Survival of Salmonella Montevideo on tomato leaves and mature green tomatoes

Survival of Salmonella Montevideo on tomato leaf and mature green tomatoes was examined. When spiked on the surfaces of excised leaves from greenhouse tomato plants, Salmonella Montevideo survived poorly if the leaves were allowed to dry. After spot inoculation of 6.6 log CFU per leaflet and incubation for 48 h at 60% relative humidity, the leaflets were dried, and surviving Salmonella were reduced 2.8 to 3.7 log CFU per leaflet. However, when leaves spiked with Salmonella were supported on hydroponic nutrient medium and incubated at 100% relative humidity, there was no significant reduction of surviving bacteria for at least 6 days. Exposure of mature green tomatoes to ethylene (100 ppm at 100% relative humidity and 20 degreesC for 6 days) did not significantly affect the survival of Salmonella on their surfaces. The significance of these data to pre- and postharvest safety of tomato is discussed.