Fatty Acid Profiling for Assessment of Diarrheal‐Type Enterotoxin Producing and Nonproducing B acillus cereus Origin from Foods Getting into L ithuanian Market

Abstract The study was undertaken to compare intraspecific variation of fatty acid (FA) profiles of Bacillus cereus isolated from different foods in order to find out if these profiles could be used for assessment of diarrheal‐type enterotoxin producing and nonproducing strains. A total of 123 strains of presumptive B. cereus were isolated from ready‐to‐eat foods, dried milk products, and dry products of nonmilk origin and identified by pyrosequencing assay. About 29.3% of B. cereus isolates were found to be enterotoxic. Statistical hierarchical cluster analysis did not show relation among diarrheal‐type enterotoxin producing and nonproducing B. cereus based on FA profiles in individual isolates. The profiles of cellular FA in B. cereus depended on the food type; however, all isolates produced 10 common FAs. Production of common FA within diarrheal‐type enterotoxin producing and nonproducing B. cereus changed when B. cereus was cultivated on tryptic soy agar supplemented with various additives or in liquid medium. Practical Applications Foodborne pathogens are one of the major sources of infectious diseases in humans. The Ministry of Health of the Republic of Lithuania, while releasing the report on the morbidity of various diseases including diarrhea, did not emphasize cases related to B. cereus. The data collected in this study demonstrated the pathogenicity level of B. cereus found in food products getting into the Lithuanian market. The classical microbiological method for B. cereus confirmation is time consuming, and genetic identification is rather expensive. Therefore, it is appropriate to seek faster and cheaper methods for the identification of these bacteria. Studies on detailed FA produced in B. cereus strains could be used for the characterization of intrinsic features of B. cereus, while common butyric, myristic, palmitoleic, stearic, oleic and linoleic acids could be used as biological markers for differentiation of diarrheal‐type enterotoxin producing and nonproducing B. cereus origin from foods of different type.