food-preservationfood-safetypackagingstoragestorage-method
How does package food producers such as "Seeds of Change" or "Pacific Foods" package their food to keep for up to 15 months and store without refrigeration? What consumer, or DIY approach, most closely resembles their process?
It seems they use certain natural preservatives, detailed packaging materials, a food vacuum system, and perhaps a bit of drying. I'm trying to avoid canning if possible. The plastic/paper material weighs a lot less.
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].
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.
| 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] |
| 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] |
| 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] |
| 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.
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] |
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.
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.
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.
| 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] |
| 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] |
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.
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.
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.
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.
Best Answer
The commonest (in my experience - probably variable around the world) consumer DIY approach to this is the one that uses the step that you missed - high temperature (as mentioned by @John Feltz) - namely, pressure canning at 15 PSI (250°F) - in my experience, glass canning jars with metal lids, but flexible packages are evidently consumer-available more commonly that I've seen them around the world (perhaps even here, if I was looking for them.)
I've certainly eaten canned items stored at room temperature well older than 15 months and lived to tell the tale - indeed, I don't consider it anything to think about, other than verifying that the jar is, in fact, still sealed when time comes to use it. This may well not coincide with the most-paranoid recommendations on canned food shelf-life, but surely someone will be along to give the most-paranoid view shortly.