Know about food heating bags | Updated: 2022-04-20
1.There are many kinds of heating bags and the heating process is simple.
Self-heating technology for food was initially developed for military needs. With the progress of technology, heating packages have entered the market, and more types have become available, using magnesium-iron powder, quicklime-iron and quicklime-aluminum.
Two or more chemical substances react to release heat, so as to prolong the heat release time and reduce the cost of raw materials. The heat release process basically does not produce harmful gases, and there is no need to worry about pollution.
Most heating packages for food are of the quicklime-aluminum type. When put into water, the chemical substances react to release heat, so that the water will reach the boiling point in a short time and produce steam. Food can then be put on the upper layer and heated.
2.The harm of the heating bag varies at different stages 
1) The heating bag before use is the most harmful
Firstly, eating the raw materials of the heating bag by mistake can burn the mucosa of the oral cavity and the digestive tract, because the raw materials can react with water and gastric acid in the oral cavity and the stomach, resulting in gastrointestinal irritation and burns, and mucosal erosion. In serious cases there are symptoms such as water and electrolyte disorder.
Secondly, inhaling a large volume of powdery particles in the heating bag can also irritate and burn the respiratory mucosa, and result in respiratory irritation symptoms, throat dryness, or hoarseness.
Finally, if you touch the heated powder when your hand is wet, your skin will be burnt.
Therefore, don’t tear the package of the heating bag.
2)The heating bag in the heating process is also harmful
Don’t touch the heating bag during the heating process. The temperature of the heating bag can reach more than 150 ℃, and the temperature of the steam can reach 200 ℃. 
If there is a clear white foam and lime water flowing into the food, it is better to discard the food, as there may be a large number of alkaline substances that have not completed the reaction, which will irritate or burn the digestive tract. 
3)The heating bag after use does not cause much harm
The used heating bag is as hard as white mud and is harmless. However, the remaining water after heating is alkaline. The acid-base test strip should display between 10 and 11; the value of pH is 10.75. This water also contains a variety of salts and oxides, which may have potential health hazards if ingested, but it will not cause acute organ damage.
Left: The heating bag turns into stone-like material after use.
Middle: Use the PH strip to test the heated residual water.
Right: PH value of heated residual water is 10.75 [Photo/]
3.Use the heating bag correctly
Precautions of the heating bag and how to use it are indicated on the package of self-heating food. As long as you handle it correctly, there will be no danger. Don't add hot water! Don't block the vent at the top of the lunch box.
The heating bag is not food and cannot be eaten. Take care of your children and don’t let them tear or eat the raw materials of the heating bag by mistake.
If you accidentally eat the raw materials of the heating bag, you can eat egg whites or drink milk and should see a doctor as soon as possible.