How Long Does Dehydrated or Freeze-Dried Food Last After Opening?

· Reading Time: 3 minutes

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There are a few factors that determine how long food will last after it is opened. They include the following:

  • The quality of the food at the time it is opened
  • The degree to which food is exposed to oxygen and moisture
  • The degree to which food is exposed to heat and light


The quality of the food at the time it is opened:

The older food storage gets and the more it is subjected to fluctuating temperatures (meaning below freezing and above 80 degrees), the more deterioration has probably occurred to the food inside the container.

The degree to which food is exposed to oxygen and moisture:

The moment the container is opened, the food is exposed to air. Air contains both oxygen and moisture. Many organisms require oxygen to survive. The higher the humidity (moisture content) of the air, the faster the product quality (nutrition and taste) deteriorates.

The degree to which food is exposed to heat and light:

Temperature greatly affects the speed at which food deteriorates. The higher the temperature is, the faster the quality (nutrition and taste) deteriorates and the shorter the time that food stays edible and safe. Since many organisms require light to grow, exposure to light also causes deterioration.



Once you have opened your food storage, you can prolong its shelf life by eliminating the adverse affects listed above. Store your food in the coolest, darkest and most airtight environment possible.

Consider the following options to extend the life of food, once the container has been opened.

  • Pour what has not been used into a zip-top freezer bag and seal the bag. Place the bagged food back into the can and replace the lid (to eliminate light).
  • Pour the remaining food into Snapware® containers, which offer an airtight seal.
  • Commercially available sealers can create an airtight environment. Put the food back into the can with the plastic lid secured.
  • Generally speaking, refrigeration or frozen storage can extend the life of food. If you do not have much refrigeration or frozen storage space, use a pantry, cupboard, etc.

As a general rule, food stored in a #10 can or a bucket, depending on the above factors, may stay good up to one year after opening. Use your best judgment in deciding which food items to use. One way to determine if food is still of acceptable quality is to verify that it smells normal. Another way is to taste it or cook with it. If the quality of the finished product is satisfactory, continue to use it. Although food will lose nutritive value over time, old food retains some caloric and mineral value. It may have some life sustaining nutrients remaining.

The information above are general guidelines intended to help make an educated decision. Each situation is unique due to many contributing factors.

22 Responses

  • So would you suggest after putting the food in a freezer bag and sealing it putting it in the freezer? I would say yes so I am probably answering my own question. We have opened some cans recently that were over 25 years old and what we have opened so far has been good.

  • That would be a great idea to put it in your freezer. Remember that temperature is one factor in how long your food will last after opening. You want to store it as cool as possible, so a freezer is a great way to accomplish that. Some other options would be a refrigerator or in a cool basement.

  • Concerning freeze-dried cheese specifically, how long will it remain safely edible after opening if not refrigerated or frozen? I'm a long-distance hiker and want to save weight with f-d foods. I have used your f-d meats, veggies, and fruits w/out a problem, but I'm not sure about the cheeses. Thanks in advance. JDM

  • The information and concepts in this post can be applied to all the different types of dehydrated and freeze-dried foods. Simply treat cheese as you would meats or veggies or fruits. Without being refrigerated or frozen (for example while hiking), it could last up to 3 months if not exposed to extreme temperatures or humidity. Happy Trails!

  • Thanks for the prompt reply. Part of my next trip includes the So Cal desert, with likely high temps. Should I avoid f-d cheese thru that section? Or is the safe time reduced to a day? A week? A month? Any guidance is welcome. And by the way, would PP like to sponsor a PCT hiker? Publicity and endorsements in exchange for free food? Thanks again, JDM

  • Temperature is a major factor in the shelf life of any item, including freeze-dried cheese. I would not specifically avoid any one product, the general guidelines which we have outlined is for all products. Unfortunately, we do not have the answer to your question regarding how long any specific item will remain safe. Please feel free to email any request to Thank you!

  • If you open a large container and know that you will not use the rest up for a while, you could also share it out into jars with oxygen absorbers or canning jars sealed with you sealameal.

  • Are there any #10 can items that have a particularly short shelf life once opened? Meats? Powdered eggs? Butter?

    I'm thinking about getting some powdered eggs for baking with (muffins, etc.) but I am unsure about the specific shelf life, as it might take me a while to use up the whole can.

    I live in the south. I have a cool, dark walk-in pantry that ranges between 65-80*F. I have limited refrigerator space, but I have a chest freezer and usually have a little extra space there.

  • The powdered buttermilk that I buy at the grocery store required refrigeration after opening. I have read the post here and from it I gather that once I open PP's powdered buttermilk that I can use it in pantry mixes, leave it in the pantry vs. the fridge, etc? I want to be certain before I buy any. Thanks.

  • how about putting a vacume seal on it in a jar or plastic bag? that should deprive it of O2? Also would it be better to simply buy canned dog food or vacume seal dry kibbles in canning jars? I wonder if the fat content would hold up under a vacume or rancidify. Not only is fido part of the family, he might earn his kibbles by alerting us of ner-do-wells in certain stituations

  • Had some freeze dried packaged foods in the garage overhead. Pulled it down and found the packages were wet on the outside. All were unopened. Do you think there still good after being in such heat ?

    • Storing food in hot temperatures can drain the shelf life drastically, depending on how hot it gets. Really, the only way to tell would be to open it. If the moisture somehow got into the can, then it probably won’t be good to eat. Likewise, it also depends on how long the cans were sitting in the heat. The longer they were exposed, the less likely they are to be good.

  • We are looking to move to an older home that has had a lot of moisture in the basement, we hope to remedy that. But will cans store OK in the basement if not opened? Would I just need to watch for signs of rust?

    • They will still be fine, but the shelf life will deteriorate the more humid the location. Rust is an issue, but sometimes you might not be able to see the tiny holes rust creates. A dehumidifier would be a good thing to use in that room.

  • I ha e a bag that has been opened thatbid freeze dried. Has a best buy 12/15 sticker. How long is it good for? We ha e heard that best buy dates are not always what you should go by.

    • Hi Kimberly,

      Usually, if a freeze-dried food is unopened, it can last anywhere from a few days to a month or more. It really depends on the heat and humidity in where it’s being stored. So while I can’t necessarily give you an exact time frame, you can judge for yourself according to how it looks, smells and feels. If it’s getting squishy, that means it is retaining moisture, and moisture is one of the things that makes food go bad. However, if you just opened the bag that had a best buy date of 12/15, then give it a look, and if it’s retaining moisture, it might be best to get rid of it. However, we have done tests which show many freeze-dried products, MREs, and other long-term food supplies, will be very much edible many years after their best buy or expiration date.

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