DAIRYING 83 



No less than 158 degrees for at least 3 minutes. 

 No less than 155 degrees for at least 5 minutes. 

 No less than 152 degrees for at least 10 minutes. 

 No less than 148 degrees for at least 15 minutes. 

 No less than 145 degrees for at least 18 minutes. 

 No less than 140 degrees for at least 20 minutes. 



STANDARDIZING MILK AND CREAM. 



809. When milk and cream are sold directly to the consumer 

 either in bottles or in any other way, a uniform richness in these 

 products from day to day is very much desired. Such uniformity 

 is not only a recommendation to the buyer, but it is more profit- 

 able to the dealer to standardize each lot of milk and cream to a 

 certain per cent fat than it is to have no definite knowledge of 

 their richness and run the risk of losses through variations in the 

 per cent of fat. 



Many ways have been suggested for reducing the figuring 

 necessary to determine how many pounds of milk and cream of a 

 given richness must be taken in order to get a mixture of a certain 

 per cent fat. 



Tables of figures have been published and short formulas given 

 for making such calculations but one of the most common methods 

 of calculation recommended is the following : 



810. Place at the left hand corners of a square the tests of 

 the two kinds of milk or cream that will be used for making the 

 standard product. In the center of the square place the test of 

 the milk or cream wanted, then subtract diagonally, placing at 

 the right hand corners of the square the differences between the 

 figure in the center of the square and the figures thus obtained. 



liese latter figures at the right hand corners represent the pro- 

 >rtions in which the milk and cream should be mixed. 



811. Standardizing milk. If milk testing 3.0% fat is wanted 

 id two lots of milk, one testing 2.5% and the other 4% fat are 



available, the proportions in which these two should be mixed 

 may be found as follows. See directions given above. 



