Cereal Chem 44:288 - 299.  |  VIEW ARTICLE
Bacterial and Actinomycete Flora of Kansas-Nebraska and Pacific Northwest Wheat and Wheat Flour.

R. R. Graves, R. F. Rogers, A. J. Lyons, Jr., and C. W. Hesseltine. Copyright 1967 by the American Association of Cereal Chemists, Inc. 

Wheat and flour samples from 11 representative flour mills in the Kansas-Nebraska and Pacific Northwest wheat-producing areas were examined for their bacteriological content. Examinations were made for total aerobic bacteria, psychrophiles, fecal streptococci, salmonellae, coagulase-positive staphylococci, catalase- negative bacteria, thermophilic spores, and actinomycetes. The standard method for estimating total aerobic bacteria was improved through the use of cycloheximide (Actidione) as a fungal inhibitor. In general, total and differential counts were low. Counts for total bacteria ranged from 220 to 20,000/g. in flour and from 15,000 to 660,000 in wheat. These counts were consistently lower in the finished flours than in the parent grains. Actinomycete counts ranged from 0 to 5,300/g. of flour and from 0 to 300/g. of wheat. Tests for salmonellae and coagulase-positive staphylococci were negative in the samples examined. Some 532 cultures of bacteria were isolated for taxonomic studies. The most frequently encountered and widely distributed bacteria in wheat belonged to the genus Flavobacterium; in flour the dominant organism was Paracolobactrum aerogenoides. Of the 228 actinomycete cultures isolated, Streptomyces albus predominated.