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How do I know if a given food or ingredient I have is still good, or if I should discard it?

How can I best preserve a food or ingredient?

This broad question is intended as a "general reference" question to quickly answer many how long will food keep for? questions. Please feel free to edit this question to expand and clarify as needed.

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General comments on the shelf-, fridge-, and freezer-life of foods

The shelf-life is the amount of time a food can be stored before it is considered unsuitable for use. It may be unsuitable due to quality degradation (no longer tasty) or food safety (risk of food poisoning). [1]

As far as food safety goes, food stored frozen at 0°F (-18°C) or below is remains safe forever; only quality degrades over time. [2]. Thus the freezer-storage times below are entirely about quality. This temperature should be maintained fairly closely (within 3°C[6] or 5°F) and a defrost / no-frost freezer should not heat air surrounding the products by enough to heat the products more than that.

If your freezer is set at a temperature higher than -18°C (three-star setting), these times may not apply. Especially the safe storage time in one-star freezers (-6°C) is much reduced.

The times all assume proper storage. Freezers 0°F or below, refrigerators 40°F (4°C) or below. [3] Cans should be stored in a cool, dry place, below 85°F (30°C) [4]. The freezer itself should also be placed correctly: if the environmental temperature drops below 10°C (50°F), oil might be too viscous and work less well or damage the compressor[7], so please refer to the operating manual before deciding on an unheated garage.

The tables given here assume proper storage. Food which requires refrigeration is considered unsafe if left for over two hours at temperatures between 41–135°F (5–57°C) [5].

The Tables

Regardless of the table below, if a food shows signs of spoilage (including mold, with some exceptions described below), its past its shelf-life. Note that the lack of spoilage does not imply safety.

Uncooked Proteins

Item Fridge Freezer Sources
Ground (meat, poultry) 1–2 days 3–4 months [KC]
Non-ground meat 3–5 days steaks: 6–12 months
chops: 4–6 months
roasts: 4–12 months
[KC]
Poultry 1–2 days whole: 12 months
pieces: 9 months
[KC]
Eggs in shell: 3–5 weeks
separated: 2–4 days
in shell: not recommended
whites: 12 months
yolks: not recommended
[KC]
Bacon 1 week 1 month [CFG]
tofu 1 week 5 months [CFG]
fish 1–2 days lean: 4–8 months
fatty: 2–3 months
[CFG]

Cooked proteins

Item Fridge Freezer Sources
luncheon meat opened: 1 week
unopened: 2 weeks
1–2 months [KC]
cooked meat and poultry 3–4 days 2–6 months [KC]
cooked fish 3–4 days 1–2 months [CFG]
hard boiled eggs 1 week not recommended [KC]
hard sausage 2–3 weeks 1–2 months [CFG]

Dairy

Item Fridge Freezer Sources
butter 1–3 months 6–9 months [CFG]
hard cheeses opened: 3–4 weeks
unopened: 6 months
6 months [CFG]
soft cheeses 1 week 6 months [CFG]
cream cheese 2 weeks not recommended [CFG]

Sauces

Item Fridge Freezer Sources
mayo commercial: 2 months
home-made: see below
not recommended [CFG]
gravy, broth 3–4 days 2–3 months [CFG]

For home-made mayo, there don't seem to be official shelf-life estimates. Seasoned Advice has a question on this, Making "long(er)-life" homemade mayonnaise.

Vegetables

Freezer times are given for cooked or blanched, then frozen. Generally, this is required, otherwise enzymatic degradation will occur. See "Where can I go for details on a specific food?" for where to find specific steps for each vegetable.

Refrigerator and shelf times are for storage raw.

If a column is -, it means that storage type is not recommended. "Ripe" means "until ripe".

Item Shelf Fridge Freezer Sources
Asparagus - 3–4 days 8 months [FK]
Green beans - 3–4 days 8 months [FK]
Beets 1 day 7–10 days 6–8 months [FK]
Cabbage - 1–2 weeks 10–12 months [FK]
Carrots - 3 weeks 10–12 months [FK]
Celery - 1–2 weeks 10–12 months [FK]
Garlic 1 month 1–2 weeks 1 month [FK]
Herbs (fresh) - 7–10 days 1–2 months [FK]
Lettuce (iceberg) - 1–2 weeks - [FK]
Lettuce (leaf) - 3–7 days - [FK]
Mushrooms - 2–3 days 10–12 months [FK]
Onions, non-sweet 2–3 months 2–3 months 10–12 months [ST]
Onions, sweet 1–2 months 1–2 months 10–12 months [ST]
Peppers - 4–5 days 6–8 months [FK]
Potatoes 1–2 months 1–2 weeks mashed: 10–12 months [FK]
Squash, summer - 4–5 days 10–12 months [FK]
Squash, winter 1 week 2 weeks 10–12 months [FK]
Tomatoes ripe 2–3 days 2 months [FK]

Fruits

Many fruits must be at least partially cooked (blanched) before freezing in order to deactivate enzymes that would otherwise degrade quality while in storage. Some are best frozen packed in acid (lemon juice or citric acid) and/or syrup. See "Where can I go for details on a specific food?" for where to find specific steps for each fruit.

If a column is -, it means that storage type is not recommended. "Ripe" means "until ripe".

Item Shelf Fridge Freezer Sources
apples 1–2 days 1–3 weeks cooked: 8 months [FSG], [FK]
apricots ripe 2–3 days - [FK]
bananas ripe 1–2 days* peeled: 1 month [FK]
berries - 1–2 days 4 months [FSG], [FK]
citrus fruit 10 days 3 weeks - [FSG]
grapes 1 day 1 week 1 month [FK]
juice - 6 days 8 months [FSG]
melons 1–2 days 1 week balls: 1 month [FSG], [FK]
generally: 3-5 days

*: bananas stored in the fridge will blacken. This is not a sign of spoilage, and they can be eaten safely.

Cooked dishes

2 hours on the counter, for all of them, unless you prepared a known shelf-stable item which generally does not go in the fridge (like cookies, or a canned jam, or others). It does not matter how long the individual components would have lasted on their own.

Refrigerated: generally 3–4 days in the fridge. This includes pizza, soups, stews, casseroles, pies, and quiche [KC]. Some salads get a fifth day [CFG]. Freezer time is generally under three months.

Infused oils

Putting any plant matter in oil (such as garlic, chillies or herbs) creates the danger for botulism, a rare but fatal disease. Thus infused oils are not shelf-stable. They can be kept in the refrigerator for 3-5 days, discard them earlier if you see cloudiness or gas bubbles. Or buy commercially produced infused oils, they have been treated with industrial methods to kill the botulinum spores.

Shelf-stable until opened

Item Unopened Opened, in fridge Source
Commercially canned, low-acid (meat, poultry, fish, soups, stews, vegetables) 2–5 years 3–4 days [CFG]
Commercially canned, high-acid 12–18 months 5–7 days [CFG]
Olives 12–18 months 2 weeks [FK]
jam, jelly, preserves 1 year 6 months [FK]
shortening (Crisco) 8 months 3 months [FK]

Pantry (not refrigerated even after opening)

Item Shelf life opened (if different) Source
Baking powder 18 months [FSG]
Baking soda 2 years [FSG]
beans (dry) 1 year [FK]
Bouillon 1 year [FSG]
cornstarch 18 months [FK]
extracts 3 years [FK]
flour white: 6–12 months
wheat: 1 month
[FK]
herbs (dry) 1–2 years 1 year [FK]
honey 1 year [FK]
pasta (dry) 2 years [FSG]
egg noodles (dry) 6 months [FSG]
rice (dry) white: 2 years
brown: 6–12 months
flavored: 6 months
[FSG]
vegetable oil 6 months 1–3 months [FSG]
vinegar 2 years 12 months [FSG]

General tips for storing foods

How do I freeze fruits and vegetables?

Fruit. Ripe (but not overripe) fruit should be used. Wash them, and sort according to size. Working in small batches, remove pits, seeds, and blemishes. For fruits that turn brown, apply ascorbic acid or sugar and citric acid. Most fruits benefit from packing in dry sugar or a sugar syrup. Small, whole fruits (e.g., berries) can be spread on a tray and individually frozen, then packed in a freezer bag or other airtight container.

Vegetables. Most vegetables need blanching. To blanch, immerse in boiling water over high heat or steam over rapidly boiling water (steam). After blanching, transfer to ice bath for the same amount of time as blanched. Drain and dry. Freeze either by packing in a freezer bag with as much air as possible removed, or by allowing to freeze on a tray, then putting in a bag or other container.

General guideline is 8–12 months for best quality.

The above is a very quick summary of Iowa State University's Preserve the Taste of Summer: Freezing: Fruits and Vegetables. The five-page document includes full details on over forty fruits and vegetables. Feel free to ask here on Seasoned Advice if that guide doesn't answer your question.

What about mold?

Some foods are expected to have mold in them (e.g., P. roqueforti in Roquefort cheese). Unexpected mold, however, is something to be concerned about. Mold can grow even on refrigerated foods, and even those high enough in salt or sugar to deter bacteria. Some molds produce mycotoxins. Mold growth can be minimized by cleaning the refrigerator every few months (use a mixture of 1 tablespoon of baking soda per quart of water, then rinse with plain water, then dry), by keeping dishcloths, sponges, mops, etc. clean and fresh-smelling; and keeping indoor humidity levels under 40%.

In general, the visible surface mold on a food is only a small part of the actual mold growth. For most foods, any visible unexpected mold growth means you should discard the entire item. There are several exceptions:

Food How to handle mold
Hard salami, dry-cured country hams Scrub mold off surface.
Hard cheese Cut at least 1 inch around and below mold spot, do not cut through mold.
Cabbage, bell peppers, carrots Cut at least 1 inch around and below mold spot, do not cut through mold.

Everything else, including soft or shredded cheese, soft fruits and vegetables, bread, peanut butter, jams and jellies, sour cream, yogurt, luncheon meats, casseroles, and cooked pasta should be discarded.

All this information comes from the USDA FS&IS's Molds on Food: Are They Dangerous? fact sheet.

Where can I go for details on a specific food?

The web site StillTasty maintains a comprehensive list of food storage times, notes, and procedures for a wide variety of food items. They draw information from a variety of reputable sources and should probably be the first place you check.

Another good source of information is the Food Marketing Institute's Food Keeper. This is also a searchable database of foods.

Finally, if neither of those two references answer your question, you're at the right web site. Please ask here on Seasoned Advice.

Bibliography

Note

This is a work-in-progress. I still need to finish adding information to it. Also, this answer is a community wiki, please feel free to improve it.

  • For printing, I've copypasted this text and edited the tables. How and where can I upload the file so it's available to the community? – BaffledCook Feb 12 '12 at 8:37
  • @BaffledCook: Not sure where to upload it. If your versions of the tables are just better, then I guess just edit the question. Otherwise, there are always things like pastebin (though I have no idea how to keep the two versions in sync, then). Maybe ask on meta? – derobert Feb 12 '12 at 10:25
  • I'll ask on Meta. I made a LibreOffice doc. Syncing (?) will be hell. – BaffledCook Feb 12 '12 at 10:52
  • You might add that mold on real maple syrup (not maple flavord corn syrup) can be removed, and the syrup still used. – Flimzy May 10 '13 at 22:56
  • 1
    The USDA's guideline on eggs in the fridge is extremely conservative, more so than most of the items on this list. – WetlabStudent Apr 30 '15 at 16:53

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