How Long Does Canned Food Last?

The USDA gives two working numbers for unopened commercial tins kept in a cool, dry place:

• High-acid foods such as tomatoes, most fruit, fruit juice, pickles and sauerkraut: 12 to 18 months.
• Low-acid foods such as meat, poultry, fish, most vegetables, beans, pasta dishes and soups (other than tomato): 2 to 5 years.

Those are quality guides, not cliff edges. The USDA says high-acid tins keep 12 to 18 months and low-acid tins two to five years beyond their printed dates, as long as the can is in good condition and stored somewhere cool, clean and dry. Home-canned food is different: use within a year.

Acid is what protects the food, and it is also what slowly attacks the inside of the can. In tomatoes and citrus, the food reacts with the metal over the years, which can change taste and texture and gradually lower the nutritional value. That is why tomatoes and fruit have the shorter shelf life. Low-acid foods are heat-processed harder for safety, and react less with the tin, so they last longer.

The best storage temperature for tins is about 50 to 70 F (10 to 21 C). Clemson's extension service notes that storage time drops significantly above 75 F (24 C). The USDA suggests staying below 85 F (29 C) and warns that temperatures above 100 F (38 C) are harmful.

So do not store tins above the cooker, next to a boiler, under the sink, in a hot loft or in a damp garage. A cupboard on an interior wall is usually best. Damp is a problem as well, because it rusts tin and lids.

Bin the tin, without tasting, if it is:

• bulging or swollen at either end,
• leaking or sticky,
• badly rusted, especially along the seams,
• deeply dented, particularly on the seam or rim,
• spurting liquid when opened or smelling wrong.

A small dent in the side of a tin that is otherwise sound is usually cosmetic. Anything that looks like the seal might be compromised is not worth the risk. Never taste food to see if it is safe. Once opened, move the contents to a covered container in the fridge and use within a few days, depending on the food.

There are two main types of date. A use-by date is a safety date on perishable food and should be followed. A best-before or best if used by date on shelf-stable food is about quality. The USDA says shelf-stable food is safe past that date if the container is sound and it has been stored properly, but it may lose some flavour or texture.

Check the base of the tin, where many manufacturers print the date, and copy it onto the lid in marker so you can read it on the shelf. If there is a code you cannot read, write the date you bought it and treat it as a year old for tomatoes and fruit, or three years old for meat and vegetables.

Figures come from the USDA FSIS shelf-stable food page, the USDA pantry checklist, Clemson Home and Garden Information Center and NDSU Extension.