WASHINGTON — University of Georgia researcher Mike Doyle said that his research is pointing to a new possible culprit in the contamination of fresh- cut produce: the coring knives used to cut and core lettuce in the fields during harvesting.
At the Food Safety & Security Summit held here March 19, Dr. Doyle said that preliminary research is showing that the process of dipping knives into contaminated soil when cutting and coring lettuce heads in the fields may push bacteria into the lettuce. In experiments, researchers inoculated soil with heavy doses of E. coli and cut lettuce sequentially with the same blade and found the bacteria in the lettuce, Dr. Doyle, director of University of Georgia's Center for Food Safety, said at the meeting.
The good news is that so far, his research, funded by grants from Fresh Express, is not demonstrating the theory that Iceberg lettuce internalizes E. coli-tainted soil in its leaves. This led Dr. Doyle to take a closer look at the threat of bacteria invading the lettuce by coring knives.
Will Daniels, vice president of quality, food safety and organic integrity for Earthbound Farm, who also spoke at the meeting, said that his company was "shaken awake" by the 2006 spinach outbreak, completely changing its food- safety system. Despite the company's multiple-hurdle system that incorporates a range of firewalls including raw product testing, Earthbound Farm has "had a positive on the finished product side," he said. The laboratory with which the company is working predicted that the processor would get positives regardless of upstream measures, but Mr. Daniels said that the company's procedures worked to identify and eliminate the product.
All producers need to conduct hazard analyses in the fields, he said, and the company's test-and-hold system for raw and finished products is an extremely important precaution for fresh-cut companies.
Read the full Produce News story here.