Home Canning & Food Preservation

Canning is a great way to preserve produce that you have grown or bought at a farmer’s market. The key with home canning is that it has to be done safely and correctly. If not, your canned foods can grow bacteria that cause botulism—an often fatal illness caused by a nerve toxin.

Maintaining Quality

To make sure you produce high quality canned foods that won’t make you or your family sick, use the following tips:

Follow the latest canning methods and recommendations. Make sure your food preservation information is based on up-to-date, scientifically tested guidelines. Do not use outdated publications or canning recipes.
Use the right equipment for the foods you are canning. Pressure canning is the only recommended method for canning vegetables and other low acid foods. Using boiling water canners for these foods increases your botulism risk.
Use the best quality foods. Examine produce for freshness and discard any diseased or moldy food. Try to preserve food the day it’s harvested.

Food Acidity & Processing

In canning, foods are divided into two groups: high acid and low acid foods. To control for botulism, low acid foods should be processed in a pressure canner, and high acid foods can be processed using a boiling-water canner. Acidity can be natural (e.g., most fruits) or added (e.g., pickled food).

Acid in high acid foods (pH lower than 4.6) prevents germination of spores of C. botulinum bacteria after the boiling water bath canning process. Low acid foods cannot do that, so low acid foods must be processed in pressure canners that can heat low acid foods to the temperature needed to destroy bacterial spores.

Instruction & Resources

For in-depth information on home canning, contact your local Extension office or view our list of counties (796KB pdf) that will offer classes on home canning this year. You can also look through our wide variety of tested, approved canning recipes for reference.

The National Center for Home Food Preservation is also a reliable source for current research-based recommendations for home food preservation.