When you buy a bag of chips or whatever it will stay fresh for a long time but once you open the bag it will only last for a few days. How is this possible?

Question

Like there is air in the bag as well so how come it can last for longer period of time when sealed?

In: Earth Science

Answer 1

*”…there is air in the bag…”*

Your premise is wrong. There’s no “air” ^oxygen in the bag until you open it. Bags are factory purged/filled with Nitrogen specifically to keep the contents from oxidizing in transit & storage. They’re also filled out fully to protect the contents from damage in shipping. Once you open it you’ve now exposed the contents to both oxygen and moisture, both of which have a negative effect on the freshness of the chips inside.