Prevalence and diversity of Campylobacter species in Saskatchewan retail ground beef

Abstract

The primary objective of this study was to investigate the prevalence of Campylobacter spp. DNA by PCR in retail ground beef sold in Saskatchewan, Canada, and to identify the presence of individual Campylobacter species (C. coli, C. curvus, C. fetus, C. hyointestinalis, C. jejuni, C. rectus, and C. upsaliensis) using real-time quantitative PCR (qPCR). Secondary objectives were to assess potential differences in the prevalence of Campylobacter between ground beef offered for sale during cold and warm seasons as well as that offered for sale fresh and frozen, to investigate any association between the presence of Campylobacter spp. DNA and E. coli and/or aerobic bacterial counts, and finally to compare the prevalence of Campylobacter spp. DNA in ground beef originating from different production and retail environments. Out of the 309 total samples included in the study, 50 (16.2%) samples tested positive for Campylobacter spp. DNA, while 49 (15.9%) samples were determined positive for up to five individual species. Collectively, these assays determined that 14 (4.5%) samples were positive for C. coli, 11 (3.6%) for C. curvus, 6 (1.9%) for C. fetus, 24 (7.8%) for C. hyointestinalis, 12 (3.9%) for C. jejuni, 6 (1.9%) for C. rectus, and 9 (2.9%) for C. upsaliensis. There were 27 (8.7%) samples that were positive at the genus level that did not test positive for any of the seven Campylobacter species investigated (suggesting an alternate Campylobacter species). Also, 26 (8.4%) samples generated positive results by one of the species-specific qPCR assays, but returned no product in the conventional genus-level assay (suggesting a higher sensitivity for the species-specific qPCR assays). There was no significant association between the presence of Campylobacter spp. in Saskatchewan retail ground beef and any of the investigated risk factors.