Effect of Carbon Dioxide, Nitrogen and Hydrogen Gases on Germination of Clostridium botulinum Spores

Abstract

Gennination of spores of Clostridium botulinum strains 62A, 2138 and 12885A was monitored in modified peptone yeast extract broth flushed with CO 2 • N 2 • CO 2 + H2 and N2 + H 2. Carbon dioxide enhanced germination of spores of each of the strains. Hydrogen gas in combination with CO 2 or N2 did not substantially alter germination compared to germination in CO 2 or N2 alone, even though the oxidation-reduction potential of the system was lower in the systems flushed with H 2. Enumeration procedures for anaerobic organisms including Clostridium botulinum often dictate flushing with anaerobic-grade gases (9). Typically, combinations of CO 2 • N2 and H2 gases are used. Carbon dioxide has been shown to enhance germination and growth of Clostridium species and growth of other anaerobic organisms (6,10,11,14,16,19). These reports deal primarily with Clostridium perjringens, Clostridium bifermentans and PA 3679 spores. Wynne and Foster (19) in 1948 established the beneficial effect of CO 2 on C. botulinum 62A spore germination. However, their earliest sampling time was 20 h so that information on the rapidity of germination and details of the germination rate in CO 2 cannot be determined from their study. Information on the effect of other gas environments on the germination of C. botulinum spores also is lacking. Gas flushes may be used for the preservation of foods (7). There is increasing interest in extending the shelf-life of foods by packaging in nitrogen or other gas atmospheres (3,4,12,13), C. botulinum types A, Band E can produce toxin in nitrogen-packed hamburger or sausage sandwiches (13). Little information is available on the effect of various gas atmospheres on C. botulinum spores. The objective of