- Author: Jeannette E. Warnert
Scientists from Cooperative Extension programs at Rutgers University, University of Arizona and University of California worked collaboratively on lettuce field trials that have shown applying a protein to lettuce can reduce the risk of bacterial contamination, according to a story in The Packer. The work also shows that the treatment prolongs the shelf life of processed lettuce used in bagged salads.
The naturally occurring protein the researchers are studying, harpin, triggers a natural defense mechanism in plants, something like the broad spectrum immune response in animals, according to a US Environmental Protection Agency factsheet. While most pesticides act directly on the target pest, harpin causes a protective response in the plant that makes it resistant to a wide range of fungal, bacterial, and viral diseases.
The EPA says, when used properly, harpin has no detrimental environmental effects and its impact on human health is minimal to nonexistent.
The Packer article, written by Dawn Withers, said scientists sprayed harpin on lettuce at different strengths to test areas in California, New Jersey and Arizona five days before harvest. A control area at each site was treated with tap water. They found harpin's greatest effect was longer shelf life when larger doses were applied.