RopiNKSs IN Milk and Cream. 405 



ing that the same is true in America, there is every reason to 

 believe that ropiness in milk caused b}^ Bacilhis lactis viscosus can 

 be prevented. Whether these particular bacteria are conveyed 

 from brook water to the milk through the agenc}^ of the cows' 

 udders, or directly to the milk utensils b}^ the water used in 

 washing them, proper precautions should prevent trouble from 

 those sources. Where the trouble occurs, particular care should 

 be taken to avoid the use of unboiled water for cleaning utensils 

 and to prevent the cows from wading in water. 



It seems highly probable that ropiness would not appear in 

 milk handled in sterile utensils and consumed within 24 hours. 

 The evidence at hand indicates that ropiness becomes trouble- 

 some in establishments handling milk, only when it is allowed to 

 stand for some time, as in butter making. Milk, when drawn 

 with ordinary precautions, contains a considerable number of 

 species and among them may occasionalh' be found the one in 

 question or others capable of producing ropiness. The low tem- 

 perature at which milk is kept in the deep setting process of 

 creaming is unfavorable to the multiplication of most of the 

 bacteria commonly present in milk, but does not entirely check 

 the growth of Bacilhis lactis viscosus. Owing to the unusual 

 faculty of growing at a low temperature, that bacillus, or any 

 other possessing that faculty, might readily come to predominate 

 even w^hen originally introduced in small numbers. The imper- 

 fect cleansing of infected cans, together with their indiscriminate 

 use for containing the market milk and the cream, results in the 

 spread of the infection through all of the utensils in the estab- 

 lishment and to those of the consumer as well. In creameries 

 where butter is made and milk is also sold, exceedingly great 

 care must be taken in scalding utensils used for creaming. 



In an outbreak of ropy milk in Michigan, Marshall concluded 

 that the bacteria* fell into the milk from the udder during milk- 

 ing. Unfortunately the organism described by Marshall can- 

 not be positivel}^ identified from the brief description available 

 but there is reason to suspect its identity with Bacilhis lactis 

 viscosus. The results of Marshall's investigations indicate that 



* Bulletin No. 140, Michigan State Agricultural College Experiment 

 Station. 



