4.8 okra
5.0 pumpkins, carrots
5.1 turnips
5.2 beets, string beans
5.4 sweet potatoes
5.5 spinach, asparagus
5.6 baked beans
5.7 red kidney beans
5.9 lima beans
6.0 succotash
6.2 peas
6.3 corn
7.0 hominy, ripe olives
Commercial canneries, which are regulated by the Food and Drug
Administration, use similar processes to assure safe canned foods. In
the past 50 years, 75 percent of the reported cases of botulism in the
United States have been caused by home-canned food while less than 10
percent have been caused by commercially canned food. If proper
home-canning procedures are followed, botulism from this source could
virtually be eliminated as a cause of death in the US.
On the lower side of pH 4.6, acid content of the food will prevent
growth of _Clostridium botulinum_ and most of the other spore-forming
bacteria. Thus, these foods can be preserved by using a lower heat
treatment. The most common types of spoilage micro-organisms associated
with acid foods are yeasts and molds. These organisms are acid-tolerant
and can grow in an acid environment. They are killed at a lower
temperature than spore-forming bacteria. Acid foods only need a heat
treatment in a boiling water bath for a specified time to destroy the
microbes present.