# Spoilage of freeze-dried food **URL:** \ **Category:** Factual Questions\ **Created:** [May 15, 2005, 6:17am UTC](https://boards.straightdope.com/t/spoilage-of-freeze-dried-food/303916 "2005-05-15T06:17:05Z")\ **Posts on this page:** 9\ **Page:** 1
**Author:** ![Mathochist](https://avatars.discourse-cdn.com/v4/letter/m/c89c15/32.png) [@Mathochist](https://boards.straightdope.com/u/Mathochist)\ **Post date:** [May 15, 2005, 6:17am UTC](https://boards.straightdope.com/t/spoilage-of-freeze-dried-food/303916/1 "2005-05-15T06:17:05Z")
Chuck Palahniuk’s most recent book involves as a major plot point some form of freeze-dried food. He doesn’t mention a brand (natch), so it’s probably easier to describe by just quoting the book > [@Haunted](#): > > For food, we had green beans sealed in Mylar bags you couldn’t tear with your bare hands. “Vermin-proof” was stenciled in black paint on each silver bag. We had vermin-proof green beans and chicken pot pie and golden-sweet whole-kernel corn. Inside each bag, something rattled, loose twigs and rocks and sand. Each bag inflated to a silver pillow with a puff of nitrogen to keep the contents dead. The lasagna with meat sauce or cheese ravioli. > To cook dinner, most people cut the bag open with scissors or a knife. You reached in and dug around until you found the little bag of iron oxide—added to absorb any trace of oxygen. You fished out the tea bag and dumped in so many cups of boiling water. You read ten pages in a vampire novel, and dinner was served. Instead of sticks and hot water, the silver pillow was full of home-style meatloaf or beef stroganoff. So, here’s my question (and hopefully this won’t give anything away): if you opened the bag of such food, how long would it take for the contents to spoil? I mean, sure it wouldn’t last as long as it was originally supposed to, but this sounds pretty similar to cup-o-noodles and that seems to last months without going bad. Would it depend how long the stuff had been in the bag so far? ---
**Author:** ![Shalmanese](https://avatars.discourse-cdn.com/v4/letter/s/45deac/32.png) [@Shalmanese](https://boards.straightdope.com/u/Shalmanese)\ **Post date:** [May 15, 2005, 8:10am UTC](https://boards.straightdope.com/t/spoilage-of-freeze-dried-food/303916/2 "2005-05-15T08:10:15Z")
It would depend a lot on the ambient mositure I’m assuming. Freeze dried foods are preserved because theyre dry. Once they soak up enough water from the air to start turning moist, then they’ll start to decompose. Then again, conventionally dried foods like jerky keep perfectly fine in the open. Perhaps the water affinity of the food would also be a factor. ---
**Author:** ![Broomstick](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/broomstick/32/246_2.png) [@Broomstick](https://boards.straightdope.com/u/Broomstick)\ **Post date:** [May 15, 2005, 11:14am UTC](https://boards.straightdope.com/t/spoilage-of-freeze-dried-food/303916/3 "2005-05-15T11:14:25Z")
Yes, it all depends on how dry the food remains. If it gets thoroughly wet, it goes bad as quickly as any other soup, stew, or similar food. If it gets damp, it gets moldly. Or full of mildew. But if opened and kept dry it should remain OK for several days, maybe a week. Dry and cold will last longer than hot and humid. There there is the vermin problem - once it’s opened you have to worry about rats, mice, bugs, raccoons… ---
**Author:** ![Mathochist](https://avatars.discourse-cdn.com/v4/letter/m/c89c15/32.png) [@Mathochist](https://boards.straightdope.com/u/Mathochist)\ **Post date:** [May 15, 2005, 12:31pm UTC](https://boards.straightdope.com/t/spoilage-of-freeze-dried-food/303916/4 "2005-05-15T12:31:36Z")
> [@Broomstick](#): > > But if opened and kept dry it should remain OK for several days, maybe a week. Dry and cold will last longer than hot and humid. Huh. I’m surprised that cup-o-noodles cups are well enough sealed that they push the time from a week to months. At least, I’ve eaten some I’m sure were kicking around in the pantry for that long with no ill effects. ---
**Author:** ![Broomstick](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/broomstick/32/246_2.png) [@Broomstick](https://boards.straightdope.com/u/Broomstick)\ **Post date:** [May 15, 2005, 12:56pm UTC](https://boards.straightdope.com/t/spoilage-of-freeze-dried-food/303916/5 "2005-05-15T12:56:46Z")
As long as the seal is sufficient to keep moisture and vermin out, it greatly extends the life of the food inside. I’m sure you could open a cup o’ noodles type package and, if kept in a truly dry and bug-free, rodent-free place it would continue to remain edible for long periods of time. Or if you poured it into a ziplock baggie and sealed that. The uncertainty comes in when you can’t be sure of moisture exposure or what may have been nibbling on it or lay eggs in it. ---
**Author:** ![Balthisar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/balthisar/32/2825_2.png) [@Balthisar](https://boards.straightdope.com/u/Balthisar)\ **Post date:** [May 15, 2005, 2:46pm UTC](https://boards.straightdope.com/t/spoilage-of-freeze-dried-food/303916/6 "2005-05-15T14:46:11Z")
When I was young, I learned a lesson in ambient humidity. Having grown up in Michigan (humid in the summer), it was always important to seal up the Doritos, 'tater chip, or Cheetos bag really, really well or they’d go stale really, really fast. They wouldn’t get soggy or anything, but just go stale. One time in Reno (dry, arid place) we’d left the car in valet parking at the Circus Circus for a week. We’d had a bag of Doritos in the car for the trip from Vegas. My dad was pleased to see the bag for the trip bag to Vegas. I remarked that they’d certainly be stale, but he gave me one and it was absolutely perfect, due to the lack of humidity. May seem perfectly obvious now, but I grew up, too, right? ---
**Author:** ![EvilGhandi](https://avatars.discourse-cdn.com/v4/letter/e/f17d59/32.png) [@EvilGhandi](https://boards.straightdope.com/u/EvilGhandi)\ **Post date:** [May 15, 2005, 11:10pm UTC](https://boards.straightdope.com/t/spoilage-of-freeze-dried-food/303916/7 "2005-05-15T23:10:41Z")
**Broomstick** "_There there is the vermin problem - once it’s opened you have to worry about rats, mice, bugs, raccoons…_ " Bwahaha, erm hahaha. ahem erm ok. I don’t know how much camping you’ve done, but I can assure you, rats and their brethern can smell food through a mylar bag. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [May 15, 2005, 11:25pm UTC](https://boards.straightdope.com/t/spoilage-of-freeze-dried-food/303916/8 "2005-05-15T23:25:20Z")
I don’t know about the cup kind, but I’ve had packets of Ramen that I’ve found small holes[sup]\*[/sup] in, that still tasted fine, after probably being in my cupboard for a month or two. Montana is pretty dry, though, so that may be a factor. And there are some freeze-dried foods that taste bad enough that I don’t think spoiling could make them any worse… I still occasionally have nightmares about freeze-dried enchiladas. \*not vermin-chewed type holes, just the seam coming apart a bit ---
**Author:** ![Broomstick](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/broomstick/32/246_2.png) [@Broomstick](https://boards.straightdope.com/u/Broomstick)\ **Post date:** [May 16, 2005, 7:52am UTC](https://boards.straightdope.com/t/spoilage-of-freeze-dried-food/303916/9 "2005-05-16T07:52:40Z")
> [@EvilGhandi](#): > > **Broomstick** > > "_There there is the vermin problem - once it’s opened you have to worry about rats, mice, bugs, raccoons…_ " > > Bwahaha, erm hahaha. ahem erm ok. > > I don’t know how much camping you’ve done, but I can assure you, rats and their brethern can smell food through a mylar bag. Yeah, but they can smell it better when there’s a hole in the bag. And a hole in the bag can frequently indicate critters have been at the food.