The term hermetic refers to a container that is sealed completely against the ingress of gases and vapors. The package can be considered as an air or liquid tight container.
Such a container, as long as it remains intact, will also impervious to bacteria, yeasts, molds and dirt from dust and other sources.
The most common hermetic containers are rigid metal cans and glass bottles, although faulty closures can make them non-hermetic. Canned food can be defend as thermally processed shelf-stable foods in hermetically sealed containers, regardless of the type of container (metal, plastic, paper, etc) or how the thermal process was delivered.
The quality of the seal can readily be ascertained by coating the ampoule with a leak-detection compound or detergent solution, then pacing it in a bell jar of vacuum desiccators and evacuating. Any leaks present will result in an easily seen stream of bubbles.
Hermetically sealed container