22 BULLETIN 356, U. S. DEPARTMENT OF AGEICULTUBE. 



milk and escape the observation of tlie producer. Bits of straw or 

 hay an inch or an inch and a haK long have been found in the bottom 

 of the bottle, and cow hairs are often found in the sediment, and 

 occasionally bristles from brushes 



To avoid visible dirt in the milk and thus receive a high score on 

 this point it is necessary to follow the rules for cleanliness laid down 

 under the heading "Bacteria." Sometimes the sediment is due to 

 the fact that pails or bottles after being sterilized are allowed to 

 stand uncovered. If there is any wind stirring, chaff, dust, etc., are 

 almost sure to be blown into the pails or bottles and will thus appear 

 as sediment in the milk. Coarse strainers should be avoided if the 

 producer wishes to get all the fine dirt out of the milk. The best 

 results in the past have probably been secured with the use of cotton 

 as a straining medium. Various forms of cotton are on the market, 

 some in bulk and some prepared in thin sheets especially for strain- 

 ing. In the answers to questions on the production of milk for con- 

 tests there does not seem to be any special advantage in milking 

 on to a strainer over the milk pail. Unless the strainer cloth is 

 changed when each cow is milked such a practice is liable to residt 

 in worse contamination than when the milk is simply milked into an 

 open pail and then strained into the can. 



TAT AND SOLIDS NOT FAT. 



Except in occasional cases a normal milk having a fat content of 

 4 per cent contains more than 8.7 per cent of solids not fat. In some 

 contests several samples have been entered which apparently had 

 been modified by the producer in the attempt to obtain a higher score 

 on chemical composition. Milks testing 8 per cent of fat and over 

 have been submitted. Fortunately, such an adulteration is very 

 easily seen by the judges when the fat is compared with the sohds 

 not fat. The contestant who tries to improve upon nature in this 

 manner often decreases, rather than increases, his score. Any milk 

 containing as much as 4 per cent of fat receives a perfect score, so 

 that an 8 per cent milk gets no higher score on fat than a 4 per cent 

 milk. The result of adding cream to milk to bring it from a 4 per 

 cent to an 8 per cent fat is to lower the proportion of solids not fat 

 in the milk, so that the score on that item is sometimes cut consider- 

 ably. In normal milk the solids not fat increase as the fat increases 

 but not in the same ratio. In milk to which cream has been added, 

 however, the fat increases and the solids not fat are decreased. 



To eliminate contact with aU unnecessary utensils some contest- 

 ants have milked directly into the milk bottle. The first part of the 

 milk drawn from the cow is quite deficient in fat, while the very last 

 of the milk runs high in that constituent. In order to have a normal 



