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Extension > Food > Food Safety > Preserving and Preparing > Canning > Canning Basics 9: Storing Canned Food

Canning

Canning Basics 9: Storing Canned Foods

William Schafer, Food Technologist — Department of Food Science and Nutrition

Reviewed 2012 by Suzanne Driessen, Extension Educator — Food Safety.

Storing Canned Foods

If lids are tightly vacuum sealed on cooled jars, remove screw bands, wash the lid and jar to remove food residue, then rinse and dry jars. Label and date the jars and store them in a clean, cool, dark, dry place. Do not store jars above 95°F or near hot pipes, a range, a furnace, in an uninsulated attic, or in direct sunlight. Under these conditions, food will lose quality in a few weeks or months and may spoil. Dampness may corrode metal lids, break seals, and allow recontamination and spoilage.

Accidental freezing of canned foods will not cause spoilage unless jars become unsealed and recontaminated. However, freezing and thawing may soften food. If jars must be stored where they may freeze, wrap them in newspapers, place them in heavy cartons, and cover with more newspapers and blankets.

Identifying and Handling Spoiled Canned Foods

Do not taste food from a jar with an unsealed lid or food which shows signs of spoilage. You can more easily detect some types of spoilage in jars stored without screw bands. Growth of spoilage bacteria and yeast produces gas which pressurizes the food, swells lids, and breaks jar seals. As each stored jar is selected for use, examine its lid for tightness and vacuum. Lids with concave centers have good seals. Next, while holding the jar upright at eye level, rotate the jar and examine its outside surface for streaks of dried food originating at the top of the jar. Look at the contents for rising air bubbles and unnatural color.

While opening the jar, smell for unnatural odors and look for spurting liquid and cotton-like mold growth (white, blue, black, or green) on the top food surface and underside of lid.

Carefully discard any jar of spoiled food to prevent possible illness to you, your family, and pets. You must detoxify the container, lid, and all the contents before disposal. To do so, place container with contents and lid on their sides in an 8-quart or larger stock pot, pan, or boiling-water canner. Wash your hands thoroughly. Add water to the pot so it is 1 inch or more above everything in the pot. Avoid splashing the water. Place a lid on the pot and heat the water to boiling. Boil 30 minutes to ensure detoxification of the food, container, and lids. Cool and discard the food, container, and all container components such as lids in the trash or bury in soil. Take care that animals or children cannot get in contact with the disposed food and containers. Thoroughly wash all counters, containers, and equipment including can opener, clothing, and hands that may have been in contact with the food or containers. Discard any sponges or wash cloths used in cleaning. Place all in a plastic bag and discard in the trash where they are unreachable by animals and children. This will prevent accidental poisoning.

Amount You Should Can

The amount of food to can or freeze for your family should be decided by your family. The following formula might be helpful in calculating your needs.

Use the suggested serving size for a particular food as listed below. Multiply this amount by the number of family members who will be eating this food. Then multiply this by your estimate of the number of servings per week per person. Multiply this figure by 52 weeks to get a total amount necessary to preserve in one year. To get this amount in quarts, multiply the number by four.

Example:
Fruit—½ cup suggested serving X 4 family members = 2 cups.
Two cups X 3 servings per week per person = 6 cups/week.
Six cups X 52 weeks/year = 312 cups.
Divided by 4 = 78 quarts.

Suggested serving sizes
Fruits½ cup
Juices1 cup
Vegetables½ cup
Meat and seafood½ cup
Soups1 cup
Sauces½ cup
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