70 PRINCIPLES AND PRACTICE OF MILK HYGIENE 



into long strings with a rod or stick. The bacteria which 

 cause this defect are frequently introduced into the milk 

 by the water used to wash the milk vessels and utensils. 

 Milk-houses, storage tanks, etc., may be infected by the 

 same means. Water from streams and shallow wells 

 receiving surface drainage, also from springs receiving 

 surface or subsurface drainage, is especially likely to 

 contain the organisms. They are also to be found on 

 vegetation growing in low, damp places and on straw 

 stored in a damp condition. In Sweden " stringy " milk 

 is prepared artificially and is a popular article of food 

 (tatmjolk), while, in Holland, Edam cheese is made 

 from " stringy " milk produced by a certain organism. 



3. fc Soapy " Taste. Milk may acquire a " soapy " 

 taste from the action of bacteria which attack the proteids 

 and fat of milk. Several species of these organisms have 

 been found on straw and fodder. 



4. Failure to Sour and "Butter" Milk may not 

 sour and cream may not sour and " butter " at all or only 

 very slowly. This defect may be due to a deficiency in 

 acid-forming bacteria or to an excess of peptonizers. In 

 the latter case, the milk or cream usually has a bitter 

 taste ; occasionally a " soapy " taste. Alkali-forming bac- 

 teria, butyric acid bacteria, some of the organisms of the 

 coli-aerogenes group and certain yeasts and fungi may 

 also delay or prevent souring and " buttering." In some 

 cases the cream foams when churned, in consequence of 

 the formation of gas. This defect is especially liable to 

 occur when cows are pastured on low, wet land; also when 

 the leaves of roots (beets, etc.) , are fed, and in cold, wet 

 weather. Cream from the milk of cows near the end of 

 lactation will not " butter " sometimes because of the 

 alkalinity of the secretion. 



