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Joseph
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Research
U.S. consumers are eating more fresh fruits and vegetables. Along with this increase comes an increase in disease transmitted by fresh produce.
Since consumers are demanding fresh produce year-round, consumers are buying produce shipped from other countries that doesn't undergo any treatments to completely remove pathogenic microorganisms. Most produce is washed in chlorinated water before distribution to stores. That may note be enough. Pathogenic microorganisms survive on fresh produce that is washed with chlorinated water. Joe Frank, a UGA scientist has done research using E. coli O157:H7 and Salmonella on iceberg lettuce.
Salmonella
and E. coli O157:H7 both attach to lettuce leaf at breaks in the
surface cuticle. The cuticle is a waxy layer the keeps moisture inside
the leaf. It also repels pathogenic bacteria. The pathogens penetrate
into the leaf through holes in the leave through which the lettuce respires,
or stoma.
Many consumers like the convenience of precut salad ingredients. Pathogenic microorganisms readily attach to the cut edges of the lettuce and actually penetrate into the cut.
Pathogens that penetrate into the leaf through stomata or at cut edges aren't removed or killed by washing with chlorinated water. Washing with chlorinated water does reduce the total amount of pathogenic bacteria on the lettuce by removing or killing most of those bacteria that aren't attached at protective sites or are present in soil on the leaf surface. Washed produce is safer than unwashed products.
This research gave the food industry valuable information to develop washing treatments that target bacteria normally not removed by current technology, helping them market safer fresh produce.
