UGA researchers found that pathogens, like salmonella, can survive for at least six months in cookies and crackers. The recent study was prompted by an increased number of outbreaks of foodborne diseases linked to low-water-activity, or dry, foods.
Larry Beuchat, a Distinguished Professor Emeritus and researcher in UGA’s College of Agricultural and Environmental Sciences, led a study to see just how long bacteria that cause foodborne illness can survive in certain foods.
“There have been an increased number of outbreaks of diseases associated with consumption of contaminated dry foods. We wouldn’t expect salmonella to grow in foods that have a very dry environment,” said Beuchat, who works with the Center for Food Safety on the UGA campus in Griffin.
Beuchat and study co-author David Mann, a research professional at the center, found that not only can harmful bacteria survive in dry foods, like cookie and cracker sandwiches, but they also can live for long periods of time.
For the recent study, published in the Journal of Food Protection, researchers used five different serotypes of salmonella that had been isolated from foods involved in previous foodborne outbreaks.
“Isolates were from foods with very low moisture content,” Beuchat said.
Focusing on cookie and cracker sandwiches, the researchers put the salmonella into four types of fillings found in cookies or crackers and placed them into storage. The researchers used cheese and peanut butter fillings for the cracker sandwiches and chocolate and vanilla fillings for the cookie sandwiches—the kind found in grocery stores or vending machines.
After storing, the UGA scientists determined how long salmonella was able to survive in each filling. There was survival in all types, Beuchat said, but salmonella survived longer in some types of the fillings more so than in others.
“The salmonella didn’t survive as well in the cracker sandwiches as it did in the cookie sandwiches,” Beuchat said.
In some cases, the pathogen was able to survive for at least six months in the sandwiches.
“That was not expected,” he said.