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. “ 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. 
