Metabiosis of proteolytic moulds and Salmonella in raw, ripe tomatoes.

AIMS

The aim of this study was to determine the survival and growth characteristics of Salmonella enterica in sound and chill-injured tomatoes as influenced by co-infection with proteolytic moulds.

METHODS AND RESULTS

Sound (not chill injured) raw, ripe tomatoes (Lycopersicon esculentum Mill. 'Roma') were inoculated with a five-serotype mixture of S. enterica and/or Alternata alternata (two strains), Cladosporium herbarum and C. cladosporioides. Simultaneous and delayed (3 days) inoculation of tomatoes with Salmonella and each mould was studied. Growth of moulds in sound tomatoes stored at 15 and 25 degrees C for up to 10 days was accompanied by increased pH of radial pericarp tissue (pulp), which enhanced the growth of Salmonella. Growth of moulds and Salmonella at 25 degrees C was enhanced in chill-injured tomatoes compared with sound tomatoes.

CONCLUSIONS

Growth of proteolytic moulds in tomatoes stored at conditions simulating those commonly used in commercial postharvest storage and handling promotes the growth of Salmonella that may be an incidental contaminant.

SIGNIFICANCE AND IMPACT OF THE STUDY

Discarding tomatoes that are infected by moulds is important in handling and minimal processing practices designed to minimize the risk of human salmonellosis.