Safe methods for canning and garden produce preservation for novices

CoMMentary

If you’re anything like me, the COVID-19 pandemic has left you with a lot of extra time around the house. For me and many others, this has meant diving into hobbies such as gardening. 

This is a new hobby for me and as everything is seemingly ripening at the same time, I’m searching for ways to safely preserve my produce before it spoils.

Here are some useful safety tips and resources I’ve found helpful:

Home canning is an excellent way to preserve your garden produce, but if home canning is not done the proper way, your canned vegetables and fruits could cause botulism.

Botulism is a rare but potentially deadly illness caused by a poison most commonly produced by a germ called Clostridium botulinum. The germ is found in soil and can survive, grow, and produce a toxin in certain conditions, such as when food is improperly canned. The toxin can affect your nerves, paralyze you, and even cause death.

You cannot see, smell, or taste botulinum toxin—but taking even a small taste of food containing this toxin can be deadly.

Botulism is a medical emergency. If you or someone you know has symptoms of foodborne botulism, see your doctor or go to the emergency room immediately.

Symptoms may include the following:

• Double vision
• Blurred vision
• Drooping eyelids
• Slurred speech
• Difficulty swallowing
• A thick-feeling tongue
• Dry mouth
• Muscle weakness

Safe canning tips from the Centers for Disease Control and Prevention

Many cases of foodborne botulism happen after people eat home-canned, preserved, or fermented foods that were contaminated with toxin. The foods became contaminated because they were not canned correctly.

1. Use proper canning techniques.

The best way to prevent foodborne botulism is by carefully following instructions for safe home canning in the USDA Complete Guide to Home Canning. 

Do not follow recipes and cookbooks that do not follow the steps in the USDA guide, even if you got these items from a trusted friend or family member.

You can learn more about proper home canning from these resources:

• The National Center for Home Food Preservation
• State and county extension services

2. Use the right equipment for the kind of foods that you are canning.

Pressure canning is the only recommended method for canning low-acid foods. Foods with low acid content are the most common sources of home-canning related botulism cases. Low-acids foods include almost every vegetable, some fruits, milk, all meats, fish, and seafood. See box to the right for examples. Do not use boiling water canners for low-acid foods because they will not protect against botulism.

What is low-acid food?

Low-acid foods have a pH level greater than 4.6, which means they are not acidic enough to prevent the growth of botulinum bacteria. Examples are:

• Asparagus
• Green beans
• Beets
• Corn
• Potatoes
• Some tomatoes
• Figs
• All meats
• Fish and seafood

Always use a properly sized pressure canner that meets USDA recommendations for pressure canning when canning low-acid foods. Contact your state or county extension service to find out if your pressure canner meets USDA recommendations.

3. When in doubt, throw it out.

If there is any doubt if safe canning guidelines have been followed, do not eat the food. Home-canned and store-bought food might be contaminated with toxin or other harmful germs if

• the container is leaking, bulging, or swollen;
• the container looks damaged, cracked, or abnormal;
• the container spurts liquid or foam when opened;
• the food is discolored, moldy, or smells bad.

If the container or the food inside has any signs of contamination, throw it out! If any of the food spills, wipe up the spill using a solution of 1/4 cup bleach for each 2 cups of water.

Never taste food to determine if it is safe. Do not taste or eat food that is discolored, moldy, or smells bad. Do not taste or eat food from cans that are leaking, have bulges or are swollen, or look damaged, cracked, or abnormal. Do not taste or eat food from a can that spurted liquid or foam when it was opened.

University Extensions

There are many universities that offer extension programs that teach community members about safe canning and food preservation. 

Utah State University’s Preserve the Harvest extension is one that I have found to be helpful. USU’s extension offers an online lecture series on preserving your garden harvest, as well as an online canning course. 

Other resources on the page include information and instruction on: 

• Selection, preparation, and pretreating of foods
• Canning
• Freezing
• Drying
• Food storage and packaging

Iowa State University is another institution offering free instructional courses on food preservation.

ISU’s Food Preservation 101 is a one-hour online course.  During which, nutrition and wellness specialists will:

• Discuss various food preservation techniques – pressure canning, hot water bath canning, dehydration and freezing.
• Provide science-based, reliable food preservation resources.
•  Answer general food preservation questions.

Food Preservation 101 will be hosted numerous dates and times between May and September.

For more information and to register, visit their website.

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