Originally designed for the U.S. government, MREs—or Meals Ready to Eat—are compact pouches that contain delicious, ready-to-eat foods. The U.S. Space Program, Military, Forest Service, and FEMA have used MREs since the 1970s. In more recent years, many foreign governments have started using them, as well.
Shelf life has always been an important factor in the development and testing of rations for the U.S. government. All MRE foods are packaged in triple-layer plastic/aluminum pouches that have better storage qualities for military use than heavy cans. The food in these pouches is precooked and sealed at a high temperature; bacteria are neutralized and the food is shelf-stable even when stored at room temperature. Some of the best information available on MRE shelf life is the storage life chart (see below) compiled by the U.S. Army's Natick Research Laboratories. This chart provides a good overview and summary of the findings gathered from their testing of MRE products:
More about MRE Shelf Life
The shelf life ratings shown in the chart above were determined by taste panels of "average" people— mostly office personnel—at the Natick lab. Their opinions were combined to determine when the MRE ration was no longer acceptable.
The shelf life determinations were made solely on the basis of taste, as acceptable nutritional content and basic product safety extend far beyond the point where taste degradation would occur. This means that MREs would be safe and give a high degree of food value long after the timing suggested in the chart, as you can see by watching the short video below. We had some 30-year-old MREs tested at a food lab to make sure old MREs are safe to eat while still maintaining their nutrients. The results were quite enlightening:
MRE pouches have been tested and designed 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 at 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.
Freezing an MRE pouch does not destroy the food inside, but repeated freezing increases the chance that the stretching and stressing of the pouch will cause a break on a layer 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.
Note: Time and temperature have a cumulative effect. For example, storage at 100° for 11 months then moved to storage at 70° would lose one-half of the 70° storage life. Also avoid fluctuating temperatures, in and out of freezing levels. Due to the cumulative effect of time and temperature, a regular rotation of MRE's within 5 to 7 years is recommended.