55° MICROBIOLOGY OF SPECIAL INDUSTRIES 



of the acetic bacteria. They produce butyric acid and putrid odors 

 and, if neglected, may completely spoil the vinegar. Sulphuring, fining, 

 and pasteurization are the remedies. 



Darkening or persistent cloudiness may be caused by oxidase as in 

 wine and cider and is controlled in the same way. A similar defect may 

 be caused by the tannic extractive matters of new casks or contact with 

 iron. Aeration followed by fining will remove the cause of the trouble. 



