Cereal Chem 58:309 - 310.  |  VIEW ARTICLE
Effects of Moisture and Temperature on Microbiological and Sensory Properties of Wheat Flour and Corn Meal During Storage.

R. J. Bothast, R. A. Anderson, K. Warner, and W. F. Kwolek. Copyright 1981 by the American Association of Cereal Chemists, Inc. 

Wheat flour and corn meal were stored at moistures ranging from 11 to 18% and temperatures of 25 and 34 C for 18 months. Samples were assayed at 0, 0.5, 1.5, 3, 6, 9, 12, and 18 months. Microbial quality was monitored during storage by determining CO2 in the headspace of each storage container and the total aerobic bacteria and mold counts. A sensory evaluation was made on each product. In general, bacteria did not grow under the relatively dry conditions used in this study, and their numbers diminished with time. However, mold counts increased in products stored at 15 and 18% moisture, reaching maximum numbers by three to six months, and then decreased during the remaining storage. Aspergillus glaucus and A. candidus were the predominant molds observed. Generally, increases in CO2 in the headspace paralleled increases in mold counts and could be used to detect early microbial activity. High CO2, high mold counts, and low flavor and odor scores were associated with storage of both products at 15-18% moisture and at 25 and 34 C. This study indicates that product quality cannot be maintained beyond six months at 15% moisture and 25 C or beyond 15 days at 18% and 25 C. Quality deteriorates more rapidly at 34 C than at 25 C at these moisture levels.