58 DAIRY ANALYSIS 



more than 25 c.c. capacity, and keep for half an hour 

 at a temperature of 37 C. (blood heat) ; if the colour 

 disappears, the milk is not fresh. 



Milk which is not fresh gives a high catalase figure, 



. 30. Using Microscope. 



but this is not conclusive evidence, as high catalase 

 figures are obtained with fresh milk from cows with 

 diseased udders. 



Custards made with eggs, especially if much sugar is 

 added, inevitably curdle if heated to too high a tem- 

 perature ; the liquids from such samples are usually high 



