Beware Unsafe Canning Practices

— Written By Tracy Davis
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Home canned jars of green beans, peaches, and other foods with fresh tomatoes in foreground.

Home canned food and fresh vegetables.

In a previous article, I shared information about preparing for the canning season by gathering all the proper equipment and supplies. Now that the harvest and canning season is in full swing, its important to follow research-based guidelines and be aware of unsafe practices.

Canning is a time-consuming endeavor and we can be tempted to try shortcuts to save time and energy. Unfortunately, these shortcuts often lead to unsafe food. Preserving food is not a creative activity, rather a researched science process where safety must come first. Proper canning procedures are meant to kill spores of Clostridium botulinum, the bacteria that causes the potentially deadly botulism poisoning.

Some examples of unsafe canning practices include open-kettle, dry canning, oven and dishwasher processing, and using pressure saucepans/cookers instead of canners. The open-kettle method involves cooking food for many hours on the stove, then placing food in jars and storing them without any further processing. Another form of this method is placing filled jars in conventional ovens, microwave ovens, or dishwashers for “processing”. None of these appliances are safe alternatives to pressure canners. Pressure saucepans/cookers and electric multi-cooker appliances are not recommended for canning either.

The latest version of people making up their own method that is potentially very hazardous involves putting raw vegetables in canning jars with no added liquid, placing lids on jars, and pressure canning for the same amount of time as if you had added water to the jars. This is called dry canning and is extremely unsafe. In the recommended procedures, the liquid covering the vegetables in the jars is required for the expected heat penetration throughout the jars during processing.

The risk with each of these unsafe practices is botulism, a fatal food poisoning disease. Botulism toxin can be present in canned vegetables without any visual changes to the food. Therefore, you could eat home canned food that looks, smells, and tastes fine without knowing it is contaminated with botulinum.

When asked about canning methods seen on social media, Pinterest, or similar sources, I often hear “people say it works and they like the food”. Certainly, someone can get lucky and not get sick from trying their own method. However, is the risk really worth the few minutes of time or effort that you save? The USDA recommended canning processes are meant to be used with the full procedures as written – how to select and prepare the food, how to fill jars, how to manage each step in using a pressure canner, and how to make altitude adjustments.

Preserving that fresh garden taste to enjoy all year long is surely one of the best reasons for canning food at home. Following the proper procedures fully from start to finish will ensure those garden vegetables are safe to eat next winter and the extra time and effort will have been worth it.

Publications, guides, and recipes for home canning are available through N.C. Cooperative Extension of Rutherford County or you can visit the National Center for Home Food Preservation website where you will find the USDA Complete Guide to Home Canning as well as many other resources.