Effects of Atmosphere on Survival and Growth of Pathogens in Fresh-Cut Produce

Increasing consumption of fresh produce has been paralleled by an increase in food poisoning outbreaks, some linked to fresh-cut products. Safety assurance occurs during growing and harvesting, processing, packaging and storage. Safe atmospheres are relevant to packaging and storage decisions and controls. There are potential safety issues associated with both intended and unintended modified atmospheres (MAs). O-2-depleted atmospheres used commercially to control enzymatic browning in fresh-cut lettuce, enhanced Listeria monocytogenes growth under mild abuse temperatures, but not at 3 degrees C. Unintended anoxic atmospheres with high levels of CO2 also selectively favoured growth of Listeria monocytogenes and Salmonellae at abuse temperatures. Growth of E. coli O157:H7 was unaffected by MAs found in fresh-cut products. The data have implications for product temperatures during distribution and retail, modest shelf life, greater attention to optimised packaging, application of alternative technology for control of enzymatic browning, and for effective sanitation of manufacturing facilities.