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is this really true? radioactive mres!
Posted: Wed May 07, 2008 5:22 am
by German_EPA
Re: is this really true? radioactive mres!
Posted: Wed May 07, 2008 6:14 am
by mreheater72
I have heard these statement many times before, too. But whether it is true, I really don“t know.
So long mreheater72
Posted: Wed May 07, 2008 10:01 am
by Big Galloot
The thing to remember is that irradiated foods are generally irradiated AFTER they have been packed and sealed to eliminate any possibility of contamination.
The trilaminate retort pouches used for an MRE entree includes an aluminum foil lamination which presents a barrier to that radiation. This is why microwaving an MRE is a bad thing.
Because the aluminum foil layer represents a substantial barrier to irradiation, I tend to believe that if they were using irradiation that they would use an all polymer retort pouch.
The good news is that we can replace our dumb looking tin foil hats with stylish MRE pouch hats!
Posted: Wed May 07, 2008 10:25 am
by kman
I think irradiation is a fairly common practice in the food packaging industry. But like Big Galloot says, most foods are irradiated after they're packaged so I'm not sure how this would work for an MRE pouch.
I did some quick googling and found one page at Natick that talks about irradiation for food processing:
http://www.natick.army.mil/about/pao/2006/06-15.htm
Technology transfer highlights through the years at the Natick Soldier Center
[..]
Food Processing and Packaging Technologies:
Food irradiation. During irradiation, foods are exposed to electron beams or cobalt gamma rays. The process kills bacteria by briefly altering the electric charge of the molecules in the food and microorganisms. Food irradiation increases food safety and shelf life. Irradiated foods are more nutritious and better tasting than foods processed with other methods. Food irradiation is used in the commercial sector as a means of preserving food. NSRDEC has a long history of producing irradiated foods for the space program and pioneered irradiation in the 1960s.
But I couldn't find anything that spoke specifically about MREs being irradiated. Just some mention about how Natick used irradiation to prepare foods for the Apollo space missions and how this led to the development of MRE bread.
Posted: Wed May 07, 2008 1:59 pm
by German_EPA
thats really a strange thing...

Re: is this really true? radioactive mres!
Posted: Wed May 07, 2008 7:20 pm
by MCIera
I thought irradiation was used to prolong the shelf life of perishable fresh foods (e.g. fruits and vegetables.) Shelf stable foods would not need this since they're cooked in their packaging and the packaging itself, whether it be a can or retort bag, would be maintaining it's usability.
Posted: Thu May 08, 2008 12:08 am
by RoastBeastFan
I would think MCIera is correct - the heat sterilizes an MRE. No point making it deader, unless you've got zombie bacteria or something. The irradiated foods I've heard of have been fruits (things like strawberries, which are prone to spoil fast).
I don't think that tiny aluminum layer of an MRE pouch is going to slow down a Cobalt gamma ray very much. The Co-60 gamma rays have energies over 1 MeV, and have excellent penetration, aluminum foil won't do the trick. Think more like 3 or 4 feet of concrete.
I believe irradiated food is a huge controversy over in Europe. German_EPA, it isn't often discussed over here. I don't think we have much irradiated food here -- but it's probably because of the expense, not because of radiation fears.
Posted: Thu May 08, 2008 8:49 am
by Big Galloot
I agree that a thin layer of aluminum will not "stop" radiation, but it does produce an energetic result that makes it a poor choice to include in packaging for that purpose. Try placing an MRE entree in your microwave and you will see my point.
The value of irradiating shelf-stable foods is that it kills bacteria without cooking the food. You might notice that how all MRE meats have been overcooked to death, this is required by the process. Irradiation can produce a shelf-stable rare burger as well as the uncooked but bacteria free strawberries you noted.
Posted: Thu May 08, 2008 9:28 am
by housil
I read an article about, that explains how that work.
They use just "ionized irradiation".
Most people are concerned that this may cause radioactivity in/on/at the food.
They definly deny that!!
There is UV-C irradiation in use to destroy the DNA of the bacteria, mold etc. to prevent multiplication of food-spoiling-microorganism. So the food is just "clean", but
not contaminated
Fresenius. Germany
http://www.fmcna.com/
retort process
Posted: Fri May 09, 2008 7:42 am
by barzongak
all the mres and cans will be sterilized after filling and sealing in large
autoclaves ,the process called retort.
there is no radiation specially today that high frequency magnetic fieldes
have had very good results in sterilizing food products.