132 GUIDE TO DAIRYING IN SOUTH AFRICA 



products in a wholesome condition without the aid 

 of injurious chemical substances which may easily be 

 added, but which destroy the flavour and purity of 

 the product. 



Among the different complications produced in 

 milk by bacteria are lactic ferments, blue milk, red 

 milk, yellow milk, bitter milk, stringy and soapy 

 milks. Some of these are seen in the milk almost 

 at once, others are not. The lactic bacteria get 

 to work at once, and while these are useful to the 

 creamery they must be controlled ; for, as has been 

 shown on another page of this work under the 

 heading "Milk Sugar," the lactic bacteria attack 

 the milk sugar and change it into simpler sugars, 

 such as grape and galactose, finally forming lactic 

 acid. This work may be interrupted by another 

 set of organisms which attack the grape sugar 

 formed by the lactic germs, converting it into an 

 alcoholic fermentation. The milk or cream, there- 

 fore, should be delivered to the creamery or dairy 

 as soon as possible after it is drawn from the cow, 

 for it is better to allow the dairyman to control the 

 work of the lactic bacteria for his own purposes. 



Ropy milk is a condition frequently found on 

 the farm. The milk does not become sour on 

 standing, but when it has been kept standing for 

 a couple of hours it becomes slimy and can be 

 drawn out in long threads and has a sweetish taste. 

 These " slimy " bacilli live in water, and when this 



