Studies of the Bacterial Content of Washed Milk Cans

Abstract

SUMMARY: Colony counts at 30° were greater than 10 times those at 37° in a high proportion of rinses of washed milk cans, the difference being most marked in those containing milk scale, where 58% of the colony counts at 30° exceeded 106/can. A high proportion of the microflora was composed of thermoduric bacteria. Of 895 cultures from the milk scale, 33% were micrococci, 28% corynebacteria, 22% streptococci, and 9% were Gram‐negative rods. Though aerobic sporing rods constituted only 5% of the microflora of the milk scale, they were present in large numbers and unsatisfactorily washed cans probably constitute one of the main sources of these organisms in milk.