Safe Home Canning: Just the Figures

Preserving food in jars at home using tested methods that destroy germs and seal the jar.

Key takeaways

• Low-acid foods: vegetables, meat, poultry and seafood must be processed in a pressure canner
• High-acid foods: most fruits, jams, pickles and properly acidified tomatoes can use a boiling-water canner
• Most useful single change: Use up-to-date tested recipes from the USDA or your local Cooperative Extension office.
• Commonest mistake: Oven canning, open-kettle canning or canning in a slow cooker or multicooker without a tested method.
• See a doctor if any of the signs under "When to speak to a doctor" below apply to you.

The numbers, in one place

In one paragraph

Home-canned vegetables are the most common cause of foodborne botulism outbreaks in the US, and botulism is a rare but potentially fatal illness.

Worth doing

• Use up-to-date tested recipes from the USDA or your local Cooperative Extension office
• Have the dial gauge on your pressure canner tested every year
• Use canning jars and new lids, and follow the recipe's headspace and processing time exactly
• Check seals after jars cool and refrigerate or reprocess any that did not seal

Worth avoiding

• Oven canning, open-kettle canning or canning in a slow cooker or multicooker without a tested method
• Using a boiling-water canner for vegetables, meat or soups
• Eating from jars that are bulging, leaking, spurting liquid when opened, or that smell bad; when in doubt, throw it out
• Inventing or changing recipes, such as adding more vegetables, onions or flour

Related topics

• What the Guidance Really Says About Cooking Methods (Healthy Recipes)
• Food and Water Safety Abroad: Sorting the Evidence From the Noise (Travel Health)
• What the Guidance Really Says About Fruit and Vegetables (Nutrition)
• Foods to Avoid in Pregnancy: What the Evidence Actually Says (Pregnancy and Postpartum)

Where to go next

• A Q and A on Safe Home Canning
• Safe Home Canning: Sorting the Evidence From the Noise
• Safe Home Canning — the reference entry
• Food Safety: The Complete Guide
• The Evidence on The Four Steps to Food Safety, Without the Hype
• Safe Internal Cooking Temperatures: What Published Guidance Supports

When to speak to a doctor

Call Poison Control at 1-800-222-1222 or your doctor if you are worried about food from a jar that may not have been canned safely. Call 911 right away for double or blurred vision, drooping eyelids, slurred speech, trouble swallowing or breathing, or muscle weakness after eating home-canned food.

Where this comes from

• USDA — Complete Guide to Home Canning
• CDC — Preventing Botulism

How this page was put together

Every figure, recommendation and warning above is taken from the guidance named in Where this comes from. Nothing on this page is inferred, summarized or generalized beyond what those bodies publish: where they give a number, it is their number, and where they are silent, so are we. Pages are rebuilt whenever the underlying record changes. Sign-off by a named clinician, where it has happened, is shown at the top of the page along with the date.

Medical disclaimer

This article is general information, not medical advice. It cannot account for your own history, medication or circumstances. Always speak to your doctor, pharmacist or another qualified health professional before making changes that affect your treatment, and never delay seeking medical advice because of something you have read here. In an emergency, call 911.