334 MANUAL OF MILK PRODUCTS 



in the milk and curd. The curd may exhibit peculiar 

 characteristics. It is usually difficult to firm in the 

 whey. The acid appears to develop slowly at first, but 

 very fast from the time the whey is started till it is all 

 removed. After milling the curd will become "mushy" 

 if it is at all moist, and the whey running from the curd 

 may show less acid than it did before milling. The 

 curd is usually very slow to shrink up before salting. 

 In extreme cases the whey tank may boil as though 

 heated by fire. 

 Cause. 



(1) Yeasts. These enter the milk on hay dust and from leaves 



of trees. They grow and multiply most rapidly when 

 milk is kept at temperatures above 60 Fahr. 



(2) Returning sour or unpasteurized whey in milk cans aggra- 



vates the trouble. 

 How to prevent. 



(1) Milk should be kept free from dust, and should be cooled 



to at least 60 Fahr. as soon as milked. 



(2) Use a clean commercial starter. 



(3) The whey should be pasteurized and the tanks cleaned 



every day. 



(4) If the trouble is already present, the whey tank, all factory 



utensils and all patrons' milk cans and utensils should be 

 thoroughly cleaned and scalded. 

 Remedy. 



(1) Add the rennet early. 



(2) Heat curd in the whey a few degrees higher. 



(3) Draw off the whey with as little acid as is practical, but 



have the curd well firmed first. 



(4) Do not pile the curd high unless gas is present. 



(5) If gas is present, more acid must be developed at dipping, 



but the curd should be stirred dryer. 



(6) After milling, if the curd tends to become mushy, one-half 



the salt should be applied. When the curd is well 

 shrunken, apply the other half. 



J. GASSY CHEESE. 



Indicated by the presence of pin holes. They usually have a 

 bad flavor, are spongy, and the curd may float on the 

 whey in the early stage of manufacture. 

 Cause. 



(1) Gassy milk produced by bacteria which are carried in by 



dirt. 



(2) Gassy starters. 



