Milking- Machines 367 



number of bacteria in the hand-drawn milk was 11,712 

 per cubic centimeter. Similarly, when the tubes had 

 been boiled in a borax solution, the machine-drawn milk 

 contained 506 bacteria per cubic centimeter, and the 

 corresponding hand-drawn milk 1,090 per cubic centi- 

 meter. 



These interesting experiments show strikingly that 

 with the exercise of extreme care the milking-machines 

 may prove an adequate means for the production of 

 sanitary milk with good keeping quality. They demon- 

 strate no less strikingly that in the ordinary dairy, and, 

 for that matter, in the best of dairies, the milking- 

 machine may prove a detriment rather than an ad- 

 vantage to the production of high-grade milk. They 

 again emphasize the fact that the elimination of bacteria 

 from dairy utensils is a matter of some difficulty, calling 

 for patience and intelligence on the part of the dairyman. 



Milk-strainer. — The milk-strainer is often another 

 prolific source of bacteria in milk. Apart from the dust 

 particles that fall on the strainer from the air of the barn 

 or dairy room, the dirt that gains access to the milk 

 during milking may itself be retained by the strainer, 

 while the germs adhering to it are washed into the milk. 

 Grotenfelt states that by spreading soil on the strainer 

 cloth and filtering milk through it, he found that the 

 microorganisms originally present in the soil were washed 

 off the soil particles and carried down into the milk. 

 Similarly, hairs or particles of manure, carrying on their 

 surface large numbers of bacteria, would be rinsed free 

 of microorganisms by the milk poured upon them. The 

 germ content of the milk is thereby materially increased, 



