Food preservation is a very hot topic this year and there are a couple of reasons for this. With our struggling economy, people are looking for economical ways to feed their families. In addition, because people are becoming more conscious about their diets, they want to know where their food comes from and exactly what is in it. They want to control the content of their food and may want to limit or eliminate such things as sugar, salt, additives, preservatives, artificial colors, etc. Canning fresh produce and meats at home can give consumers more control over what they put into their bodies, which is a good thing.
What many people may not realize is that some of the produce that is grown these days has a lower acid content than produce that was grown thirty or forty years ago due to the development of lower-acid varieties of plants. For example, many of the tomatoes that are available for consumption today need a different preservation process due to their lower acid content; in fact, tomatoes must be acidified before home canning to make them safe to eat.
All of the canning recommendations have been updated June 2009, which is why updating your canning skills is so important. USDA is the basis for all research-based recommendations. Information you see on the Internet, in popular media or on TV shows is not always research-based and may not be safe.
The main concern with home food preservation is the bacteria Clostridium botulinum commonly called botulism. You cannot see, smell or taste botulism. It is not visible spoilage like mold or yeast. Therefore, in order to make sure you and your family are safe from botulism poisoning, following the correct, updated guidelines for home food preservation is absolutely crucial. Incorrect pressure canning procedures can have deadly consequences. Very few people survive botulism poisoning and the few who do have long-term health consequences. It only takes six to ten cells of the botulism toxin to make you deathly ill.
Pressure canning is particularly tricky to get right. Vegetables, meat, poultry, seafood and legumes all have the potential to contain the botulism bacteria. The bacteria are prevalent in western soils, however, it is harmless to humans in the soil or if food is cooked on a stove. However, when sealed in a bottle and pressure canned incorrectly, the bacteria can change from a vegetative state into a spore if conditions are just right. The conditions that foster a bacterium to change into a spore and become deadly for human consumption are low acid content, high protein, an anaerobic environment and high moisture content. These are exactly the conditions that home food processors create when they can food. The only way to kill the spores that produce the botulism is by applying intense, prolonged heat. That is why correct pressure canning procedures are crucial.
Three critical errors can be made in pressure canning. The first is not venting the pressure canner for a full ten minutes regardless of manufacturer's instructions. The internal pressure of each individual bottle must reach 240 degrees to kill the bacteria. Neglecting to vent the pressure canner allows too much air to remain in the canner, which will prevent the bottles in the canner from reaching 240 degrees. Second, not making altitude adjustments is another problem home canners may make. The proper way to make adjustments for a specific altitude is to increase the poundage. It is very important to make the correct adjustments in order to keep your food safe to eat. Third, not having the pressure canner dial gauge tested at least annually. Obviously, a faulty gauge will yield inaccurate results. It's best to have your pressure canner dial gauge tested before you begin the canning season each year. We test gauges here at the Extension Office any time for $2 or free on the second Tuesday of each month. You can bring the whole lid of the pressure canner into our office; you don't need to disassemble the gauge from the lid. The Extension Office will be holding a Pressure Canning Workshop on July 22 from 10am to 3pm for a cost of $15. The workshop will teach correct pressure canning procedures to prevent food spoilage and food borne illness. Participants will be able to take the results of the canning workshop home. Call the Extension Office at 267-3235 to reserve a spot in the class.
Additional information on food borne illness and its prevention can be obtained from the National Center for Home Preservation and Resources for Idaho websites. For the latest, downloadable USDA complete Guide to home canning, visit www.uga.edu/nchfp/index.html
. Many publications are free to download at www.info.ag.uidaho.edu:591/catalog/default.htm