10 A Handbook for Dairymen 



If the temperature in the incubator is too low, 

 the growth of the organism will be very slow, or it 

 will not grow at all. Also if the temperature is too 

 high, the organism may not grow. In either case 

 if it does grow, it will not give a strong type and 

 contaminations are likely to appear. 



Starter. 



A practical application of bacteriology to dairy 

 operations is the preparation of starter.* The 

 lactic acid starter used in the making of butter and 

 cheese is the most common. Other starters are the 

 molds of Camembert and Roquefort cheese, Bulgari- 

 cus for Swiss cheese, the eye-forming culture for 

 Swiss cheese, and the starter for ripening cream for 

 Hebrew trade. 



The Lactic Acid Starter. 



Since cultures must be prepared by a bacteriolo- 

 gist, commercial laboratories have developed a large 

 business in their production, usually under trade- 

 marked names. Some of these cultures represent 

 races of lactic bacteria cultivated and cared for 

 efficiently, hence uniformly valuable over long 

 periods of time. Others, carelessly produced, are 

 worthless, or even a peril to the user. 



The organisms are usually shipped in small 

 quantities in bottles of liquid or powder, or in cap- 

 sules of uniform size. The contents may be either 

 the culture medium upon which the organisms grew, 

 or an inert substance designed merely to hold the 

 bacteria in active form. In either solid or liquid 

 form, the producer of the culture should guarantee 

 its activity up to a plainly stated date. 



* Starter is a culture of desired organisms in a living or active 

 state. 



