BiocHEMiCAL Bulletin 



Volume I JUNE, 191 2 No. 4 



A STUDY OF ROPY BREAD 



ANNA W. WILLIAMS 



(Research Laboratory, Department of Household Science, University of 



Illinois, Urhana, III.) 



Introduction. Ropiness in bread has recently been receiving 

 considerable attention from investigators. However, its causes and 

 more especially the methods for its prevention are not yet thor- 

 oughly understood by the average baker. 



Various spore-forming bacilli belonging to the potato group 

 have been pfoved to cause ropiness, but B. mesentericus vulgatiis 

 (Flügge) seems to have been most often identified. Lafar^ made 

 note of Orth's Separation of three potato bacilH from slimy bread, 

 one of which gave a red color and was found to be harmless, while 

 the other two were considered as the cause of the disease. Wat- 

 kins^ obtained a pink colored crumb in a bread made from rope- 

 infected flour, but did not report any specific bacillus as the cause. 



The source of infection in most cases has been found to be the 

 flour, although occasionally the yeast has been held to be responsi- 

 ble. All investigators agree that moisture and warmth are favor- 

 able for the development of the bacilli and that, if bread made from 

 infected flour be kept at a sufficiently low temperature, ropiness will 

 not develop. Watkins has shown that acidity, produced by the 

 presence of lactic or acetic acid in the dough, retards and, when 

 present in sufficient amounts, entirely inhibits the growth of the 

 organism. 



The writer's attention was drawn to this study because of the 



^ Lafar : Handbuch der technischen Mykologie, 1908, ii, p. 522. 

 'Watkins: Ropiness in flour and bread, and its detection and prevention; 

 Jour. Soc. Chem. Indus., 1906, xxv, p. 351-354. 



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