Salmonella growth and survival in rockmelon rind under different storage conditions

Consumption of fresh produce has been implicated in several serious outbreaks of food-borne enteric diseases in recent years, leading to renewed scrutiny of the supply chain to identify routes of contamination, improve safety assurance systems, and develop control strategies. Contaminated rockmelon (Cucumis melo L. var. reticulatus Naud.) has been associated with at least one large multi-state outbreak of salmonellosis in Australia and three in the United States since 2006. Rockmelons are conventionally stored at 5°C prior to retail; however some new rockmelon cultivars such as LSQUOCarribean GoldRSQUO require storage at 13°C for 2-3 days to enable softening to an acceptable level of flesh firmness. Warm storage conditions may be conducive to Salmonella growth, which is known to adhere within the netted surface of the rind. In this paper, we present some preliminary research findings that confirm that raising the temperature of postharvest cool storage prior to retail from 5 to 13°C increased the persistence of Salmonella Typhimurium on contaminated rockmelon rind. A systematic analysis of the supply chain using a risk analysis framework to identify key phases and factors contributing to microbial food safety risk is needed to optimise monitoring and control measures that will mitigate fresh produce safety risks.