DISCRIMINATION OF PSYCHROTROPHIC AND MESOPHILIC STRAINS OF THE BACILLUS-CEREUS GROUP BY PCR TARGETING OF MAJOR COLD SHOCK PROTEIN GENES

Detection of psychrotrophic strains (those able to grow at or below 7 degrees C) of the Bacillus cereus group (Bacillus cereus, Bacillus thu ringiensis, and Bacillus mycoides) in food products is at present extr emely slow with conventional microbiology. This is due to an inability to discriminate these cold-adapted strains from their mesophilic coun terparts (those able to grow only above 7 degrees C) by means other th an growth at low temperature, which takes 5 to 10 days for detection. Here we report the development of a single PCR assay that, using major cold shock protein-specific primers and appropriate annealing tempera tures, is capable of both rapidly identifying bacteria of the B, cereu s group and discriminating between psychrotrophic and mesophilic strai ns. It is intended that this development help to more accurately predi ct the shelf life of refrigerated pasteurized food and dairy products and to reduce the incidence of food poisoning by psychrotrophic strain s of the B, cereus group.