Low Prevalence and Concentrations of Campylobacter Detected on Retail Chicken Breasts

Since 2014, Campylobacter has been the leading bacterial cause of foodborne illness in the United States, resulting in millions in economic losses each year and strains on public health. Chicken, the most consumed meat in the US, is the primary source of Campylobacter infection in humans, accounting for 50 - 90% of all cases. To survive food processing stressors like oxidative and cold stress, Campylobacter enters a viable but nonculturable (VBNC) state, where cells remain intact (viable) but cannot grow in conventional culture media within the prescribed time (nonculturable). This presents a food safety challenge since growth in selective media, which only determines the culturable cells, is required for the detection of Campylobacter using standard microbiological methods. Culture-independent detection methods like viability quantitative polymerase chain reaction (qPCR) have been developed to overcome this challenge and detect both culturable and nonculturable viable cells. Here, we applied both culture-based methods and viability qPCR to assess the occurrence and levels of Campylobacter on 209 retail skinless boneless chicken breasts processed in at least eight U.S. states. Culture-based enrichment yielded isolates for 15 samples, with whole genome sequencing identifying isolates from four samples as C. jejuni, eight samples as Acinetobacter spp., one as Micrococcus luteus, and one as Escherichia coli, resulting in a 1.9% prevalence of Campylobacter on retail skinless boneless chicken breast. Spread plating on selective media and viability qPCR did not detect Campylobacter in any of the tested samples, suggesting that concentrations were below the limit of detection of these methods.