Scientists Seek Strategies to Safeguard Fresh Sprouts

Fresh sprouts make a crisp, crunchy and healthful addition to sandwiches, salads, soups, omelets and other dishes. Now, studies by Agricultural Research Service scientists may lead to new ways to help protect raw sprouts from attack by E. coli, Salmonella or other pathogenic microorganisms.

These microbes can flourish in the warm, moist indoor environment in which seeds are induced to sprout, according to microbiologist Amy O. Charkowski at Albany, Calif. Seeds purchased by "sprouters"--the growers who run the indoor operations that yield sprouted seeds--may already be contaminated by microbes harbored in irrigation water, fertilizer, or bird or mouse droppings, according to Charkowski. She is with the Food Safety and Health Unit at the ARS Western Regional Research Center in Albany.

In laboratory studies with radish, alfalfa, broccoli and mung bean sprouts, Charkowski wants to determine what compounds produced naturally by the sprouts--such as amino acids--nurture the attacking microbes. She will then determine whether harmless bacteria might be applied to the sprouts to deprive the food-poisoning microbes of the compounds vital to their attack.

In other experiments, Charkowski intends to pinpoint genes that Salmonella turns on--or "expresses"--when it colonizes sprouts. Once scientists know which Salmonella genes are crucial to successful attacks, the researchers may be able to develop a strategy to activate and amplify sprouts’ natural protective mechanisms.

Charkowski anticipates that the genes Salmonella activates are likely the same as those it uses when it invades other fresh produce--and perhaps meats and poultry. If that is the case, food safety strategies developed from the sprout research may also help protect these other foods from Salmonella.

ARS is USDA’s chief research agency.

Scientific contact: Amy O. Charkowski, Food Safety and Health Research Unit, ARS Western Regional Research Center, Albany, Calif.; phone (510) 559-5647, fax (510) 559-5948, amy@pw.usda.gov.