CHEESE. 223 



Wisconsin Dairy School in 1895. Apparatus for making 

 the test is now furnished by dairy supply-houses, although 

 a home-made test can be improvised by using pint fruit- 

 jars and a wash-tub or some small tank, in which the jars 

 of milk can be heated in warm water. 



Details of the Test. — i. A pint glass jar which has 

 been thoroughly cleaned, and sterilized with live steam, is 

 filled about two thirds full with the milk to be tested. 



2. It is not necessary to take an exact quantity of milk, 

 but each jar should be plainly labeled. 



3. The numbered jars of milk are placed in a tank or tub 

 of water which is heated until the milk in the jars has a 

 temperature of 98° F. 



4. The thermometer used should first be rinsed in boiling 

 water before being placed in another sample, to avoid con- 

 tamination of good milk with bad milk. 



5. When the milk has reached a temperature of 98° F., 

 add 10 drops of rennet extract to each jar of milk, and mix 

 by giving the jar a rotary motion. 



6. The rennet soon curdles the milk, and the curd is al- 

 lowed to stand for about twenty minutes until it is firm. 



7. The curd should then be cut into small pieces with a 

 case-knife, and after settling the whey is poured off. 

 The best tests are made when the separation of whey is 

 most complete. By allowing the samples to stand for a 

 short time, more whey can be poured off, and the curd 

 thereby rendered firmer. 



8. The jars containing the curd are then again placed in 

 the tub and the temperature of the water around the jars is 

 maintained at or near 98° F. by adding hot water from time 

 to time. The tub or vat is covered, the curds are allowed 

 to ferment in the sample jars for six to twelve hours and 

 are then examined. 



9. The impurities in any particular sample will cause 

 gases to be developed in the curd, so that when it is cut 

 with a knife pin-holes or gas-holes can be easily detected. 

 Milks having a putrefactive or stinking odor should be 

 classed as bad, even though the curd has a good texture 

 and is free from pin-holes. 



