Contamination of Milk. 27 



fluctuations; but, nevertheless, such determinations are of 

 value as giving a scientific foundation for practical meth- 

 ods of improvement. The following studies may serve to 

 indicate the relative importance of the utensils as a factor 

 in milk contamination. 



Two cans were taken, one of which had been cleaned in 

 the ordinary way, while the other was sterilized by steam- 

 ing. Before, milking, the udder was thoroughly cleaned 

 and special precautions taken to avoid raising of dust; the 

 fore milk was rejected. Milk drawn into these two cans 

 showed the following germ content: 



No. bacteria Hours before 

 per cc. souring. 



Steamed pail 165 28 



Ordinary pail 4265 23 



Harrison 1 showed the great variation in the bacterial 

 content in milk cans in the following way: Cans were 

 rinsed with 100 cc. of sterile water and numerical deter- 

 minations of this rinsing water made. The following data 

 are from cans poorly cleaned (Series A), cans washed in 

 tepid water and then scalded the usual factory method 

 (Series B), and cans washed in tepid water and steamed for 

 five minutes (Series C). 



Bacterial contents of cans cleaned in various ways. 



Series A, dirty cans 238,525 342,875 215,400 618,200 806,320 



510,270 230,100 610,510 418,810 317,250 



Series B, ordinary method 89,320 84,750 26,800 24,000 38,400 



76,800 15,200 13,080 44,160 93,400 



Series C, approved method 1,170 1,792 890 355 416 



A variation of this method was made by the writer as 

 follows: Three pails were thoroughly washed with 100 cc. 



Harrison, 22 Kept. Out. Agr'l Coll., 1896, p. 113. 



