Step-by-step explanation:
Because of non-reactive properties of the inert gases, these gases are useful to prevent the undesirable chemical reactions to happen.
They provide a non-explosive environment. They are also cheap and economical.
Food is packed in the inert gas to prevent rancidity. This also prevents bacteria from growing.
The gases prevents the chemical oxidation by the oxygen in the normal air.
Helium is used in oxygen cylinders and also as a coolant in gas cooled reactors.