Changes in the field can cut food contamination

"This is going to help make produce safer," says Laura Strawn. "We could significantly reduce risk of contamination through changes that occur a few days before the harvest." (Credit: ilovebutter/Flickr)

Small shifts in agricultural practices can increase or reduce the risk of salmonella and listeria contamination on produce, new research shows.

For example, applying manure within a year of harvesting produce boosts the odds of contaminating a field with salmonella, which is the biggest single killer among the foodborne microbes, report the researchers. In addition, irrigating fields within three days and cultivating fields within a week of harvest significantly raised the risk of Listeria monocytogenes contamination.


However, establishing a buffer zone between fields and potential pathogen reservoirs, such as livestock operations or waterways, was found to be protective against salmonella the study reveals.

“This is going to help make produce safer,” says first author Laura Strawn, a graduate student in the field of food science. “We could significantly reduce risk of contamination through changes that occur a few days before the harvest.”

Many of the risk factors were influenced by when they were applied to fields, which suggests that adjustments to current practices may reduce the potential for contamination with minimal cost to growers, says Strawn.

Foodborne illness sickens an estimated 9.4 million people and kills about 1,300 annually in the United States, according to the Centers for Disease Control and Prevention. Produce accounts for nearly half the illnesses and 23 percent of the deaths.

“The research is the first to use field collected data to show the association between certain management practices and an increased or decreased likelihood of salmonella and L. monocytogenes,” says Strawn.

“These findings will assist growers in evaluating their current on-farm food safety plans (e.g., ‘Good Agricultural Practices’), implementing preventive controls that reduce the risk of preharvest contamination, and making more informed decisions related to field practices prior to harvest. Small changes in how produce is grown and managed could result in a large reduction of food safety risks.”

The US Department of Agriculture supported the study, which appears in Applied and Environmental Microbiology.

Source: Cornell University