St. Paul, Minn. (January 27, 2003)—Salmonella, E. coli, shigellosis, hepatitis A, and Norwalk—these foodborne diseases can produce symptoms that run from the mild to life threatening. The young and old are particularly vulnerable and while consumption of beef and poultry have been the most common sources of such infections, fresh fruits and vegetables are being increasingly implicated in such outbreaks; so much so that plant disease scientists are now taking a closer look at this issue.
“Historically, human pathogens like E. coli and Salmonella have rarely been associated with plants, so plant disease scientists have not looked at them directly,” says J.W. Buck, a plant pathologist at the University of Georgia. But that is changing, says Buck, as such incidences continue to increase.
Buck says there is no single reason why the number of reported produce-related outbreaks in the U.S. per year doubled between 1973 and 1987 and 1988 and 1992 and why they continue to rise. Possible explanations include the simple fact that we are eating more fruits and vegetables than ever before. But experts agree that there is more to it than that and that our food production practices likely bear some responsibility.
But identifying the exact point along the way, from field to grocery store, where a strawberry or head of lettuce, for example, might have become contaminated can be difficult, if not impossible. Unlike other commodities such as beef and chicken, which are rigorously inspected, methods to detect pathogens on fresh produce are less advanced and the sporadic nature of most contamination further limits the effectiveness of testing.
“Plant disease scientists know a lot about how other microorganisms interact with plants and the environment to create an outbreak,” says Buck. “This same knowledge can be applied to human pathogens as well. An exchange of research tools and experiences between plant pathologists and food microbiologists could result in tremendous advances towards managing foodborne diseases related to produce consumption.”
According to Buck, one impediment to this kind of research, however, is that plant pathology laboratories currently lack the appropriate facilities for working with human pathogens, which are considered biosafety hazards. Until such changes can be made, says Buck, plant pathology models and practices, such as integrated pest management, that have worked well in controlling other plant diseases would likely work in helping to minimize the risk of human disease as well. Says Buck, “No doubt plant disease scientists can, and should, play a more significant role in food safety issues in the future.”
The microbiological safety of fruits and vegetables is the subject of the APS feature story and can be found at www.apsnet.org/publications/apsnetfeatures/Pages/MicroSafety.aspx. The American Phytopathological Society (APS) is a nonprofit, professional scientific organization dedicated to the study and control of plant disease with 5,000 members worldwide.