eatrightPREP Registered Dietitian (RD) Practice Exam

Improper home canning creates an anaerobic, low-acid environment where Clostridium botulinum can thrive. The spores of this bacterium are heat resistant and can survive typical canning temperatures, so if processing isn’t done with adequate heat (usually a pressure canner for low-acid foods), the spores can germinate and produce botulinum toxin. This toxin is extraordinarily dangerous, capable of causing severe illness and death, which is why botulism is the primary safety concern with improperly canned foods. Other organisms listed are associated with different situations—Staphylococcus aureus can cause toxins in foods left at room temperature, Saccharomyces cerevisiae is a yeast that ferments and spoils food but isn’t the main hazard in canned products, and Aspergillus flavus produces aflatoxins in stored grains and nuts rather than in the canning process.