SurvivalistFilter part 3: Homemade MREs

October 23, 2007 1:05 PM

Survivalist/LazyStudentFilter: I need advise on the feasibility of making my own "canned" meals (but without the can), using boil-able/freezable/microwavable plastic pouches, a vacuum sealer, and a pressure cooker. May interest cheap and lazy students, busy people, and survivalists - if it works. Details inside...

So the theory goes: I cook the food and put it in a pouch (specs), vacuum seal the pouch, and pasteurize it in the pressure cooker. If this works, I would be able to make a big batch of food when I have time, split em up into smaller portions that are durable and don't require refrigeration, and be set on food for days. Cheaper, and certainly more nutritious than pre-prepared frozen foods. These food pouches would have the added bonus of doubling as MREs, for long term disaster preparedness.

The questions are:

1. Safety: How safe is this? I'm assuming the bags are hermetically sealed so air leakage = contamination, and conversely no air leakage = no contamination. But this assumption only works if the bags are sterilized. Assuming that I follow the homemade canned food guidelines for pressure cooker pasteurization (125 degrees celsius for X number of minutes), would proper sterilization have occurred? Or is home canning more of a "good enough, but not completely sterile" process?
2. Nutrition: How nutritious is the food, post processing? Will the pressure cooking significantly alter the nutritional content beyond that of normal cooking? Also, can I fortify the food with ground up multivitamin pills? Or would that significantly alter taste?
3. Shelf Life: Given a cool, dark environment, what's the shelf life of the plastic pouch, as well as the food? And would vacuum sealing all of it in a second mylar pouch (specs) significantly improve the shelf life?

Bonus questions: If I were to use the same process on dried fruits, would it significantly alter taste/nutrution? And would pressure cooking adversely affect the function of oxygen absorbers or desiccants that are packed with aforementioned dehydrated fruits?

posted by jytsai to food & drink (12 answers total)

Assuming that I follow the homemade canned food guidelines for pressure cooker pasteurization (125 degrees celsius for X number of minutes)

Generally the assumed guidelines with pressure cookers are maintained PSI over Time, rather than temperature. This is why they have pressure gauges and not thermometers built into the top of them. Also, you have used pasteurization and sterilization in an interchangeable fashion in your question - these are important distinctions.

The plastics will leech which is why the product page you linked has these fields outlined: WATERVAPOR TRANSMISSION RATE, O2 TRANSMISSION RATE. Depending on relative storage conditions would be problematic in this regard. Cans and mason jars don't breathe, this is why they are ideal for this application.

Will the pressure cooking significantly alter the nutritional content beyond that of normal cooking?

No.

And would pressure cooking adversely affect the function of oxygen absorbers or desiccants that are packed with aforementioned dehydrated fruits?

Desiccants generally are only capable of holding their weight in water, and pressure cookers are never used "dry". Plastics that leech water vapor would in turn pull in water vapor from all the pressure and steam. Although it is generally a negligible amount I have never dealt with this consideration in regards to foodstuffs intended for human consumption, let alone something prepackaged with desiccant.

I would be able to make a big batch of food when I have time, split em up into smaller portions that are durable and don't require refrigeration, and be set on food for days

If you mean to illustrate the idea of creating say - lasagna - and then pressure cooking it in various bags it should be noted that this will drastically affect the end product, as you can actually cook food directly inside of a pressure cooker in many different ways. I would say it is not a very feasible endeavor, and if it were someone would have made some money off it by now already!
posted by prostyle at 1:38 PM on October 23, 2007

I can only answer as someone who has canned foods and used a pressure cooker.

Canning is much simpler than using plastic pouches, and there is a lot of information about how to do it safely, and how long goods will last. Some things can be canned without additives, and some can't without stabilizers. There's no single answer. Foods with a higher acid content are much safer than those without.

As for pressure cookers and nutrition. Nutritionists will tell you that the raw food movement is crap, and it is, paricularly when you are talking about licopene, which is precious to those of us who have cancer free prostates. Each nutrient has its own storage issues. Some are destroyed by heat, others are created by cooking. Personally, I would rather have a vitimin pill alongside my food rather than in it.

Personally, I like pressure cookers for very few things. They cook the texture out of most everything. Fresh peas will be mush in seconds.

I don't mean to say this to discourage you. I love batch cooking (i have a freezer) and home canning. Any library/bookstore will have a wealth of information and recipies.
posted by gesamtkunstwerk at 1:42 PM on October 23, 2007

be vary wary of canning/preserving non-acidic acidic foods, botulism loves air free environments and requires a very high temperature to kill it (aka plastic may not hold up to that temperature). I would look into well researched books about canning and preserving to get the facts.
posted by estronaut at 1:57 PM on October 23, 2007

If you are selling this food, you are going to have to register with and be inspected by your local public health department. They will give you the rules about safety and shelf life.
posted by winston at 2:20 PM on October 23, 2007

You would have a big problem with the bags in your pressure cooker: as the pressure cooker cools down and loses its seal, it will suddenly drop pressure to atmospheric pressure, but the pressure inside your bags will still be about double that or only a little lower (because they will remain near 125C internally), and the bags will almost certainly pop.

There are some modern pressure cookers which don't have a sudden, explosive pressure drop as they cool, but I think the decline in pressure would be too steep for bags even with those unless you gradually turn the heat down, say over ~15 minutes.
posted by jamjam at 2:28 PM on October 23, 2007

The packaging of an MRE isn't just a plastic boilable bag - it's actualy a special laminate that essentually turns the pouch into a 'soft can'. I'm not sure that using a pressure cooker with a vacuum-sealer would be enough.

Dried fruit, meat and veggies however are no problem to vacuum seal.

Personally, I think your best bet is to simply package available commercial items into your own MRE. Some of those Hormel microwavable entrees (you can boil them as well) combined with a cracker and/or cookie snack pack and a fruit roll-up would make for a decent meal.

Add a condoment pack with a plastic spoon/fork, instant coffee, tea bag, sugar, salt & pepper, packet of instant soup mix, hot chocolate, handy-wipe, napkin, etc. Vacuum sealing will keep them together and safe from the enviroment. You can either take extra when you visit a fast food place or purchase them in bulk from a restaurant supply or foodservice place.

check out Ask Jackie and this Homemade MRE article for more ideas.

This will probably be heavier than a commercial or military MRE but easier to produce.
posted by Kioki-Silver at 2:43 PM on October 23, 2007

To package food for distribution you will need to be registered and inspected with your State food safety agency. Under current guidelines, the FDA requires food producing facilities to register with them and obtain a registration number, which I think is free. You can find more information here, also here (.doc) or by googling "food manufacture licensing".
posted by kuujjuarapik at 2:52 PM on October 23, 2007

To clarify: this won't be commercial. I put the "this may interest..." comment because the process/technique may be interesting to other people; not because I'm going to try to market to them. Sorry for the confusion.
posted by jytsai at 2:55 PM on October 23, 2007

Sorry, I thought you intended to market to lazy students and survivalists. For your own consumption, it is at your own risk.
posted by kuujjuarapik at 2:56 PM on October 23, 2007

Dried fruit won't require pasturization so you don't have to boil it.
posted by Kioki-Silver at 4:13 PM on October 23, 2007

If you were a pal of mine I'd try to talk you out of it, from the perspective of someone who cooks a lot, cans a fair bit, and probably has more experience with pressure cooking stuff in bags than anyone else here, if you can believe that (I used to work for this orchid nursery, see, and, well, it's a long story...)

A stock of unappetizing food with an indifferent shelf life as compared to stuff like, say, ramen and soup (and completely inadequate compared to professionally manufactured survival rations, which are freeze-dried and nitrogen packed, really the only way to go for multi-year storage) seems like an optimistic outcome to me. Pessimistic outcomes involve stuff like exploded food and melted plastic melded to the inside of your pressure cooker and botulism. If you already have the pressure cooker and the vacuum sealer, by all means feel free to experiment, but otherwise don't waste your money unless you are really likely to use these things in your day to day life (i.e. do you garden? Do you really like camping/hiking?)

Otherwise, treat the cheap/quick eating question and the survival rations question as two separate issues. There is tons of good advice online about the former, which will also involve stocking a rotating supply of food with reasonably good intermediate term storage profiles, like rice, dried beans, etc. If you are truly convinced it makes sense for you to deal with the latter, break down, google survival rations and spend a few hundred dollars on true professional rations; you can get them for 2-4 dollars per meal.
posted by nanojath at 11:23 PM on October 23, 2007

Several folks have mentioned botulism, and if you were still giving this serious consideration, it'd be worth paying extra attention to that. For short- or medium-term storage (cooking when you have time), I don't see the advantage over canning, which comes with a body of knowledge and good practices for inactivating botulinum spores and keeping your food safe. Really, how durable do these need to be?

More problematic is trying to make them into disaster preparedness supplies. Botulism in a disaster situation would be...disastrous, I guess. Although there's an antitoxin that can reduce mortality, treatment would still essentially be supportive care in a hospital.
posted by averyoldworld at 9:21 AM on October 24, 2007