620 MILK 



thirty hours, it is cut into 2-inch squares and stirred with a spoon. 

 The vessel containing the clabber is placed in hot water and kept 

 at 100° F. for thirty minutes, with an occasional stirring apphed. 

 The curd and whey are then poured into a cheesecloth bag and 

 hung so that the whey is strained off. The curd is worked toward 

 the center of the bag with a spoon. The cheese is finally removed, 

 a teaspoonful of salt per pound added, and cream mixed with it 

 to suit the taste. Cottage cheese can also be made by using sweet 

 skimmed milk with addition of rennet. Rennet cheese has a 

 finer texture than sour milk cheese, is made in a shorter time, 

 and less curd is lost in the process. Dahlberg recommends the 

 use of pasteurized milk for making cottage cheese. 



Buttermilk cheese is made by coagulating buttermilk with 

 heat. Sammis states that buttermilk cheese is superior in text- 

 ure and flavor to cottage cheese, and can be sold with profit 

 for half the price. Its food value is equal to that of lean beef- 

 steak. 



Cottage and buttermilk cheese are not ripened cheeses in the 

 commonly accepted sense. The bacteria and molds which are 

 active in producing fully ripened cheeses have been studied ex- 

 haustively in a few instances, and cultures are now used for the 

 manufacture of several types of cheese. Camembert cheese has 

 been studied more thoroughly than any other type and the micro- 

 biology of several others is fairly well understood, as Emmen- 

 thaler, Cheddar, and Roquefort cheeses, for example. 



Emmenthaler cheese has been studied by several European 

 and American investigators. The chief groups of micro-organ- 

 isms are the common lactic acid bacteria, liquefying micrococci, 

 and lactobacilli. The holes or eyes in this cheese are of particular 

 interest and the number and size of the holes serve as a guide for 

 judging its quality. A "bhnd" cheese, that is to say, one with- 

 out holes, is of small value in the market. Formerly it was be- 

 lieved that these holes were caused by gas formed from milk- 

 sugar by bacteria of the Bacillus coH group. This theory is not 

 tenable, since milk-sugar disappears within a few days after ripen- 

 ing commences, while holes appear at later stages of ripening. The 

 theory now held by some is that propionic acid bacteria decompose 

 calcium lactate, with formation of gas, and that this gas forms the 

 holes. The calcium lactate is formed by lactic acid combining with 

 the calcium of casein. According to Clark, the gas consists of carbon 

 dioxid and nitrogen. The nitrogen gas is derived from air origin- 

 ally contained in the curd and is not produced by bacterial action. 

 Eldredge and Rogers could not find propionic acid bacteria in 

 three samples of Emmenthaler cheese made in Wisconsin. They 

 did find them by the same bacteriologic methods in a special 



