Survival of Salmonella enteritidis and Listeria monocytogenes on salad vegetables

The influence of initial head-spaces of air – 4.9% CO2/2.1% O2/93% N2 and 5% CO2/5.2% O2/89.8% N2 – on Salmonella enteritidis and Listeria monocytogenes, and on microbial association with shredded carrots and lettuce was studied at 4 °C. Both these pathogens survived but did not grow in any vegetable regardless of the packaging system used. Total viable count, lactic acid bacteria and pseudomonads were also monitored. Lactic acid bacteria were the predominant organisms in all samples. The pH dropped significantly during the storage of vegetables.