Many food companies need vacuum packaging of hot food according to their own product conditions. Such vacuum packaging machine also needs special structure to heat-seal products.

Generally, it is required to be cooled to room temperature before packaging. According to the theory, the vacuum of hot vacuum will be relatively high, the total number of bacteria in hot packaging is easy to control (sterilization is complete, there is no advantage) but depending on the type of products, such as making zongzi, all require cold packaging, mainly cold packaging can reduce the moisture content of zongzi. Other products should also be selected according to the characteristics of the products. Generally, most products are packed at room temperature, because the hot packaging process is difficult to operate. Basically, it is still measured by hand. After high temperature vacuum packaging, the vacuum degree is not as high as that at room temperature, so it is easy to leak.

Then will product heat seal affect the vacuum pump of conventional packaging machine? Naturally, because hot vacuum pumping will drain a large amount of water vapor, if the vacuum pumping equipment is oil seal, then a large amount of water enters the vacuum pump and mixes with the vacuum pump oil, one is easy to overflow, the other is easy to scrap the vacuum pump oil.

The principle of vacuum packaging for food at room temperature is that the main cause of food mildew and deterioration is the activity of microorganisms, and the survival of most microorganisms (such as molds and yeasts) needs oxygen, and vacuum packaging is to use this principle to extract oxygen from the packaging bag and food cells, so that microorganisms lose their "living environment". Experiments show that when the oxygen concentration in the packaging bag is less than 1%, the growth and reproduction speed of microorganisms will decrease sharply. When the oxygen concentration is less than 0.5%, most microorganisms will be inhibited and stop breeding. (Note: Vacuum packaging can not inhibit the food deterioration and discoloration caused by anaerobic bacteria reproduction and enzymatic reaction, so it needs to be combined with other auxiliary methods, such as refrigeration, quick freezing, dehydration, high temperature sterilization, irradiation sterilization, microwave sterilization, salt pickling, etc.).

Therefore, customers should choose and purchase vacuum packaging machine according to their own product requirements.