Incidence of Salmonella on fresh fruits and vegetables affected by fungal rots or physical injury

Enriched wash from healthy and decayed portions of 341 fruits and vegetable s collected in the marketplace and affected by fungal rots were tested for suspected Salmanella appearing as black, hydrogen sulfide-positive colonies on Salmonella-Shigella agar incubated at 37 degrees C. Suspected Salmonell a occurred in 20.2% of healthy and in 26.4% of decayed portions, two-thirds of which were caused by Alternaria and Botrytis. In a similar analysis of 121 samples with mechanical injuries, in which two-thirds were gouges, cuts , and bruises, there were no significant differences in Salmanella incidenc e between injured and uninjured portions. Of 332 suspected Salmonella rando mly isolated from healthy and decayed or injured portions, 17 (5.1%) were c onfirmed as Salmonella by physiological and serological testing. When tomat o, potato, and onion tissues were inoculated with Salmonella typhimurium, p opulations of that bacterium increased by one to two logs over a 48-h incub ation at room temperature. Coinoculation of tissues with S. typhimurium and Botrytis or Rhizopus, but not Alternaria or Geotrichum, caused a statistic ally significant increase in populations of Salmonella compared with the co ntrols.