Well, here it is February — Canned Food Month! A good time, I suppose, to answer some questions about how to store canned foods safely. (I like spending the slower winter months learning about homemaking, organizing indoors, nesting, and the like. So the canned food marketers timed this perfectly for me!)
These tips and answers about storing canned foods apply to both foods you’ve canned yourself and cans from your local grocer. (Some of these answers surprised me! I’m sure I learned in Home Ec class 50 years ago that eating food out of an opened can in the refrigerator would be fatal!)
BTW, if you have shelves of home-canned fruits, veggies, sauces, and pickles, I’m seriously jealous — I mean happy for you. I don’t enjoy canning, but all those beautiful jars of food lining a pantry make me swoon.
How long can I safely keep canned goods?
For best quality, use canned goods within a year. If the cans and food look okay, the food is still safe to eat after that, but it may not taste as good or be as nutritious. Low-acid foods, such as vegetables and most soups, will last longer than high-acid foods, such as tomatoes and pickles.
If quality isn’t a consideration, canned foods are usually safe to eat for two to three years. If you store a lot of canned foods, rotate your stock so you use up the oldest cans first.
Why do canned goods stay safe so long?
Heat processing the cans destroys microorganisms and inactivates enzymes. When the food cools, an airtight vacuum seal forms to prevent any new bacteria from getting in the jar or can.
Even with processing, though, the food won’t keep forever. That’s because cans (and lids on glass jars) can rust over time, causing spoilage.
Of course, as soon as you open a can, you’ll need to refrigerate the food to prevent the growth of bacteria.
Where should I store canned foods?
Find a cool, dark, dry place for your canned goods. Moisture can corrode the cans, so don’t store them in a moist place, like a damp basement. In glass jars, the moisture can corrode the lids and break seals. Any of this can lead to spoilage.
Aim for temps between 50 and 70 degrees F. Definitely keep the cans or jars from freezing, and make sure they don’t get too hot. Storing cans for prolonged periods above 75 degrees F decreases nutritional value. And when temperatures climb to over 100 degrees F, the risk of spoilage skyrockets. (In fact, canned foods processed for tropical areas are specially manufactured to protect against the high temps.)
So make sure you don’t store canned foods near a heat source, such as a stove or furnace, and keep them out of direct sunlight. If you need to store them in an area that might get too cold, wrap them in newspaper, tuck them in boxes, and cover them with blankets.
How will I know if a can of food is spoiled?
Look for these telltale signs:
• Bulging jar lids or bulging cans. Food produces a gas as it rots and grows mold, and that gas causes the bulging.
• Leaking cans. If a can is leaking, it means there’s a place that’s been exposed to air, which can allow contamination of the contents.
• Badly dented cans. (See below.)
• Food that smells bad. Anything from a slightly off odor to a repelling smell means the food is tainted.
• Mold growth when you remove the lid. If you see mold spores on the inside of the lid or around the rim, the entire contents are not safe to eat.
Don’t taste food to determine if it’s good to eat. Even microscopic amounts of botulism spores, for example, can make you extremely sick.
What’s the best way to prepare home-canned foods for storage?
• After processing, test the seals. They shouldn’t pop or buckle when you press on the center of the lid with your finger.
• Remove the screw bands and wash, rinse, and dry the jar. (Be careful not to disturb the seal on the sealed lid.) Any remaining food residues can grow mold outside the jar. Eww.
• Label and date each jar.
• If you stack jars, be careful you don’t break the vacuum seals. In fact, it’s better not to stack them at all. If space makes it necessary, place a board over a row of jars, and then stack the next row on top of the board.
• Store jars upright. Food settles to the lowest point, and the pressure on the lid can weaken the seal. Also, if acidic contents come in contact with the seal, it can corrode the metal lid and cause spoilage.
For more information on how to can everything from fruits to meats and salsa, visit the National Center for Home Food Preservation.
Is it okay to purchase dented cans of food?
Not if the dents are big — and especially if they’re on the seam or trim. Little dents are okay, but larger dents (one you can lay your finger into, or one that has sharp points) can break the seal that keeps bacteria from contaminating your food.
So when you see dented cans on sale at the grocers, pass them up unless they’re little dents. Even then, don’t store them for a long time; put them on the menu soon!
Is it okay to store food in the refrigerator in an opened can?
It’s not dangerous, but for best flavor, it’s better to transfer the food to a sealed storage container. Especially with highly acidic foods like tomatoes, the food can absorb the coating of the can, resulting in an off taste. The food can also spoil more quickly if exposed to air (if you don’t cover the can).
Can I put unopened canned food in the freezer?
No, the can is likely to burst when any liquid inside freezes and expands. Store canned goods in a cupboard or pantry. After opening a can, you can put the food in a clean container and store it in the refrigerator or freezer.
Is it safe to use canned food that accidentally freezes?
If you handle it safely, yes.
Here’s how the USDA says to safely save the contents: If the can is still frozen, put it in the refrigerator to defrost it. Open it after it defrosts and examine the food. If it doesn’t look and smell fine, discard it.
If it looks and smells normal, then boil the food for 10 to 20 minutes (10 minutes at altitudes below 1,000 feet and an additional minute for each additional 1,000 feet elevation. Because they are dense, boil spinach and corn for 20 minutes at all elevations.) You can then serve the food or put it in a fresh, clean container and refrigerate or freeze it for later use.
Never eat canned food that was frozen and then thawed at room temperature!
Should I throw away rusted cans?
If there’s just a little surface rust on the can that you can easily wipe off with your finger or a towel, it’s okay to keep the can, according to the USDA. Discard a can that’s heavily rusted, though. A rusted can might have tiny holes in it, which can allow bacteria to enter the contents. If you see rust inside any can when you open it, don’t eat the food; discard it.
Do you have other questions about storing canned foods? Let us know! And I’d love to swoon over your pics of home-canned goods!