MILK STANDARDS . 311 



dirt per million of milk, would be a generous standard, 

 and one which would not entail unnecessary and burden- 

 some attention to cleanliness on the part of the farmer. 



(ii) Number of bacteria and temperature standard. 

 -Milk produced under clean conditions, if cooled to 

 10 C. or lower as soon as possible after it leaves the 

 cowshed, and maintained at that temperature, need not 

 contain more than 10,000 or 12,000 bacteria per c.c. in 

 summer, or half this number in winter ; some dairies are 

 able to supply milk of this quality to their customers all 

 the year round. 



Park suggested that milk containing more than 

 100,000 per c.c. should not be sold for domestic use, 

 but this standard is easily exceeded in districts where 

 ice or other means of refrigeration are not available, 

 especially in the warmer seasons of the year. 



In Boston the standard of 500,000 per c.c. is enforced 

 upon retailers, and milk for sale must be stored at tem- 

 peratures not higher than 10 C. 



In this country the number of bacteria in samples 

 taken at the cowshed should not exceed 50,000 per c.c. 

 Milk taken at the railway termini of large towns does not 

 usually contain more than 500,000 per c.c., unless the 

 weather is very warm, and the railway journey has been 

 prolonged in exposed vans and waggons. 



(iii) Acidity. Milk which has not been kept cool, 

 or which has been stored in unclean vessels in dirty 

 shops, especially if obtained from a badly kept farm, 

 soon becomes acid and more or less toxic from the 

 action of " coliform " organisms in it. 



Newman proposed that no milk should be sold 100 

 c.c. of which required for neutralization more than 22 

 c.c. of a deci-normal solution of caustic soda. 



