Salmonellosis outbreaks in the United States due to fresh produce: sources and potential intervention measures

Foodborne Salmonella spp. is a leading cause of foodborne illness in the United States each year. Traditionally, most cases of salmonellosis were thought to originate from meat and poultry products. However, an increasing number of salmonellosis outbreaks are occurring as a result of contaminated produce. Several produce items specifically have been identified in outbreaks, and the ability of Salmonella to attach or internalize into vegetables and fruits may be factors that make these produce items more likely to be sources of Salmonella. In addition, environmental factors including contaminated water sources used to irrigate and wash produce crops have been implicated in a large number of outbreaks. Salmonella is carried by both domesticated and wild animals and can contaminate freshwater by direct or indirect contact. In some cases, direct contact of produce or seeds with contaminated manure or animal wastes can lead to contaminated crops. This review examines outbreaks of Salmonella due to contaminated produce, the potential sources of Salmonella, and possible control measures to prevent contamination of produce.