Internalization of Salmonella enterica by tomato fruit

Since 1990, several outbreaks of foodborne illness have been associated with the consumption of raw tomatoes. Various serovars of the bacterial pathogen, Salmonella enterica, were responsible for these illnesses. Fruits and vegetables are not a normal niche for mammalian pathogens. Hypotheses concerning introduction of Salmonella into tomatoes range from contamination in the field or greenhouse to direct or cross-contamination during harvest, handling and preparation of tomato as a raw agricultural commodity. Many different reports have shown that Salmonella can not only survive in tomato fruit but also proliferate from small, relatively inconsequential populations to numbers known to incite illness even in healthy individuals.Herein, production, harvest and handling of fresh market tomatoes are evaluated in terms of how Salmonella might contaminate this crop. Physical principles are emphasized, whereas biological factors are included where appropriate. Salmonella is viewed as a bacterium that is affected by the same physical principles affecting bacteria naturally occurring in the environment surrounding tomato fruit as well as tomato plants during production, harvest and handling.