This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Strong, D. H. Articles by Duncan, C. L. Search for Related Content PubMed Articles by Strong, D. H. Articles by Duncan, C. L. Agricola Articles by Strong, D. H. Articles by Duncan, C. L.

 Previous Article  |  Next Article 

Appl Environ Microbiol. 1970 June; 19(6): 980-987
Copyright © 1970 American Society for Microbiology. All Rights Reserved.

Influence of Water Activity on the Growth of Clostridium perfringens

Department of Food Science, Food Research Institute, and Department of Bacteriology, University of Wisconsin, Madison, Wisconsin 53706

ABSTRACT

Each of four strains of Clostridium perfringens was grown in modified fluid thioglycolate medium which was adjusted to yield selected water activity (a_w) levels. The adjustments to secure the desired a_w levels were made with NaCl, KCl, or glucose. At each a_w level, further modification was effected to produce four pH values. Cultures were incubated at either 37 or 46 C. The solute used to achieve the reduced a_w levels appeared to have a definite effect on the magnitude of growth achieved, the rate of growth, and the limiting a_w at which growth would occur. Use of glucose as the controlling solute permitted growth at the lowest a_w level tested, 0.960, and yielded the greatest magnitude of growth as measured by turbidity values, at all of the a_w levels investigated. Cultures grown in the medium with added KCl generally demonstrated the longest lag times and the least amount of growth. Regardless of specific solute used, as the a_w level was lowered and the pH value decreased within each a_w level, the rate and amount of growth were lessened. It appeared, however, that low pH values had less effect on inhibiting growth at low a_w levels than at higher a_w levels. Those cultures incubated at 46 C generally exhibited shorter lag periods than those at 37 C, although the maximal growth attained was somewhat less than that achieved at 37 C. The response to all of the investigated conditions was similar for each of the four strains tested.