Invasive potential of sub-lethally injured Campylobacter jejuni and Salmonella Typhimurium during storage in chicken meat juice

Abstract

Campylobacter jejuni and Salmonella Typhimurium are major foodborne pathogens that cause gastrointestinal infections in humans. Humans can acquire these bacteria through the consumption of contaminated poultry meat. In many countries, during poultry meat processing, chicken carcasses are often treated with sanitizers to reduce the load of food spoilage and foodborne pathogens. The European Union, however, currently does not permit the use of sanitizers for chicken meat processing. The survivability and virulence of sub-lethally injured bacteria after exposure to chemical decontamination, however, is poorly understood. Here, we investigated the survivability and invasion potential of Campylobacter jejuni and Salmonella Typhimurium following exposure to chlorine and acidified sodium chlorite (ASC) during storage in chicken meat juice (CMJ). Campylobacter jejuni and Salmonella Typhimurium were stored in CMJ under refrigeration (5 °C) following exposure to either chlorine or ASC. Bacterial culturability, motility, and invasive capacity were subsequently investigated. Changes in the expression of Campylobacter and Salmonella specific stress response and virulence genes were also investigated. The results revealed that CMJ facilitated the survival of both Campylobacter and Salmonella following exposure to chlorine but not ASC. Both the chlorine and ASC reduced bacterial invasiveness, motility, and culturability of Campylobacter jejuni but not Salmonella Typhimurium. Bacterial stress response and virulence genes in Campylobacter jejuni (rpoB, sodB, flaG, flaA, cadF, racR) and Salmonella Typhimurium (rpoH, rpoS, hilA, fimH, spvR, avrA) were upregulated over time, indicating an increase in virulence potential. This study suggested that sub-lethally injured Campylobacter jejuni and Salmonella Typhimurium in CMJ remain a significant risk in the food chain due to the likelihood of cross-contamination while handling chicken meat. Furthermore, the greater bactericidal effects of ASC can reduce the risk of contamination.