March, 1936] Maintenance of Grade A Milk 13 



The lack of a sufficient amount of boiling water and not allowing suffi- 

 cient time to elapse for each piece of equipment to become thoroughly ster- 

 ilized were recognized as the most common errors. As a typical case, high 

 counts usually followed where one teakettle of boiling water was poured 

 through the strainer into the pail, given a couple of whirls and emptied into 

 the sink or into the other pails if there happened to be any. The whole opera- 

 tion seldom required more than a few seconds per piece of equipment. Also 

 the water cooled down rapidly from the boiling point as it was emptied from 

 one pail to the other. Even though the equipment had been carefully washed 

 and the tin was scoured bright, it would not be sterilized sufficiently under 

 these conditions to prevent serious bacterial growth and loss of Grade A 

 premiums. Frequently where a milking machine was used, those in charge 

 of the sterilizing were afraid of spoiling the rubber. However, the older the 

 rubber, the more porous it becomes and the more likely it is to cause high 

 counts. The dairymen using milking machines and having low counts not 

 only did a thorough job of sterilizing but they planned on replacing the rub- 

 ber parts coming into contact with the milk, at least every three months. 



One man used a commercial chemical solution for sterilizing his pails 

 and strainer and had very satisfactory results as long as he kept his equip- 

 ment thoroughly washed and scoured. His troubles began just as soon as he 

 permitted milk stone to collect in the pails. The chemical solution would not 

 penetrate through the milk stone and kill the bacteria as would the heat from 

 either boiling water or steam ; consequently counts developed running into 

 the hundreds of thousands. 



The most successful Grade A producers put each piece of equipment 

 into a tight-covered wash boiler or sterilizer which contained about two 

 inches of water. The equipment was then boiled and steamed in this nearly 

 air-tight container for at least three minutes after each milking. In using 

 this type of sterilizer on the milking machine, the pails and the rubber, tubes 

 and teat cups, one of large size was required and a wire rack was used so 

 that the rubber did not come in contact with the bottom and thereby become 

 overheated. , 



Milk cooling problems caused trouble for one-fifth of the producers with 

 bacteria counts over 25,000, mostly from May to October. The fact that 

 more cooling troubles were reported for September (as in sterilizing) than 

 any other month reflected the general tendency to be short of ice at the end 

 of the summer. The principal factor in the cooling problem was that the 

 milk was not cooled below 50° F. soon after milking ; especially the cooling 

 of the milk after it reached 60° F. was too slow. Among the items that 

 brought about this condition were : tank too small, lack of ice in tank, and 

 ice put in tank at milking time instead of keeping tank iced between milking 

 periods. The last of these conditions was found where non-insulated tanks 

 were used. Those using insulated tanks had ice in the water continually, and 

 often a piece of ice would not be entirely melted in three days' time, which 

 meant that the temperature of the water was 37° F. or lower. Some did not 

 strain the milk after milking each cow because it was too far to the milk 

 house. Others set the can just outside the barn during milking instead of 

 following the approved practice of putting the can into ice water and cooling 

 the milk as soon as possible so as to stop bacterial growth. One producer 

 found it necessary to rebuild his tank so as to raise the water level higher 

 on the necks of the cans. He installed a new cork-insulated tank which re- 

 quired less ice and also corrected the trouble. In general, those who had 



