232 BACTERIA IN MILK AND MILK PRODUCTS 



principles which might be practised all over England. Briefly, it 

 may be said that Mr Carson's system lays emphasis on five chief 

 points : 



1. The cows used are carefully selected for milking purposes, are 

 regularly inspected, and have all been tested with the tuberculin 

 test. Their feeding is also kept under strict control, no brewers' 

 grains being used. In summer the cows feed on grass, linseed oil 

 cake, and a small quantity of cotton cake and bran ; in winter they 

 have hay, mangolds, maize, germ meal, and linseed and cotton cake. 

 The farm is well kept, and maintained under strict sanitary control, 

 the health and cleanliness of the cows being the one thing aimed at. 



2. The cows are milked in the byre adjoining the sterilising 

 plant. Both cows and cowsheds are continually maintained in 

 cleanliness. The udders are cleansed before milking, and it is required 

 that milkers also shall be clean in person and management of 

 milking. 



3. Immediately after milking, the milk is removed into an 

 adjoining room, strained through a metal screen, and at once 

 separated by an ordinary Laval separator. This separation is 

 adopted for purposes of purification only. The milk and cream 

 are again mixed, and poured by means of a mechanical automatic 

 bottle-filler into bottles. 



4. The milk in bottles is then, within a few minutes of leaving 

 the udder, placed in the steriliser and maintained at 212 F. for 

 twenty minutes. The bottles have been previously sterilised at 

 220 F. for sixty minutes. 



5. After sterilisation the milk is cooled to 53 F., and kept at 

 that temperature till required for delivery. 



We have examined this milk chemically and bacteriologically, 

 and have found it to be of excellent quality. It is unquestionably 

 an advantage to have milk which is to be sterilised brought under 

 treatment at once, after milking. This cannot always be done, and 

 hence it is the custom of some dairy companies and institutions to 

 sterilise milk on its delivery. But it is of extreme importance to 

 avoid this if practicable. Whatever treatment milk receives, be it 

 refrigeration or sterilisation, such treatment should be applied 

 immediately after the milk is drawn from the udder. There are a 

 large number of appliances and different forms of apparatus now on 

 the market, having for their object the sterilisation of milk. Our 

 object has not been the recommendation of any apparatus or process, 

 but the principles underlying the efficient pasteurisation and ster- 

 ilisation of milk. 



The methods of pasteurisation are continually being modified 

 and improved, especially in Germany, Denmark, and America. 

 Most of the variations in apparatus may be classed under two 



