Home Canning Safety Tips

Reviewed by Sarah Klemm, RD, CD
home canning

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How do you like your vegetables? If you are among one of the many households in the United States who preserve their own food, then chances are you enjoy homegrown vegetables fresh from your own canning jar. You may be part of a growing segment of Americans who are returning to the "farm your own food" way of life to cut food costs and eat healthfully.

Part of the "farm your own food" philosophy is preserving what you grow. Food that is properly canned and kept in a cool, dry environment will last for at least one year. Home canning is affordable and trendy, but can be deadly if proper safety precautions are not taken during the canning process.

From 1996 to 2014, 30 percent of foodborne botulism outbreaks reported to the Centers for Disease Control and Prevention were from home-canned vegetables. Botulism is a rare but serious illness caused by a germ called Clostridium botulinum, found in soil. The germ can multiply and produce toxins in improperly canned food. Here are some helpful guidelines to help prevent this devastating germ from ruining your food.

Home Canning the Safe Way

  • Follow USDA-approved modern canning methods. You might be using the same recipes passed down through generations of family members but make sure your canning methods are up to date. Canning methods and equipment have improved food safety over time. Follow current guidelines from the U.S. Department of Agriculture's Complete Guide to Home Canning or your state County Extension Service.
  • Use a pressure canner. The acidity of foods adds extra protection when preserving them. Most fruits contain enough acid that they can be preserved by hot water canning – a method of boiling the prepared, sealed jar in water. Other foods, such as vegetables and meats, have a much lower acidity, which puts them at risk for botulism. For low-acid foods, pressure canning is the only method to kill the germ that causes botulism. It helps the contents of the jar reach a higher temperature than boiling alone. This higher temperature is essential for destroying botulism spores.
  • Add acidity to tomatoes. The natural acidity of tomatoes can vary. While some varieties are acidic, others are actually considered a low-acid food. Be sure to add lemon juice or citric acid to the mixture to help keep it safe, especially if you’re using hot water canning!

Pick the Right Pressure Canner

  • Select a pressure canner big enough to hold at least four quart jars; the USDA does not recommend pressure canners smaller than this size.
  • Use canners with the Underwriter's Laboratory, or UL, approval to confirm their safety.
  • Safeguard your canning process by making sure the canner is in good working condition.
  • Check all openings for cleanliness.
  • Examine the rubber gasket provided with some brands of pressure canners. The gasket should be flexible and soft, not brittle, sticky or cracked.
  • Understand altitude adjustments during processing; printed procedures should be with the manufacturer's instructions.

Step-by-step procedures for proper use of pressure canners are described in Preserving Food: Using Pressure Canners.

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