MILK DEFECTS 71 
5. Stable-like, turnip-like, and beet-like tastes, and a 
burnt or malt-like taste and odor are each caused by cer- 
tain species of bacteria. 
6. Blue Milk.—The Bacillus cyanogenus, also called 
the Bacterium syncyaneum, produces a grayish color on 
the surface of milk and, when the milk is sour, blue spots, 
which may become confluent. There are several other 
species of bacteria which produce a blue color in milk. 
7. Red Milk.—Red spots or a diffuse red color on the 
surface are produced by the Bacillus prodigiosus, also by 
Sarcina rosacea and several other species of organisms. 
The Bacterium lactis erythrogenis curdles milk, then 
dissolves the curd and colors the fluid diffusely red. 
8. Yellow- or orange-colored spots are produced 
usually by the Bacillus synxanthus; also by the Sarcina 
lutea, Sarcina flava and the Bacterium fuloum. 
9. A yellowish-green discoloration is produced by the 
Bacillus pyocyaneus. 
10. Greenish-yellow spots and diffuse discoloration 
may occur in sour milk as a result of the growth of the 
Bacillus fluorescens. 
11. Violet-colored spots are produced by the Bacillus 
violaceus, Bacterium janthinum, Bacillus lividus and 
Bacterium amethystinus. 
In some cases, although very rarely, these pigment- 
forming bacteria are present in the udder. Usually, they 
enter the milk after it is drawn from the udder. They 
can generally be excluded by sterilizing the milk vessels 
and cleaning and disinfecting the places where the milk 
is stored; sunning it also if possible. Sometimes it will 
also be necessary to clean and disinfect the stable and to 
see that the cows are thoroughly cleaned before milking. 
