Prevalence of Shiga toxin-producing Escherichia coli (STEC) O157:H7, Six non-O157 STECs, and Salmonella on beef carcasses in Provincially Licensed Abattoirs in Alberta, Canada

Abstract

From January to December 2016, Alberta Agriculture and Forestry (AAF) conducted a provincial survey of selected pathogens and indicator organisms on beef carcasses processed at Provincially Licensed Abattoirs (PLAs) in Alberta. The survey was conducted in seven small and medium scale slaughterhouses located in southern and northern Alberta that process beef cattle and cows. Paired samples were collected from the same carcass immediately after hide removal (pre-evisceration n = 401) and at pre-chill (n = 402) after application of a carcass wash and/or anti-microbial interventions. Swab samples were screened for the presence of Shiga toxin-producing Escherichia coli (STEC) O157:H7, six non-O157 STECs (O26, O45, O103, O111, O121 and O145), and Salmonella. In addition, samples were enumerated for indicator organisms (aerobic colony count (ACC), Enterobacteriaceae, coliforms, and generic E. coli). At pre-evisceration, 30 samples (7.4%) were confirmed positive for E. coli O157:H7; 13 samples (3.2%) were confirmed positive for non-O157 STEC; and 7 samples (1.7%) were confirmed positive for Salmonella. Pre-chill swabs had 21 samples (5.2%) positive for E. coli O157:H7, 16 samples (3.9%) positive for non-O157 STEC, and 1 sample (0.2%) positive for Salmonella. At pre-chill the prevalence of Salmonella was significantly lower (P < 0.05) than at pre-evisceration. For ACC, Enterobacteriaceae, coliforms and generic E. coli log means were significantly lower at pre-chill than pre-evisceration (P < 0.05). The level of ACC, generic E. coli, coliforms and Enterobacteriaceae showed a reduction of 0.3 log CFU/cm2, 0.5 log CFU/cm2, 0.5 log CFU/cm2 and 0.4 log CFU/cm2 respectively.