Influence of cell history on the subsequent inactivation of Campylobacter jejuni during cold storage under modified...

Worldwide, Campylobacter infections are the main cause of human bacterial enteritis and broiler meat is considered as the most important source of human campylobacteriosis. Some mitigation strategies have been focused on reduction of Campylobacter at the slaughtering steps. This study aimed to determine the influence of consecutive stresses inspired by slaughtering steps on the subsequent inactivation of Campylobacter jejuni during cold storage under different modified atmospheres. Using a full experimental design, three strains of C. jejuni of poultry origin were submitted to consecutive heat (46°, 50° or 54 °C for 4 min) and cold (-4° or 3 °C for 2 h) stresses by plunging cultures into baths at appropriate temperatures. Cultures were then stored at 6 °C during seven days under modified atmospheres (70% O₂/30% CO₂ or 50% CO₂/50% N₂). Inactivation of C. jejuni induced by cold storage was shown to depend significantly (P < 0.0001) upon the heat stress previously applied. It was shown to be the highest under the atmosphere enriched in oxygen, after application of 54 °C. Strain inactivation variability was also quantified. These results show that consecutive stresses influence further inactivation of C. jejuni during storage and consequently the contamination level at consumer's plate.