[HARRISON] VISCOUS FERMENTATION OF MILK AND BEER 77 



Griïbcr ''* in the same year also isolated from milk a coccus, named 

 by him Coccus lactis viscosi, which had a distinct tendency to divide in 

 two directions at right angles to one another, and which caused milk 

 to become ropy and slimy. The milk was at first alkaline and later 

 acid in reaction. This organism liquefied 15 per cent gelatine and the 

 colonies on this medium were characteristic. It grew better in the 

 absence of oxygen. The same author,'^ also isolated a chromogenic bacil- 

 lus from milk, Bacillus lacio ruhifaciem, which produced a rose red 

 pigment in milk and also made it somewhat slimy without undergoing 

 subsequent peptonization. 



Burri ■*'^ has instanced an interesting outbreak of a slimy fermenta- 

 tion in a cheese factory (which made Emmenthaler cheese), in the 

 Canton of Thiirgau, Switzerland. The whey which came from the 

 cheese made in this factory, 8 or 12 hours after making, was slimy 

 or ropy. The surface of the cheese also became covered with whitish 

 spots caused by the accumulation of viscous whey. The factory was 

 only able to produce a very inferior product for a whole year on 

 account of this trouble. A fermentation test of the milk supplied 

 showed several samples which gave a ropy serum. Burri isolated from 

 affected whey an organism very similar to B. lactis acidi, but which 

 showed a slimy character. Microscopically, the organism appeared like 

 Bacterium guntheri, the ordinary lactic acid organism, but the viscous 

 consistency of the colonies seemed to indicate that it was a special variety 

 of this organism. The same organism was isolated from all the factory 

 cheese, but in normal, fresh cheese the ordinar}' lactic acid bacteria 

 were alone present. From an extensive investigation of the sources of 

 the milk supply, Burri was able to demonstrate the presence of the 

 organism in the udders of some of the cows. The bacillus produced its 

 viscosity best at 38°. 



Soapy milk, a term applied to milk which exhibits a taste of soap 

 and lye, is related to the slimy fermentation in that a slimy sediment 

 is deposited after the growth of the organism in milk. Herz *^ was 

 the first to notice and record this afi;ection. It was subsequently inves- 

 tigated in 1893 by Weigmann and Zirn,'*- who isolated a bacillus, B. lactis 

 saponacei, which converted normal milk into a solution with a slimy 

 sediment. This bacillus was afterwards discovered in the straw, which 

 was in a damaged condition. 



EoPY Beee. 



As already mentioned, Pasteur was the first to study this phenome- 

 non in beer, and mentioned its resemblance to ropiness which occurred 

 in wine. 



