Germination of spores of certain aerobic bacilli under anaerobic conditions.

Previous work by this laboratory (Roth et al., 1955) has established that a definite aeration requirement existed for spore formation of Bacilus anthracis and Bacillu globigii. This aeration requirement was shown to be different at various stages of growth. In the case of spore germination of the aerobic organisms tested, the present work indicates that the necessity for aerobic conditions is completely lacking. Many early reports have suggested that aerobic spore-forming bacteria could grow under anaerobic conditions in canned foods. Weinzirl (1919) was among the first to show that aerobic spore formers were associated with spoilage in canned foods; but he believed that this type of spoilage was generally aociated with air leaks. Savage (1923) was unable to prevent the growth of BaciUus ubtili8 and Bacillus mesenteius under the most rigid anaerobic conditions he could devise; as a result, he concluded that spoilage in canned foods could be caused by aerobic spore formers in the absence of air. Cheyney (1919) reported that B. mewentericus did not appear to be strictly aerobic. In a series of experiments with B. subtilis and B. meentericug, Bushnell (1922) found these organisms capable of growth to some extent in what he considered to be as complete anaerobic conditions as it was possible to obtain. Basset (1933) claimed that he observed growth of B. anthracis anaerobically and that his cultures sporulated after incubation in the absence of air in 6 days. The present study has shown that spores of certain aerobic organisms will germinate readily under anaerobic conditions. However, in our work, no appreciable growth or sporulation in the absence of air over extended incubation periods has been demonstrated.