476 



FARMER'S CYCLOPEDIA OF LIVE STOCK 



per cent. This loss in the milk flow may 

 be avoided by dehorning calves while 

 young. 



Contamination of milk with dirt and 

 bacteria — Mention has already been 

 made of certain rules by which sanitary 

 milk may be obtained. It seems desir- 

 able to call further attention to the 

 ways in which milk may become con- 

 taminated. Fraser, in Illinois, found 

 that the amount of dirt which falls from 

 the udder in milking varies according to 

 the character of the dirt, the amount of 

 hair on the udder, its shape and the 

 length of teats. In these tests three and 

 one-half times as much dirt fell from 

 unwashed udders as the same udders 

 after they had been washed; while in 

 some cases where the udders were muddy, 



Fig. 305— RACK FOR MILK CANS 



nine times as much dirt fell from the 

 udder before washing as after washing. 

 With udders in average condition it was 

 found that an ounce of dirt would fall 

 from each udder in the course of thirty- 

 two milkings or 1 ounce of filth. for each 

 275 pounds of milk. After washing, how- 

 ever, there was only 1 ounce of filth in 

 each 24,000 pounds of milk. 



All dirt on cows' udders and on the 

 milker contain bacteria; consequently 

 the number of bacteria which gain en- 

 trance to the milk varies with the 

 amount of filth. 



Washing dairy utensils — It is too 

 often the case that the dairyman is sat- 

 isfied with cleaning milk utensils like 

 kitchen dishes. More care is required 

 in cleaning dairy utensils, for the reason 

 that bacteria multiply so readily in the 

 smallest particles of milk which may be 

 left in the corners of dairy utensils. Erf 

 and others have repeatedly called atten- 

 tion to the necessity of using a brush, 

 and a good washing powder on every 



part of the cream separator after each 

 using. All parts should then be rinsed 

 in boiling water, or, still better, steamed 

 and left to dry while hot. The use of 

 wiping cloths is almost sure to contami- 

 nate milk utensils, since they are not 

 bacteriologically clean, except in the 

 rarest instances. Erf found that the 

 bacterial contamination of milk was in- 

 creased three times by running it 

 through a separator which had merely 

 been flushed and not thoroughly cleansed. 

 Various investigators have found that 

 the separator slime, found in the separa- 

 tor after the cream has been removed, 

 contains a relatively large percentage 

 of bacteria, and whenever this is used 

 in feeding pigs, without previous boil- 

 ing, tuberculosis develops in a large 

 percentage of cases. 



Haecker and others have found it de- 

 sirable to use special precautions to 

 prevent the contamination of milk dur- 

 ing milking. It is recommended by 

 Haecker that the udder and teats be 

 washed, after which an application of 

 a vaseline ointment containing 5 per 

 cent of carbolic acid is used. 



Fermentation of milk — The presence 

 of bacteria or other filth in milk leads 

 to rapid fermentation and souring. It 

 is a comparatively simple matter to 

 convince one's self that the exercise of 

 special care in preventing the contam- 

 ination of milk will yield milk which 

 will keep much longer than that which 

 has been carelessly handled, and, there- 

 fore, contains filth. This is a matter of 

 great importance to the dairyman who 

 sells milk for use as such, since the cus- 

 tomer naturally wants milk which will 

 keep fresh as long as possible. If milk 

 is intended for the manufacture of but- 

 ter or cheese, harmless bacteria in it 

 simply serve to hasten the ripening proc- 

 ess. Some of these bacteria, however, 

 may give a rancid or otherwise disagree- 

 able flavor to the butter or cheese. Even 

 when every possible precaution is taken, 

 enough bacteria will gain entrance to 

 the milk to produce a souring and ripen- 

 ing of the cream. 



More than 200 species of bacteria 

 have been found in milk. Fortunately, 

 however, most of them are harmless, ex- 

 cept that they cause the milk to sour. 

 Some produce bitter flavors, others, gas, 

 and still others, color changes. The best 

 results in the souring of milk and ripen- 

 ing of cream are obtained when bac- 

 teria are excluded as far as possible by 



