In canned plants, physical controls are carried out at certain stages of production at frequent intervals and after each sterilization by taking samples from canned foods. During these checks, the overall appearance of the can, gross weight, tare and net weight of the can, filtration weight, filling rate and head space as well as the amount of vacuum are determined.

In hermetically sealed canned cans, the difference between the internal pressure in the head space and the external atmospheric pressure is determined by vacuum measurement. In simple terms, vacuum means the lack of air in the can, ie oxygen. In cans or glass canisters, vacuum is created if the internal pressure of the can is lower than the air pressure. As the difference between the internal pressure in the can and the external atmospheric pressure increases, so does the vacuum value.

Vacuum has many physical, chemical and biological effects. For example, vacuum prevents the growth and proliferation of aerobic microorganisms in the can. It proves that the foodstuff is sterilized by the appropriate method. The vacuum also prevents the clamps from being forced by high internal pressure during sterilization. Also, oxidative deterioration and rancidity in foodstuffs are prevented by vacuum. Prevents discoloration and vitamin loss in canned products. An effect of the vacuum is to prevent the accumulation of corrosion-induced hiderogen gas in the headspace and the bombing of corrosive foodstuffs in the can. In addition, tight holding of the lid of the jar is thanks to the vacuum.

The amount of vacuum in canned food varies depending on the filling temperature of the food, its expansion property, the amount of head space, the heat treatment temperature and the dimensions of the can.

Within the scope of package analysis in advanced laboratories, studies are carried out to determine the amount of vacuum in cans and glass canisters. During these studies, standards and test methods published by national and international organizations are based.