Downright unsafe canning methods

Avoid these unsafe canning methods to help preserve food safely. Just because it seals doesn’t mean it’s safe.

Home canning can be a fun, inexpensive and convenient way to store food for future use. However, canned food can be safe or unsafe depending on how it is preserved. Preserve your food safely by using research-based preserving methods.

There are five safe methods for preserving food safely at home: water bath canning, pressure canning, steam canning, freezing and dehydrating.

Do not confuse steam canning with steam pressure canning. New research on steam canning states that an atmospheric steam canner is safe to use for preserving high-acid foods such as fruit, pickles and acidified tomatoes. Steam canning uses a covered, shallow pan and rack to circulate steam around filled jars. Steam in this type of canner is not pressurized. Steam canners should never be used for low-acid foods, such as vegetables and meats, that need to be pressure canned to be safe. 

Unfortunately, there are also several unsafe canning methods

Never use any of the following methods

Don't try oven canning— Oven canning is extremely dangerous.

  • Jars may explode when the oven door is opened.
  • You or anyone nearby can be seriously cut or burned when the jars explode.
  • Your oven can sustain serious damage when jars explode.
  • There is no reliable research-based information as to how long or what oven temperature to use.

Don't try dishwasher canning - There is no way to control the temperature or processing time in a dishwasher. Even at its hottest setting the temperature of the water during the cleaning and rinsing cycle is way below the temperature needed to kill harmful bacteria.

Don't try open kettle canning - This method is also known as cold packing and no matter what you call it this way of canning is not recommended. With open kettle canning, food is first cooked in a pan and then put into jars. The lids are quickly put in place and no further processing takes place. The jars may seal but bacteria can easily survive and multiply inside the sealed jar and then cause the canned food to spoil quickly or cause illness when eaten.

Don't try microwave canning - Different microwave ovens have different heating properties and there are no standards for controlling internal temperatures of any canned product. 

Don't try solar canning - Sunshine is a wonderful thing but that beautiful sunshine should never be used to can food.

Make sure your canning techniques are up to date. Just because it seals doesn’t mean it’s safe! Michigan State University Extension encourages safe home food canning methods using only research-based information from the National Center for Food Preservation, USDA, recent Ball Blue books or Extension Services.

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