DAIRY FARMING — DAIRYING. 77 



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capsule which by its stickiness causes viscositj', but this condition vanishes 

 wlien the milk curdles. An account of certain types of Streptococcus lacticus, 

 which are able to peptonize the casein if kept at low temperatures (between 15 

 and 20° C. ) , was given by C. Bartel. These types of lactic acid bacteria are re- 

 garded as of importance in the ripening of cheese which generally proceeds at 

 low temperatures. The author has found that temperature exerts considerable 

 influence upon the proteolytic power of lactic acid bacteria, higher temperatures 

 favoring the disintegration of lactose, while lower temperatures promote the 

 degradation of the casein. It is said that the finding of these bacteria empha- 

 sizes the necessity of classifying according to physiological functions rather 

 than morphologically in order to make proper selections of bacteria for cheese 

 making. 



The necessity of employing lactic acid bacteria in general in cheese manufac- 

 ture, in order to improve the taste and appearance and prevent spoilage, was 

 pointed out by E. Kayser, Lohnis, A. Peter, et al. Gratz, who divides these 

 bacteria into three classes, viz, micrococcus, streptococcus, and bacillus, re- 

 marked that the type most generally used is Streptococcus lactis, while Bacillus 

 lacticus is used less frequently, and still less the combination of the three types. 

 Evans and Hastings observed that in order to produce a typical Cheddar cheese 

 four morphological groups, viz. Bacterium lactis acidi, B. casei, the strep- 

 tococcus, and the micrococcus are required, B. lactis acidi giving a sour taste, 

 the streptococcus a delicate acidulous taste, and B. casei a tart taste, and that 

 the best aroma is obtained if tlie pasteurized milk is inoculated with a mixture 

 of B. lactis acidi, streptococcus, and micrococcus. O. Jensen credited the great- 

 est importance to B. casei and von Freudenrich to the ferments of propionic 

 acid. The author believes it is too early to give preference to one species of 

 lactic acid bacteria over the others. 



The author presented the experience of the " Pro Grana " Association on the 

 manner of employment of the lactic acid bacteria. It is said th*t the employ- 

 ment of pure cultures should be accompanied by a hygienic standard in the 

 production, collection, and treatment of the milk. Impure rennet that carries 

 living ferments into the milk besides the enzyms desired should be abandoned. 

 The rennet commonly used for Swiss cheese is of this sort, being prepared by 

 an extraction of calves' stomachs. It often contains cultures of ferments that 

 are detrimental to cheese production. 



R. Ostertag, in discussing the sanitary control of milk, stated that in order to 

 detect the abnormal infection of milk by acid-rennet-forming bacteria and 

 distinguish it from that by common lactic acid bacteria the test by the lacto- 

 zymoscope does excellent service, the former bacteria provoking the character- 

 istic, rather soft curd with an abundant generation of clear whey which makes 

 cheesy milk and is clearly distinguished from the firm, dry, porcelainlike 

 coagulum produced by the common lactic acid bacteria. The zymoscopic method 

 not only affords a means of judging the condition of milk with reference to 

 cheese making and calling attention to abnormal if not pathological conditions 

 of the udder, but, since such conditions are largely due to imperfections in 

 milking, it may also offer the veterinarian reliable data for detecting faults 

 and carelessness in milking which at times cause disturbances in the manufac- 

 ture of cheese and decided pathological symptoms. Such control will be par- 

 ticularly valuable if applied to the milk from individual cows or even each 

 separate quarter of the udder. 



Bacteriolog'ical studies on two yellow milk organisms, B. W. Hammer 

 {loica Sta. Research Bui. 20 (1915). pp. 135-149, figs. 2). — The morphological, 

 cultural, and biochemical characteristics of two organisms, isolated in the dairy 



