000 CFU g−1for coliforms, and 500 CFU g−1for E. coli) or positive for Salmonellaor Shiga toxin–producing E. coliis rejected for purchase. Between 1 October 2013 and 31 July 2017, 166,796 boneless beef lots (each approximately 900 kg) and 25,051 ground beef sublots (each approximately 4,500 kg) were produced. Salmonellawas detected in 1,955 (1.17%) boneless beef lots and 219 (0.87%) ground beef sublots. Salmonellasample size increased from an individual 25-g sample to a co-enriched 325-g sample on 1 March 2015. Salmonellapresence was associated with season (lowest in spring), larger sample size, and increased log SPC in boneless and ground beef. Increased log E. coliwas associated with Salmonellapresence in boneless beef, but not ground beef. SalmonellaDublin was the most common serotype in boneless beef (743 of 1,407, 52.8%) and ground beef (35 of 171, 20.5%). SalmonellaDublin was generally associated with lower indicator microorganism concentrations compared with other Salmonellaserotypes as a group. Relative to other Salmonella, SalmonellaDublin was associated with season (more common in spring) and smaller sample size in boneless and ground beef. Decreased log SPCs and log coliforms were associated with SalmonellaDublin presence in boneless beef, but not in ground beef. Differential associations between SalmonellaDublin and other serotypes with indicator microorganisms were strong enough to cause confounding and suggest that the presence of SalmonellaDublin needs to be accounted for when evaluating indicator performance to assess Salmonellarisk in boneless and ground beef.