Differential attribution of contamination sources for beef and pork produced at the same processing facility

To improve the microbial quality and safety of meat, information on contamination source during production in processing facilities is of paramount importance. This study examined the microbiological condition of chilled carcasses (CH), primal cuts (PC), trimmings (TM), conveyor belt, stainless steel shelves, cutting tables, knives, and mesh gloves during the routine production of beef and pork at a meat packing facility for 10 weeks. Total aerobic counts (TAC) from CH of the two species were similar at 2.19 ± 0.91 (beef) and 2.26 ± 0.62 log CFU/1000 cm² (pork). However, TAC for pork PC and TM were 1 log higher than that for CH (P <0.05), while no such differences occurred in beef. TAC for all equipment except for knives differed between the two livestock species, with those involved in the pork fabrication being 0.5-0.7 log unit higher (P < 0.05). Compared to CH, equipment showed higher frequency of Enterobacteriaceae recovery for pork, but the same was not true for beef. Gloves and knives were significant sources of E. coli for pork production. Between the two animal species, beta diversity differed for CH, meat and fixed equipment, but not for personal equipment. Equipment surfaces were the major driver for microbial community differences between the meat of the two animal species. As well, the microbial community on meat and fixed equipment differed with sampling time but not on CH or personal equipment. Pseudomonas and Acinetobacter were the most abundant bacterial genera overall. For beef, Brevundimonas, Clostridium, Macrococcus, Pseudomonas, and Stenotrophomonas were attributable to equipment surfaces. For pork, equipment surface contamination was for Acinetobacter, Peptostreptococcus, Pseudomonas, Stenotrophomonas, and Trueperella.