240 ANNUAL REPORTS OF DEPARTMENT OF AGRICULTURE 



nary in character. The use of " starters " has resulted in some im- 

 provement of the texture and possibly a suppression of gas formers. 

 On a commercial scale conflicting results have been obtained. 



Cheddar cheese. — Experiments in coating cheese with paraffin to 

 improve its keeping qualities have been made to determine the tem- 

 perature at which paraffin should be applied, the length of the appli- 

 cation, and the age of the cheese at which it is best to apply the 

 paraffin. The best results were secured with paraffin at a temperature 

 of 240° F. when the cheese was three days old. 



Some preliminary work has been done on the feasibility of canning 

 cheese of the Cheddar type directly from the press. Cheese put up 

 in this way ripens normally, but has a softer texture than ordinary 

 cheese. This work will be continued by comparing canned cheese 

 with cheese made from the same vat and ripened in the ordinary way. 



A study is being made at Madison, Wis., in cooperation with the 

 Wisconsin Experiment Station, of such problems as the influence of 

 various factors, such as acidity of milk, proportion of rennet used, 

 size of curd cubes, time, temperature, pressure, etc., on the moisture 

 content of cheese. The results thus far obtained have been published 

 in Bulletin 122. 



As a result of the investigations in making cheese from pasteurized 

 milk the method has been so perfected that it is possible to bring 

 factory milk into practically uniform condition every day, so that a 

 definite routine method of manufacture may be followed throughout 

 the year. From February to July, between 150 and 300 pounds of 

 cheese were made daily by this process. The cheese has been very 

 uniform in quality, has had a clean, mild flavor, free from taints, and 

 an almost perfect texture. This cheese has been sold at the highest 

 market price. On account of its good texture and the tendency to 

 hold its shape, a large part of this cheese has been shipped to the 

 Southern States, and the reports indicate that it is superior for this 

 purpose to the ordinary cheese. 



An extended study has been made of the volatile fatty acids and 

 esters formed in the ripening of normal cheese and in cheese made 

 from pasteurized milk, and their relation to the development of 

 flavor. These products have been found absent in cheese treated with 

 chloroform, indicating that their origin is due to a biological factor 

 or enzymatic agent produced by lactic-acid organisms. 



Soft cheese. — Several European varieties of soft cheese are of 

 great commercial importance in the United States, and for a number 

 of years the Dairy Division has been investigating them in coopera- 

 tion with the Storrs (Conn.) Agricultural Experiment Station, with 

 a view to their production in this country. 



Most of the problems connected with the production of the Camem- 

 bert type of cheese in the United States have been fully covered and 

 the results obtained have been published in several bulletins of this 

 Bureau. During the early part of the year the enzym experiments 

 were continued, particular attention being given to the enzym that 

 was found to be directly concerned in the ripening of this cheese. 

 It is necessary to resume some portions of this work at a later time. 

 It is also contemplated to continue experiments in order to study 

 three points not fully covered in previous reports, namely, the effect 

 of relative humidity of the air in the ripening room upon the water 



