The seal is one of the key processes for long-term preservation of canned food
Seal is the sterilization of canned foods in isolated, no longer subject to outside air and microbiological contamination caused by corruption. When canning containers the loss (or instantaneous time) it should be sealed, it cannot achieve long-term food preservation purposes. Metal can sealing done by can-sealing machine, sealing machine the most common semi-automatic, automatic and vacuum sealing machine (Food Engineering). Container seals rely on brim shape or form lid to different volume letter, rotating, or cover type capping machine for sealing. Plastic composites (bag or Cup) of commonly used high frequency sealing, hot and pulsed sealing method for edge, cover.