page_title: Canning
section_title: Seaming
hierarchical_section_title: Canning / Methods / Double seams / Seaming
caption_attribution_description: 馬口鐵罐頭食品zh:涼粉
context_page_description: Canning is a method of preserving food in which the food contents are processed and sealed in an airtight container. Canning provides a shelf life typically ranging from one to five years, although under specific circumstances it can be much longer. A freeze-dried canned product, such as canned dried lentils, could last as long as 30 years in an edible state. In 1974, samples of canned food from the wreck of the Bertrand, a steamboat that sank in the Missouri River in 1865, were tested by the National Food Processors Association. Although appearance, smell and vitamin content had deteriorated, there was no trace of microbial growth and the 109-year-old food was determined to be still safe to eat.
context_section_description: The body and end are brought together in a seamer and held in place by the base plate and chuck, respectively.  The base plate provides a sure footing for the can body during the seaming operation and the chuck fits snugly into the end (lid).  The result is the countersink of the end sits inside the top of the can body just below the flange.  The end curl protrudes slightly beyond the flange.
caption: Opened can
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