Why must low acid foods be processed under pressure?
Temperature of boiling water is 212 degrees; at that temperature it is very difficult to destroy the Clostridium botulinum spores, even by lengthy processing. Clostridium botulinum thrives in a low acid food in a vacuum (without air) and produces a toxin which can cause botulism. A combination of time and temperature is recommended which will destroy the organism and keep the product safe. This necessary temperature cannot be reached in a boiling water bath; however, a steam pressure canner can reach temperatures higher than 212 degrees F.
Barbara Willenberg, Nutritional Sciences, University of Missouri-Columbia
Last update: Tuesday, May 05, 2009