MILK 227 



acidity and pathogenic germs which lead to stomach derangements 

 and kindred troubles. (3) The customer can always depend upon 

 his milk coming from the same farm, the same herd of cows, sub- 

 jected to the same treatment, and having the same quality. The fat 

 content is guaranteed not to vary outside of narrow limits ; hence the 

 milk is always of good quality. (4) Cleanliness and cold are the 

 only preservatives used. (5) It is a safe food for infants and people 

 with delicate digestion. (6) It is the natural product of the cow, 

 and has not been subjected to any treatment which affects its diges- 

 tibility or changes its character. (7) It is reasonably free from 

 foreign odors and objectionable flavors. 



The Future of the Certified-Milk Industry. The production 

 and sale of certified milk will probably never amount to more than 

 a small fraction of the total milk consumed. It is believed, however, 

 that the demand for this class of milk will increase, not only for in- 

 fants and persons of delicate health, but for people who appreciate 

 a good product and want the best. There is over a score of cities at 

 the present time each of which is supplied with certified milk from 

 one or more dairies, and it is believed that most cities of a population 

 of 25,000 to 50,000 or more would support a certified-milk dairy if 

 the product were properly advertised and its merits generally known 

 to the public. Physicians assist greatly in the sale of certified milk, 

 and, as a number of them are usually members of the milk commis- 

 sions in the various cities, they are thoroughly acquainted with the 

 conditions under which the milk is produced and freely recommend 

 its use. (Dep. Agr. Bu. An. Ind. B. 104.) 



SYSTEMS OF SEPARATING MILK. 



Four systems of separation are in common use; the shallow pan, 

 deep setting, dilution, and centrifugal. 



The Shallow Pan. The setting of milk in pans or crocks, let- 

 ting the milk stand for from twelve to twenty-four hours, depending 

 upon the temperature, and then skimming the cream, is known as 

 the shallow-pan system. This is the oldest method of separating 

 cream from milk, and varies greatly in efficiency, depending very 

 largely on how quickly the milk is cooled after coming from the cow 

 and how low a temperature is secured during the creaming process. 

 As low as .4 per cent of butter fat left in the separated milk has been 

 secured with the shallow pan when the milk was cooled immediately 

 after being milked and kept at a low temperature during the cream- 

 ing process. On the other hand it is not unusual to leave as high as 

 1 per cent of butter fat in the skimmed milk when the milk is set 

 in a warm room. Probably .8 per cent is a fair estimate for the loss 

 when milk is separated in this way. 



Deep-Setting System. The separation most frequently found 

 in use, next to the shallow pan, is the deep-setting system. The es- 

 sentials of this system are cans six to eight inches in diameter and 

 about two feet long, which are placed in cold water. Often a trench 

 is dug in a spring house in which the water stands at the proper 

 height and is continually running through the trench. This is a 

 very effective and economical method, both as to labor and expense 



