EXPERIMENT STATION BULLETINS. 261 



jfcoring tests which take in cheese from all parts of the state, by far the most 

 common fault was that caused by gas germs. These germs impart a very strong 

 and undesirable flavor and besides make the cheese full of holes, openings about 

 the size of a pinhead, hence the common name "pinholey." Such cheese tends to 

 become dry and coi'ky, a condition which, combined with the peculiar flavor and 

 texture, renders the cheese practically worthless. 



A good way of fighting this evil brought about by the gas germs in milk is to 

 use a fine flavored sour milk, usually called a starter, using about four pounds of it 

 to a hundred pounds of the infected milk. Gas germs cannot live and grow in 

 the presence of overwhelming numbers of acid germs. On the other hand the acid 

 i^erms cannot grow rapidly in the presence of large numbers of gis germs. This 

 is why it is so difficult to develop acid in gassy curd. If the milk is excessively 

 ^■assy the following treatment is suggested: 



Use about four pounds of starter for 100 pounds of milk; develop a little more 

 than the usual amount of acid before setting; cut fine and heat quickly to 100° 

 or above if necessary. Remove whey when the curd shows one-fourth inch acid; 

 place curd upon the racks and allow it to mat thoroughly by frequent turning 

 and deep piling, keeping the temperature constantly at 98°. Cut the curd and 

 air thoroughly by frequent stirring until gas holes flatten out and the gassy 

 flavor disappears. This rnay require from two to four hours. Wash curd with 

 clean warm water before salting. The following pointers on starters are sub- 

 mitted here as of value in this connection: 



A good starter is a clean flavored batch of sour milk or skim cream. 



Starters are used to overcome bad fermeutation in milk and cream. 



There are two kinds of starters: (1) natural; (2) commercial. 



A natural starter is ordinary sour milk or skim milk. 



Commercial starters are made in laboratories by selecting and breeding the 

 right kind of germs. 



Commercial starters are giving very good satisfaction and their use is rapidly 

 increasing. 



Among the important of these starters or cultures may be mentioned: 



1. Douglas Culture, manufactured by O. Douglas, Boston, Mass. 



2. Keith Culture, manufactured by S. C. Keith, Jr., Charlestown, Mass. 



3. Hansen's Culture, manufactured by Hansen's Laboratory, Little Falls, N. Y. 

 Commercial starters are prepared as follows: 



Heat four pounds of milk, or preferably skim milk, to 160° F. Keep at this 

 temperature 10 to 15 minutes, then cool quickly to 70° F. Now introduce bottle 

 of Commercial Culture and let stand till milk has just thickened. This thickened 

 milk is the starter. 



The starter is carried on from day to day as follows: 



Heat and cool milk as explained above (pasteurize) and introduce into it 

 enough of the four pounds of starter already made to sour the milk in 24 hours 

 at a temperature of 70° F. The amount required is generally 3 to 4 per cent; that 

 is to every 100 pounds of pasteurized milk we must add 3 to 4 pounds of old or 

 mother starter. The remainder of the old starter is added to the milk used for 

 cheese making. 



By always saving a little of the old starter and putting it into milk newly 

 pasteurized (heated and cooled) the original ferment can be carried from one 

 batch of milk to another for weeks. 



