What is the cause of the vacuum packing bag bilge gas?

In order to extend the shelf life of products, we are often in areas such as food, daily chemical products using vacuum technology. Is the purpose of the vacuum pump all the bags in the air, prevent bacteria inside the bag, which can lead to product metamorphic corruption. But placed after a period of time, some vacuum bags happen bilge gas is what causes? Air tightness and vacuum packaging itself problem 1. There are three factors, which affect the air tightness: strength, composite viscosity and sealing. Strength: because of air pressure, vacuum packaging bags after vacuum packaging folds will happen, if there is a sharp, water chestnut products, packaging, such as rice, chicken bones do thinner bags can easily stabbed broke, in the process of transportation bag friction between the torn bags also causes the invasion of the bacteria. Composite viscosity: vacuum bags are generally used to compare the soft PA + PE compound and into, if the bonding strength between the PA and PE is not enough, there's nothing wrong with time of pumping air into vacuum state, but a long time, will happen bulge bag of leak phenomenon. Seal: vacuum bags at the time of the factory will set aside a cut products, sealing time if there is no real seal, sealing would also bulge bag. 2, 1 type anaerobic microbial breeding. Exclude air tightness problem, we will swell the gases in the bag, take out, then inject lime water clarity, gently if limewater turbid, the gas is carbon dioxide, carbon dioxide is produced a large number of microbial breeding. Then consider the sterilization ways if you have any questions. ( Ps: some students may be confused, the packing bag of nitrogen filling is also extend the shelf life, the same & other Bulge bag & throughout; , but why to eat, and vacuum bags & other; Bilge gas & throughout; Is not? )