2 BULLETIN 148, U. S. DEPARTMENT OF AGRICULTURE. 



the product would equal in quality that made in Europe, since the 

 same methods were used on both sides of the Atlantic. 



The most serious trouble of the cheesemaker occurred during the 

 cold months, which led to the practice of making cheaper varieties 

 of cheese in the spring and fall and closing down the factory for four 

 months in the winter. This, of course, is a considerable handicap to 

 the industry, and would not be necessary if there were sufficient infor- 

 mation concerning the origin of and remedy for the faults in manu- 

 facture. These unsatisfactory conditions led to the investigations 

 reported in this bulletin, since it was believed that the present faulty 

 methods might be corrected, provided the real causes of cheese defects 

 were discovered. 



In the absence of exact knowledge it was natural that erroneous 

 theories should become prevalent in regard to the feeding of the cows, 

 the care of the milk, and the handling of the cheese ; but as they were 

 based on practical experience it has not been found advisable to set 

 them aside without investigation. Apparently very unimportant 

 changes made in handling the cheese were found to result in great 

 changes in the quality of the finished product, and although changes 

 in methods are necessary in order to produce the best quality of 

 cheese, it is unwise to advise the cheesemaker to change his methods 

 without substantial proof of the value of the change. 



The main trouble in making Swiss cheese is known to be caused by 

 the development of undesirable types of microorganisms, some of 

 which produce abnormal gas, causing what is known as " nissler " or 

 "pressler" cheese. These undesirable organisms in Swiss cheese 

 cause a lack of uniformity in the formation of the eyes. In some 

 cases no eyes whatever are developed ; this trouble is probably due to 

 the absence of certain desirable types. At the beginning of this work 

 it was thought that these faults might be overcome by the proper use 

 of starters, which have become general in buttermaking, and their 

 value has been frequently demonstrated. They have also been used 

 to some extent in the making of Cheddar cheese. Unconsciously the 

 makers of Swiss cheese have used starters with the rennet, a practice 

 which has at times been of great value. But while the rennet starter 

 has been the cause of much help, it has also caused trouble when the 

 helpful species of bacteria usually present have for some reason been 

 weakened. The full benefit of the starter was not obtained, in any 

 event, since less than one-fourth of 1 per cent of rennet was used. 



THE SIGNIFICANCE OF BACILLUS BULGARICUS IN MAKING SWISS 



CHEESE. 



In selecting a starter for making Swiss cheese it is at once apparent 

 that certain characteristics are desirable to make its use possible 

 with the method of manufacture employed. The curd for Swiss 



