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 Similar articles in PubMed 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 Shockey, W. L. Articles by Dehority, B. A. Search for Related Content PubMed PubMed Citation Articles by Shockey, W. L. Articles by Dehority, B. A. Agricola Articles by Shockey, W. L. Articles by Dehority, B. A.

 Previous Article  |  Next Article 

Appl Environ Microbiol. 1989 July; 55(7): 1766-1768
Copyright © 1989, American Society for Microbiology. All Rights Reserved.

Comparison of Two Methods for Enumeration of Anaerobe Numbers on Forages and Evaluation of Ethylene Oxide Treatment for Forage Sterilization

¹ Department of Dairy Science, Ohio Cluster, U.S. Dairy Forage Research Center, Agricultural Research Service, U.S. Department of Agriculture, and Department of Animal Science, Ohio Agricultural Research and Development Center, ² Wooster, Ohio 44691

ABSTRACT

Experiments were conducted to (i) compare most-probable-number (MPN) procedures with roll tube procedures for enumeration of forage anaerobic bacteria and (ii) evaluate the efficacy of using ethylene oxide to sterilize wet herbage. Alfalfa, corn, and alfalfa-orchardgrass silages and alfalfa and orchardgrass herbages were analyzed for total anaerobic bacteria (medium pH, 6.8) and acid-tolerant anaerobic bacteria (medium pH, 4.5) by both roll tube and MPN procedures. No difference was found between the roll tube and MPN procedures for total bacteria; however, higher counts were obtained for acid-tolerant bacteria when the MPN procedure was used. Although MPN procedures require less time to obtain an estimate of bacterial numbers, isolation and identification of the microbial population is not possible. Alfalfa herbage was treated with ethylene oxide for 12, 24, or 36 h, incubated for 7 days at 37°C with or without addition of a bacterial inoculant, and analyzed for total bacteria by MPN procedures. Microbial growth after inoculation of ethylene oxide-treated herbage indicated that there was insufficient residual ethylene oxide to inhibit subsequent microbial growth. The results also indicated that 24 h was required to adequately sterilize fresh herbage. Thus, ethylene oxide can be used to sterilize wet herbage for use as a substrate for pure cultures of silage bacteria.

^* Corresponding author.

Manuscript 316-88, Ohio Agricultural Research and Development Center, The Ohio State University, Wooster.