248 Bulletin 38. 



milk was sweet and became profanely abusive when the weigher 

 politely told him that milk in that condition would thereafter 

 be refused. Other lots of milk with a temperature as low as 84 

 degrees were sour, indicating that lack of cleanliness had contrib- 

 uted to their souring. 



As stated before, this condition of affairs is absolutely unnec- 

 essary. In our experience at the Experiment Station farm we 

 have observed that by the use of the ordinary tin-drum milk- 

 cooler filled with well water, which with us has a temperature of 

 from 70 to 73 degrees, milk may be reduced in temperature ten 

 degrees; that by running it over the cooler a second time the tem- 

 perature may be brought down five degrees more; and that by 

 wrapping the cans in which the milk stands over night in wet 

 burlap or gunny sacks the temperature may be still further re- 

 duced to that of the atmosphere or lower. During the first fif- 

 teen days in July, including the hottest days and nights of the 

 season and the hottest twenty-four hour period recorded since the 

 establishment of the weather bureau in Phoenix, the average 

 temperature of the night's milk in the morning, under this treat- 

 ment, was 71 degrees, which was less than the average minimum 

 temperature of the atmosphere for that period. On very warm 

 nights the temperature of the milk went several degrees below 

 that of the surrounding air. Under this treatment the increase 

 of acid in the milk during the night was very slight. The aver- 

 age per cent of acid in the milk immediately after milking, dur- 

 ing the first ten days after July, was. 165 per cent, while the 

 same milk on the following morning showed a presence of only 

 . 17 per cent of acid. Milk seldom smells or tastes sour when 

 containing less than .3 per cent of acid. 



With these facts to base conclusions upon we feel safe in 

 stating that, with the exercise of reasonable cleanliness in milk- 

 ing and in the care of utensils, and by taking proper care in cool- 

 ing, milk may be delivered at the factory in good condition, and 

 that there is no excuse based on reason for what we deem the 

 criminal adulteration of milk by the use of chemical preservatives. 



Gordon H. True, 



Department of Animal Husbandry. 



