When Home Canned Food Goes Bad

Applesauce is a high acid food.
As an Amazon Associate I earn from qualifying purchases. All opinions are my own. Please see FCC disclosure for full information. Thank you for supporting this site!

Two years ago, I answered the common question of how long home-canned foods last on the shelf. In the video that accompanied this post, I said I'd do another video on what signs of spoilage to look for when you open home-canned foods. Oops. I totally forgot to do that! And since someone called me out on it recently, I thought I'd better hup-to and cover the topic.

The Best Way to Know Home Canned Food is Safe

The number one way to know home-canned food is safe is simply to follow a tested safe recipe from a modern Ball/Bernardin book, the USDA, an Extension office, or The National Center for Home Food Preservation. You can trust that your home-canned food is safe if you've used a tested safe recipe. If you get your recipe from some other source, you really have no way of knowing if it was scientifically tested for safety.

An essential part of any tested safe recipe is knowing the pH level of the food. For example, we know that fruit is high acid. This makes it considerably less likely to spoil or develop dangerous botulism. These foods are safe to water bath can.

We also know that meat and non-pickled vegetables are low acid foods, much more prone to spoilage and botulism toxin growth. They must be pressure canned, because botulism spores can't be killed until the food reaches a temperature of 240 degrees F. for a specific length of time. This is why you cannot water bath low acid foods.

Only pickled vegetables may be water bath canned.
It does not matter how long you boil low acid food or process them in a water bath canner. Boiling will not kill botulism because boiling water cannot reach 240 degrees F. In home use, only a pressure canner can do that.

Yes, the Internet is full of people who insist Grandma water bathed her vegetables and never died, but science unequivocally shows that water bathing non-pickled veggies and meat is dangerous. (I compare people who water bath low acid food to people who drive home drunk. Drunk drivers may say, "I've never been in an accident yet!" But that doesn't make driving drunk smart or safe. Someday, driving drunk will catch up with them. And sadly, the people most likely to die of botulism are the elderly and children - the people we want to protect the most.)

It is true that botulism poisoning is rare in the United States, and the CDC website allows us to see exactly how many cases there have been and what their causes were. A relatively small number of cases are caused by food, but among those cases, 38% are from improperly canned food.

The good news is, it's not the person who cans something following the Ball Blue Book who makes everyone ill. It's the person who completely throws out the rule book and cans in an egregious manner.

Three fairly recent cases of botulism poisoning caused by home canning instantly come to mind:

The first is a man who canned meat in a pressure cooker. A pressure cooker, mind you, not a pressure canner. They are not the same thing and you cannot safely can in a pressure cooker, no matter what the manufacturer says. (For more on this topic, click here.) The second strike against this guy was that he felt the processing took too long, so he shortened it. The third strike against him was that he noticed his finished jars had bulging lids - and rather than throw the food away, he decided he'd better eat the food up quickly. He nearly died of botulism poisoning.
Meat is safe to can as long as you do it right!

The second case that comes to mind involved home-canned eggs. There are no tested safe recipes for canning eggs...period. 21 people got sick from this batch of eggs, and one person died.

The third case happened just this year. A woman read online that it was perfectly safe to water bath green beans. She heard all the typical arguments in favor of this method: "Grandma used to it;" "I've done it for years and never gotten sick;" "You just have to boil it for hours;" etc. Lo and behold, she ate her water bathed green beans and became very, very ill from botulism poisoning. After recovering, she came out publicly, encouraging people to follow safe canning practices.

Remember, no one can taste, smell, or see botulism, so the best way to avoid it is to use a tested safe recipe.

How to Tell Your Home Canned Food is Bad

Of course, there are other ways food goes bad. Just like the food in your refrigerator might spoil, so can home-canned food...even when a tested safe recipe is used. However, it will only spoil if the seal on the lid of the jar fails.

Therefore, the first thing you should do when you pull a jar of home-canned food off your pantry shelf is check to be sure the lid is still tightly in place. If it comes off without any resistance, the food is almost certainly bad and the contents should be thrown away.

Even if the lid appears well sealed, when you open the jar, look for these things:

* Is the lid bulging? (If it is, do not open the jar! That food is spoiled and opening the jar may spread botulism around your kitchen.)

* Do the contents of the jar look cloudy? (Do note that if you use table salt in a recipe, it will make the contents look cloudy. That's why all tested safe recipes recommend canning salt or another type of salt that does not contain minerals or added ingredients. Otherwise, how can you know sure if the jar's contents are spoiled or if the salt is causing the cloudiness?)

* Does liquid squirt out from the jar?

* Are the contents slimy?

* Is the food fermented? (Canned food should not ferment. If it does, it's a sign the food is spoiled and could make you very ill.)

* Does the food smell weird?

* Is there yeast on the food?

* Is their mold?

Beans are low acid and require pressure canning.
Once upon a time, everyone believed you could just scrape mold off high acid foods, like jam. Now we know that even though the food might not make you feel ill, consuming mold spores can have adverse health effects.

Experts also used to say that if you suspected food had spoiled, you could just boil it for ten minutes and then safely eat it. But remember, botulism can't be killed by boiling, so this is no longer recommended.

How to Safely Dispose of Spoiled Home Canned Food

What should you do in the unlikely event your home-canned food spoils? If the food is high acid (fruit), you may toss the contents of the jar in your garbage can, just like you would spoiled food from your refrigerator. But if the food is low acid (meat and non-pickled vegetables), you should take additional precautions to avoid spreading botulism all over your kitchen.

1. Put on rubber or latex gloves.

2. Place the jar with the food still in it (include the jar lid, too) in a kitchen bag. Tie off the kitchen bag, then tape the top closed. (You want to ensure botulism stays in the bag.)

Do NOT pour the food out of the jar, because this can potentially spread botulism in the immediate area, as can washing a jar that had botulism-spoiled food in it.

3. Use bleach to clean anything the jar touched, like your counter or pantry shelf. Let the bleach sit for 20 minutes before washing away.

4. Toss any towels or sponges you used in the cleanup, as well as your gloves, in another kitchen bag. Tie off the bag and seal it shut with tape.

5. Dispose of the bags in your garbage can.

1 comment

  1. Wow! I'm one of those women who were taught to water bath process carrots and green beans - boil for THREE HOURS! And I DID that for several years.
    I eventually got a pressure canner for myself AND for the precious friend who innocently taught me the wrong way. Now I'm learning even more about what to do with canned goods that have gone bad, because now it's my turn to turn around and teach a new generation how to grow and preserve our food.