Production and cleaning of spores of putrefactive anaerobe 3679.

Putrefactive Anaerobe strain 3679 (PA 3679) is of interest to the food microbiologist because it has been responsible for the microbial spoilage of certain types of thermally processed foods. It is also of interest because the spores of this organism have a high degree of heat resistance and their thermal death rate is frequently used in the calculation of thermal processes for low acid canned foods. Previous procedures for producing spores of PA 3679 have required complex media and long incubation periods: Reed et al. (1951), Heiligman et al. (1956), McClung (1935), National Canners Association (1954), and Roth and Halvorson (1952). In addition, many of these media contain particulate material which is difficult to remove from the spore harvest. The objectives of this investigation were two-fold: (a) to develop a clear medium which would stimulate vegetative growth as well as maximum sporulation within shorter incubation periods and (b) to devise a cleaning procedure, without the use of heat, which would effectively remove the vegetative cells and debris from the harvested spore crop without impairing the viability of the treated spores.