Post-Processing Spoilage of Low-Acid Canned Foods by Mesophilic Anaerobic Sporeformers

Over a period of 4 years, 770 low-acid canned food spoilage incidents were investigated to determine the cause of spoilage. In 27 of these, the cause was attributed to the growth of bacteria of the Clostridium genus that had entered the cans as a result of post-processing leakage. No correlations were found that might explain the occurrence of this mesophilic anaerobic type of spoilage. It appears to be a random event, probably linked to cannery insanitation. A variety of species was found, consisting of both proteolytic and non-proteolytic types. Clostridium botulinum was not isolated from any of the canned foods examined, nor were any of the samples found to contain botulinal toxin. Container leak test methodology and principles are discussed.