1902-3] Bacterial Contamination of Milk. 



491 



Much benefit would ensue either from moistening the fodder or 

 from feeding and bedding an hour or so before milking commences, to 

 allow the dust, etc., of the air time to settle. In many of the more 

 modern dairy farms, the stables are thoroughly cleaned and ventilated, 

 the floors sprinkled, and the manure removed from the building before 

 milking commences, or a milking room is provided, into which the cow^s, 

 one, two or three at a time, are brought for milking. This room is 

 supplied with water, conveniently located, and kept in an absolutely 

 clean condition. 



Contamination of Milk from Dairy Utensils. 



Probably more trouble is caused to butter and cheese makers b\' the 

 use of dirty utensils than any other way. Every article that is brought 

 into contact with milk is at once infected with bacteria. When milk is 

 left in storage cans for some time, a tremendous number of microbes 

 develop, and a vast number of spores or latent forms of bacteria are 

 produced. In this way, vessels are infected, and the bacteria find 

 lodgment in all the cracks and crevices of pails, cans, dippers, strainers, 

 etc. Take any milk-can and run the point of a pen-knife along the 

 seam of the can, and you will find a stinking, cheesy mass, composed 

 very largely of bacteria, all ready to grow and re-produce when fresh 

 milk is poured in the can. Nothing is more difficult to clean than these 

 dairy utensils, with the facilities at hand on the average farm. Scalding 

 with hot water is often insufficient to kill the bacteria on the inner 

 surface of the can, and in the cracks and crevices which are usually 

 present. The following experiments will suffice to show the importance 

 of utensils as a factor in milk contamination. Thus Russell^^ took two 

 cans, one of ^vhich had been cleaned in the ordinary way, while the 

 other was sterilized by steaming. Before milking the udder of the cow 

 was thoroughly cleaned and special precautions taken to avoid the 

 raising of dust ; and the fore-milk was rejected. Milk drawn into these 

 cans showed the following germ-content : 



Number of Bacteria. Hours before Souring. 



Steamed pail 165 per c.c 28)4 



Ordinary pail 4,265 " 23 



The writer^^ has also shown the great differences in the bacterial 

 content of cans by a bacterial analysis of the can washings. Cans were 

 rinsed with 100 c.c. of sterile water, and numerical determination of this 

 rinsing water was made. 



