MILK DEFECTS 69 



nish an environment favorable to their development. 

 Measures for the correction of these defects must be 

 based upon the source of the organisms concerned. 



1. Bitter Milk. Several species of bacteria, yeasts 

 and fungi have been isolated at different times from bitter 

 milk. In some instances the organisms responsible for 

 the bitter taste were found in the udder. Milk may ac- 

 quire a bitter taste from the action of the organisms 

 belonging to the peptonizing and gas-forming groups of 

 the common milk bacteria. This is especially true of 

 heated milk, in which the spores of the soil bacteria (hay 

 and potato bacilli ) survive. The occurrence of a bitter 

 taste in milk is often associated with the feeding of cer- 

 tain substances, notably mouldy or decomposed fodder, 

 beet and turnip leaves, and raw potatoes ; also vetch, wild 

 mustard and other cruciferous plants, leek, dog-fennel, 

 tansy, etc. The use of mouldy or decomposed straw for 

 bedding is accompanied by the same effect. It is believed 

 that the bitter taste is caused by organisms which are 

 present on these substances and which enter the milk 

 after it is drawn from the udder, and it is recommended, 

 therefore, that these feeds be given after milking, except- 

 ing, of course, those which are mouldy or decomposed. 

 Another theory is that the taste is due to a bitter sub- 

 stance which is ingested with the food and eliminated 

 through the udder. If milk is stored in rusted vessels 

 until a certain degree of acidity develops, it acquires a 

 bitter, astringent taste, due to formation of iron lactate 

 or acetate. Milk may also have a bitter taste just before 

 parturition and near the end of lactation. 



2. Viscid, ec Ropy" or " Stringy, " Milk. The milk 

 is thick and viscid and when it is poured from one vessel 

 to another strings are formed ; it may also be drawn out 



