The History of Ready-to-eat Rations

The earliest ready-to-eat rations were provisions that soldiers carried with them to eat in battle. Ready-to-eat rations first appeared in Napoleonic times, and at first they were tinned, simple in variety and mediocre in taste.
Ready-to-eat rations have changed a lot with the development of time and technology.
The first variety is various, such as high energy biscuits, canned food, MRE, etc.The military series MRE, for example, has the mushroom with minced meat, white noodles, fried rice, sauce beef, energy bar, instant powder drinks, chewing gum, chocolate, sweet crisp cucumber, spicy cabbage, dried blueberry or mango.  High energy, nutritious ingredients, rich taste.
The second packaging method is also constantly updated.  From the previous canning method to the present pressure flexible packaging bags. Canning is an extremely common food preservation technique that has been widely used for more than 100 years.  The basic principles of canning are very simple.  Cook the food in the jar to kill all bacteria in the jar, then seal the jar (either before or after cooking the food) to prevent new bacteria from entering. Today's laminated flexible packaging bags are soft in texture, made of thick aluminum foil and multiple layers of plastic.The packaging has three advantages over cylindrical metal cans: it's lighter and more flexible, meaning it can withstand more damage in the wild, and it's flat and can be carried easily in a backpack or pocket.  The flat shape also gives the package an advantage in handling.  At the factory, food needs to be packed into bags, then sealed and boiled for disinfection.The time it takes to heat food to the temperature needed to kill bacteria is greatly reduced.  This usually makes the product taste better.

The third heating method changes. All military MRE are now packaged with a flameless heater.  Flameless heaters use a simple chemical reaction to provide enough heat to heat food.  The principle of flameless heaters is to use the oxidation of metals to generate heat.