Canning Safely, for Your Safety

— Written By and last updated by Patricia Burch

It’s almost summer time, which means canning season is almost here! Stands with fresh local strawberries, blueberries, and watermelons are on popular street corners from here to Duplin County and beyond. These nutrient rich fruits are the perfect items to make preserves, jams, and jellies. Although canning is a fun way to preserve foods, it can be quite dangerous if certain precautions are not taken.

Canning techniques have been around for 200 years. These techniques have been taught from generation to generation and have been very useful in preserving foods that may spoil quickly, may be in abundance, or to eat foods in a different way. The most important pathogen to consider when canning is clostridium botulinum, a spore forming bacteria that forms under conditions without oxygen. This toxic bacterium can be very dangerous when consumed even in small amounts. Although it is pretty rare in the United States, it is primarily associated with improperly home canned foods. This is why it is so important to follow science-based recipes and to make sure all parts of your canner are working properly. To destroy clostridium botulinum, boiling foods for ten minutes at altitudes below 1,000 feet should destroy the poison if it is present. After a 1,000 feet elevation, an additional minute should be added per 1,000 feet. Most of Sampson county is below 1,000 feet, but you may check online to find your exact elevation.

There are two different kinds of foods that are typically canned, low-acid and high-acid. Foods that are low-acid pose a greater risk of clostridium botulinum. These are foods like meats, dairy, and vegetables. Foods that are high-acid are more likely to block or destroy clostridium botulinum when heated. These are foods like fruits, pickles, sauerkraut, jams, jellies, marmalades, and fruit butters. Water-bath canners are acceptable to use for high-acid foods, but pressure canners are the only safe way to can low-acid foods. Be sure your pressure canner has no rips or tears in the gasket (the rubber circular piece that fits inside the lid) and that your dial gauge is correct. I will be testing dial gauges from 9 a.m. – 12 p.m. at the Duplin Extension office May 31st and June 1st and at the Sampson Extension office June 7th and June 8th. I also recommend you bring your whole pressure canner lid so that I can check the gasket as well. Please take advantage of this opportunity to make sure your pressure canner is producing foods at the correct temperature. I will also be providing Ball Blue Books for $5. Pressure canners must process foods at 240 degrees Fahrenheit (10-11 lbs. of pressure) in order for them to safely preserve foods. Having a gauge that is not correct can cause unsafe foods or canning accidents.

Canning is a fun way to preserve foods. I will be teaching some preservation classes in the future and will keep you all informed of when those will be held. If you want to learn more about canning or have any questions, please contact Sydney Johnson at the Sampson County Extension office.