Contamination of pasteurized milk by Bacillus cereus in the filling machine

The contamination of pasteurized milk by Bacillus; cereus during the fillin g process Was studied in two dairy plants. Samples of pasteurized milk Were taken at four different sites along the production line. The samples were stored at 7 degreesC for 7 d or at 10 degreesC for 5 d, before plate counti ng and random selection of B. cereus isolates. Isolates of B. cereus were t yped by the polymerase chain reaction (PCR)-based method randomly amplified polymorphic DNA (RAPD). Samples taken at three different sites between the pasteurizer and the filling machine Were all holding similar low concentra tions of B. cereus, while an increase of the B. cereus count vas seen in th e consumer packages. More B. cereus of different RAPD types was growing in the consumer packages than in samples, taken just before the filling machin e. Several RAPD types found in the consumer packages were not detected in t he samples taken just before the filling machine.