RALEIGH — North Carolina State University scientists are looking for Salmonella on tomatoes and around tomato production areas. What they find could help farmers grow tomatoes that have a decreased likelihood of carrying Salmonella.
Salmonella is a bacterium that can contaminate food and make people who eat that food sick. Healthy adults infected with Salmonella typically experience several days of diarrhea, fever, vomiting and abdominal cramps. However, for the very young, very old and people with compromised immune systems, the effects can be severe and occasionally result in death.
Salmonella is most often associated with fecal material, and fecal material is present in the natural environment, associated with wild and domestic animals, including reptiles and birds, even humans. Though it is known that Salmonella is associated with fecal material, it is not known where in the agricultural production environment Salmonella is.
The team is made up of Dr. Chris Gunter, assistant professor of horticultural science; Dr. Lee-Ann Jaykus, William Neal Reynolds Distinguished professor of food science; Dr. Otto “Chip” Simmons III, research assistant professor of biological and agricultural engineering; Dr. Penelope Perkins-Veazie, professor of horticultural science; and Diane Ducharme, a graduate student working toward a doctorate in horticultural science.
The team is beginning the second year of a three-year study that partners with the U.S. Food and Drug Administration.
“The purpose of the study is to locate environmental reservoirs of Salmonella,” says Gunter. “These bacteria can exist in the environment. We want to know where.”
Much of the search for Salmonella rests with Ducharme. During the growing season, Ducharme regularly collects samples from three tomato production areas in different parts of the state. She also collects leaves and blossoms from tomato plants, soil and any fecal matter that might be in the area. Ducharme also collects water and sediment samples from two streams and a pond used for irrigation in the areas she samples. Those water samples may be particularly important.
The FDA has identified surface water as a potential risk for contaminating crops with Salmonella. Surface water is open to the environment and may be prone to fecal contamination. It’s used in crop production for things like planting, pesticide application, irrigation and evaporative cooling. Surface water, if it is contaminated, would be a good vehicle for transporting a pathogen like Salmonella to tomato plants.
Farmers should benefit from the study if, as intended, it reveals some of Salmonella’s secrets. Rather than requiring a range of actions on the part of farmers that may or may not reduce the possibility of Salmonella contamination, the FDA will be able to use study results to focus crop production rules on actions that research indicates will reduce the chance of contamination.
Gunter adds, “Ultimately, we hope that we will gain a better understanding of where that pathogen exists, how it moves into crop production areas and then how to mitigate any risk that may be associated with the pathogen.”