MARKET MILK AND CREAM 121 



ment Station at Guelph. The excuse sometimes 

 offered in court that milk has lost its cream while 

 being sold is not valid, as all the experimental evi- 

 dence shows that when milk is dipped from the can 

 with a long-handled dipper no separation of the fat 

 takes place. While milk changes in its per cent of 

 solid matter but little during transportation, it often 

 becomes sour and foul through unnecessary exposure 

 and unclean ways of handling. 



111. Pasteurizing Milk and Cream. In order to 

 prevent milk and cream from readily fermenting, it 

 is sometimes given the Pasteurizing treatment. This 

 consists of heating the milk or cream to a tempera- 

 ture of 159 or 160 F. for a few minutes and then 

 cooling and protecting it from further inoculations. 

 This temperature results in rendering inactive the 

 greater number of ferments in milk, particularly 

 those of an objectionable nature. The destruction 

 of the ferment bodies prevents rapid souring of the 

 milk, especially when the milk is protected from 

 further contamination. The Pasteurizing of milk 

 and cream is usually done by machinery, the milk 

 being agitated so as to secure as even an application 

 of temperature as possible. The longer the milk is 

 heated, the more thorough is the Pasteurizing pro- 

 cess. Not all of the germs or ferments of milk are 

 rendered inactive by heating to a temperature of 

 160. To render inactive the tuberculous bacilli, a 

 temperature of 180 to 185 is required. When milk 

 is sterilized, it is heated to a higher degree than 



