With the continuous improvement of living standards, people pay more and more attention to food safety, and the application of vacuum seal bags has become increasingly extensive. Vacuum seal bags are also known as decompression packaging. All the air in the packaging will be pulled out, maintaining the bags in a state of high decompression which is equivalent to the effect of hypoxia. In this circumstance, microbes have no living conditions so that it achieves the purpose of keeping food fresh and stopping spoilage. And the performance of vacuum packaging materials directly influences the storage time and the taste of food. So, can vacuum bags be heated?
Not all vacuum bags can be heated directly, which is generally related to the materials and the workmanship of vacuum seal bags. The common bags only own the function of vacuum pumping, and some plastics will release harmful chemicals in high temperatures or acidic conditions. Fortunately, the vacuum bags for sous vide cooking sold on the market are composite bags made of PE+PA that is polyethylene and nylon. These materials don't contain plasticizers such as phthalate and don't release bisphenol-A. And the food-grade silicone bags, which are up to the standard of food sanitation, can be reheated. Hence, when purchasing vacuum bags, we need to choose those with detailed introductions of materials and brand guarantees. And read the instructions on the bags carefully before using.
In addition, many people seem to have a misunderstanding about vacuum seal bags for high-temperature cooking. It is wrong for them to believe that all these bags can be microwaved likewise. Because the temperature in the microwave oven is much higher than that of boiled water. In the process of heating in the microwave, the moisture of the food will be vaporized and separated by the vacuum bags, and the heat energy will not be released to the outside, which leads to the rapid expansion of the volume and the explosion of bags. Therefore, it is necessary for us to read the introduction on the packaging first. If they are not suitable or allowed, open the vacuum bags before we microwave the food or prepare a canister that can be heated in the microwave oven, which is safe and convenient and can be recycled.