Meat juice contributes to the stability of ethanol adaptation in Salmonella enterica serovar Enteritidis

Stability assessment of observed tolerance phenotypes is integral in understanding stress adaptation in food-borne pathogens. Therefore, the current work was carried out to determine whether ethanol adaptation induced by exposure to 5 per cent ethanol for 60 min is a stable phenomenon in Salmonella enterica serovar Enteritidis. The capacity of Salmonella Enteritidis (S. Enteritidis) to maintain the acquired ethanol adaptation in the absence of sublethal ethanol stress was investigated at 37 degrees C, 25 degrees C or 4 degrees C in Luria-Bertani broth and two types of meat juice. It was found that ethanol adaptation was completely reversed within 40 min at 37 degrees C or within 60 min at 25 degrees C, but was stable at 4 degrees C for at least 48 h in the broth assay. Ethanol adaptation was retained in chicken juice during 60-min incubation at 25 degrees C or 48-h incubation at 4 degrees C. Moreover, exposure to pork juice stored at either 25 degrees C or 4 degrees C significantly (P<0.05) increased the ethanol tolerance of ethanol-adapted cells. Collectively, these findings suggest that ethanol adaptation stability in S. Enteritidis under cold conditions and in meat juices should be taken into account when conducting a comprehensive risk analysis during food processing.