Location: Food Science Research
2009 Annual Report
The safety of acidified foods is of concern to FDA and producers of these products. Some disease causing bacteria are very acid resistant and can survive for up to several months in some acidified foods such as cucumber pickle products, if these foods are not properly treated. Bacterial strains of a common acid resistant organism Escherichia coli O157:H7 were analyzed to determine how they survive under conditions of acidified foods. It was found that survival and acid resistance varied depending on source of isolation of the strain. Strains isolated directly from animal sources were more acid resistant than strains isolated from foods or human disease.
Cooperative research to determine how bacterial strains alter acid resistance with continuous growth on laboratory media were carried out. Disease causing bacteria isolated from foods, animal manure, water and other sources (Escherichia coli O157:H7) were previously found to vary in acid resistance depending on the source of isolation for the strains. Bacterial strains were used that were previously sent to Kangwon University, South Korea, for collaborative research. It was found that the variation in acid resistance of these strains was not due to repeated growth on laboratory media.
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