Tuesday, September 20, 2011

Continuity Insurance - Food Storage - MREs (Meals-Ready to-Eat)

Today's lunch special is MREs. Just a little info and history. 


Meals Ready to Eat (MRE's)

These were originally designed for the U.S. government. The compact pouches contain delicious ready to eat foods. MRE's have been used since the 1970's in the U.S. Space Program, Military, Forest Service and FEMA. More recently, many other governments have started using these foods. Today we have civilian versions of these foods and the military version is actually illegal to sell to the general public.

One of the biggest concerns in the development and testing of rations for the U.S. government has always been shelf life. All MRE foods are packaged in triple-layer plastic/aluminum pouches that have better storage qualities than heavy cans, so there’s no need for a can opener. The food is precooked and the pouches are sealed at a high temperature so that any bacteria are killed off and the food will be shelf stable even when stored at room temperature. Some of the best information available on MRE shelf life is the storage life chart (below) compiled by the U.S. Army's Natick Research Laboratories. This chart provides a very good summary of their findings.


Storage
Temperature(°F)
Months
of Storage
120°
1
110°
5
100°
22
90°
55
80°
76
70°
100
60°
130

Note: Time and temperature have a cumulative effect. Meaning that if you store an item at 100°F for 11 months then move it to storage at 70°F, it would lose one-half of the 70°F storage life (adding 50 instead of 100 months to the storage life). Avoid varying temperatures, in and out of freezing levels. Because of this cumulative effect, MRE's should be rotated and used within 5 years.

The shelf life ratings shown in the chart above were determined by ‘taste panels’ (groups of average people, mostly office personnel) at the Natick lab. Their opinions were combined to determine when a particular component, or in this case the entire MRE ration, was no longer usable.

The shelf life determinations were made purely on the taste, because of the fact that the important nutritional content and basic safety would last long beyond the point where taste became ‘yucky’. This means that the MREs would be safe and still have a high degree of food value for quite some time after the lengths of time listed in the chart.

MRE pouches have been redesigned where needed according to standards much stricter than for commercial food. They must be able to stand up to abuse tests such as obstacle course traversal in field clothing pockets; storage outdoors anywhere in the world; shipping under extremely rough circumstances (such as by truck over rocky terrain); 100% survival of parachute drops; 75% survival from free failure drops; severe repetitive vibration (1 hour a t G vibration); 7,920 individual pouch drops from 20 inches; and individual pouches being subject to a static load of 200 pounds for three minutes.

The freezing an MRE pouch does not destroy the food inside, but freezing it over and over again will increase the chance that the stretching and stressing of the pouch will cause a break any one of the seals of the laminated pouch. These pouches are made to withstand 1,000 flexes, but repetitive freezing does increase the failure rate by a small fraction of a percent. Also if MRE food is frozen, then thawed out, it must be used the same as if you had thawed commercial food from your own freezer at home.

Copyright ©2010 Noel Napolitan


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