MRE, which stands for “Meal, Ready-To-Eat”, are meals that come in plastic pouches known as retort packaging. But how MREs are made? This package is made up of plastic and aluminum foil that has been layered together.
These MRE pouches contain standard food such as beef or chili stew. This food is first pre-cooked and then placed inside the pouch before it is sealed. The food inside the pouch and the pouch is then heated for the purpose of sterilization.
Due to the seal, the food has the ability to last for longer periods of time. This is similar to the process of glass or metal canning, where food stored in a can undergoes sterilization through heat in containers that are sealed to stop bacteria and oxygen from getting in and spoiling the food. Retort packaging can be compared to flexible cans. The meals inside these pouches taste the same as canned beef or chili stew.
This same retort packing is used for various drinks using the same technology utilized to make the MREs.
How Do The MREs Work?
The majority of people prefer a warmed meal in comparison to cold ones. This is especially true in wet and cold conditions. Eating a cold stew or spaghetti is generally unappetizing. While hot meals are the ideal choice to lift one’s spirits such as soldiers out in the field. Due to the importance associated with a warm and hearty meal, all of the MREs are packaged with the flameless heater. These flameless heaters make use of a basic chemical reaction that offers enough warmth to heat up the food.
This form of chemical heating is a natural and widespread phenomenon. For example, the process of iron rusting is a common occurrence. Rust is described as a process that is natural that involves the atoms in the iron that combine with the oxygen atoms. This results in a crumbly and reddish iron oxide. These processes usually occur slowly, but when iron is exposed to water it rusts a lot faster and iron that is exposed to ocean water is known to rust the fastest.
When iron converts into rust, this oxidation process is what generates heat. However, the rust develops slowly and the heat that is generated is barely noticeable. The oxidation reactions that are faster include oxidizing carbon atoms inside charcoal briquettes, where they generate a significant amount of heat. The word “burning” is used for describing these high-speed forms of oxidation.
The flameless heaters use similar principles in the process of oxidizing a metal in order to generate and produce heat. The magnesium metal performs more efficiently when compared to iron, due to its ability to rust a lot faster. The flameless heater is made up of a magnesium dust combined with salt as well as a small amount of iron dust into a flexible and thin pad that is compact and easy to carry.
The activation of this heater involves adding a small amount of water to the pad. Within a few seconds the heater reaches boiling point and starts to steam and bubble. When it comes to heating the MRE, all that is required is the insert the MRE pouch and the heater back into the provided box which the pouch came out of. Within 10 minutes the meal is ready for consumption.
Facts About MREs
• The MRE (Meal, Ready-To-Eat) were first introduced and served to the soldiers in the year 1980. The MRE went onto replace the Meal, Individual more commonly known as the C-Rations, which were in use since the time of the Vietnam War.
• These meals have a shelf life of around 3 years when stored at 26 degrees Celsius and around 6 months if stored at a temperature of 38 degrees Celsius.
• The packaging of the MREs are made to withstand harsh transportation requirements associated with the military.
• The secret to the MRE shelf-life is due to the tri-laminated foil packaging that protects the food from moisture and oxygen. Moisture and oxygen are the 2 main factors that contribute to food spoilage.
• The vacuum seals on these pouches keep out oxygen and moisture, while oxygen scavengers absorb any excess oxygen which contributes to preserving the freshness of these meals and extending the shelf-life.
• The thermal process that involves canning inside a pouch is what protects the fruits and the entrees of the MREs. The cooked meals are then exposed to high pressure and heat that kills the presence of any microorganisms that are responsible for spoiling and mould.
• The MREs have been designed with the purpose of meeting up to the RDA (recommended daily allowance) for Military guidelines which were first established by a surgeon general. With the focus on a highly active and healthy population, the military RDA features higher protein and calorie requirements.
• Flameless ration heaters have allowed a way for soldiers to heat up their food while out in the field. With the addition of water, the reaction with magnesium iron compounds makes the water boil. This heating process has the advantage of not producing any chemical by-products.