46 MAINE STATE COLLEGE 



THE EFFECT OF A DELAY IN SETTING MILK. 



It is often the case that milk is allowed to stand an hour or so 

 after it is drawn before it is strained and set in cold water. 

 Especially with a large herd, the milk of the first animals milked 

 may sit some time before it is brought into contact with the 

 cold water. Again, oftentimes the dairy-man is careless in 

 allowing the milk to stand unnecessarily and so does not strain it 

 into the cans nearly as soon as he might. The question arises, 

 What is the effect of this delay in setting milk upon the amount 

 of fat which is left in the skimmed milk ? In order to secure 

 information upon this point the matter was tested in the follow- 

 ing manner : The milk of several animals (grades) was drawn as 

 quickly as possible, thoroughly mixed in a large vessel, divided 

 into two equal parts and one-half immediately submerged in 

 water at a temperature of about 40°. The other half of the milk 

 was allowed to staud from one-half hour to an hour, after that 

 delay being submerged in the same cabinet with the other portion 



of the milk. 



The following data were recorded : 



The weight of milk set ; the temperature of that portion of the 

 milk which was placed in the cold water immediately ; the tem- 

 perature at the time of submerging of that portion of the milk 

 which was allowed to stand some time before placing in the 

 cold water ; the composition of the milk which was used in the 

 tests and the composition of the skimmed milk. 



The first test was made from Jan. 20th to Jan. 24th, 1890, 

 and the second test was made from Feb. 3rd to Feb. 7th, 1890. 

 In the case of the first test, that portion of the milk which was 

 allowed to stand some time before setting in the cold water was 

 strained into the cans at the same time that the other portion was 

 set in the water, and when finally placed in the water it was not 

 stirred. During the second test that portion of the milk which 

 was not put into cold water until after a half hour or an hour, 

 was thoroughly stirred at the time it was submerged. This latter 

 method of treatment would correspond entirely to the way in 

 which milk is manipulated when it is allowed to stand some time 

 before straining. It should be stated that the milk which was 

 not at once placed in the cold water was in the first test allowed 

 to stand in the dairy-room, and in the second test, in a cold walk 

 outside of the dairy-room. The results which are shown in the 

 tables below were a surprise. Their testimony, however, is un- 

 mistakably in one direction. 



