Posted: April 13th, 2012 - 12:52pm
Source: The Packer

Salmonella can rebound in produce in humid storage before or after washing.
Steven Pao, a professor in food safety and microbiology at Virginia State University’s agricultural research station in Petersburg, and other researchers studied how spray washing on rollers or revolving brushes influences salmonella rebound on jalapeño peppers and roma tomatoes.
The study, published in the April issue of Foodborne Pathogens and Disease, discovered significant rebound of salmonella populations on peppers and tomatoes stored for more than three days at 59 degrees.
Water washing contaminated peppers decreased salmonella counts by half and roller and brush washing of contaminated tomatoes decreased salmonella counts from 3.7 logs to 1 log.
The study showed the lack of temperature control following spray rinsing or rinsing and brushing of peppers and tomatoes may allow residual salmonella populations to rebound on the washed produce during storage, researchers wrote.
At 69.8 degrees and 95 degrees, the levels of salmonella on produce surfaces increased more than 2 log cycles.
The study demonstrates that storing below 50 degrees remains adequate for preventing salmonella population rebound and proliferation on washed and non-washed produce.
“Clearly, irrespective of mechanical spraying and brushing action, the pathogen population can rebound on tomatoes under conducive conditions,” researchers wrote.