566 



STATE BOARD OF AGRICULT-URE. 



Table IV 

 Weekly weighing sheet showing bonus system. 



Note: All milk weighed in bold figures are grade B. and receive no bonus. 

 bonus as grade A milk. 



Remainder receive 



This sheet is kept on the weighing floor and is a guide to the weigher in 

 dumping milk. Milk is dumped into the Grade A or grade B tank depend- 

 ing upon the score for the previous day. The laboratory man after making 

 daily tests records score upon sheet and places a bracket around weights of 

 samples of grade B milk. If samples are not taken daily the patrons milk 

 will remain in the class of last test until a retest is made. 



By means of daily notification of the producer as to his score it is thought 

 that his interest and cooperation might be secured and an increasing per- 

 centage of the daily milk brought to a score above 75. 



MARKET MILK 



Under the heading Market Milk may be considered the milk which has 

 been delivered to the city milk plant and prepared for the market. Samples 

 for laboratory examination should be taken as the milk is delivered at the 

 home. The milk coming under this heading may be further classified as 

 raw milk, pasteurized milk, and special milk. 



Raw Market Milk. Raw market milk should be examined as to change 

 in pH as soon as possible after the samples have been brought to the labor- 

 atory. As rigid a standard for raw market milk may be imposed as is re- 

 quired for the milk plant supply. If the milk is properly cooled as soon 

 as received from the farm and is kept cool until delivered, the score by the 

 pH method will be as high as when received. This is due to the fact that 

 few of the bacteria will be able to develop in the cold milk and because some 

 of the active organisms, if not actually killed by the exposure to low tem- 

 peratures, have their growth inhibited to such an extent that the total activ- 

 ity of the bacteria present, when the milk is returned to a growing temper- 

 ature, may be less than before the cooling period. 



Pasteurized Milk. In examining pasteurized milk the "change in pH" 

 method may be applied in the same way that it is applied in examining raw 

 milk but the pasteurized sample should come up to a higher standard as 

 a number of the active acid producing bacteria have been destroyed during 

 the heating process. Efficiently pasteurized milk when stored at as low a 

 temperature as 7°C. will remain in good condition for several days as judged 

 by the pH test, but when held at a temperature of 21 °C. it will be unfit for 

 use in a short time. This is shown in Table V. 



