NUMBER AND SOURCE OF BACTERIA IN MILK 255 



in others as high as 1,048,000, the variation being due 

 to differences in the season at which the samples were 

 taken, the cleanliness of the cows, the method of milking, 

 and other factors. 



With reasonable care it should be possible at most of 

 the farms in this country to produce milk containing not 

 more than about 10,000 to 20,000 bacteria per c.c. when 

 it leaves the farm premises ; samples taken at the farm 

 and found to contain more than 50,000 per c.c. should 

 be considered as unnecessarily dirty and indicating 

 negligence and disregard of precautions against con- 

 tamination. 



In addition to the pollution of milk which takes place 

 at the farm, there is additional contamination during 

 transit to the consumer. Bacteria are added during the 

 railway journey, at the retailer's premises, on the milk- 

 man's rounds, and, finally, at the consumer's house. 



Very many of the milk churns sent by rail are faulty 

 in design, the lids allowing of easy access of dust 

 and rain into the interior. The vans in which they 

 travel are often dirty, and no special care is taken to 

 unload or store the churns at properly cleaned depots, 

 away from dust, foul odours, and other damaging 

 influences. 



When the churns are opened at the railway termini 

 and small amounts transferred by means of imperfectly 

 cleaned ladles or measures to the dairyman's cart, con- 

 tamination occurs ; the same happens when the milk 

 is poured over the rims of churns on which dust has 

 collected or which have been handled by workmen whose 

 personal cleanliness is not of the highest order. 



Hewlett and Barton found from 20,000 to 8,390,000 

 bacteria 'per c.c. in milk samples taken at various railway 



