Why is there generally no expiration date for chewing gums?

Chewing gum is a very stable product because of its non-reactive nature and its low moisture content. Because of this, chewing gum retains its quality for a longer time than most other food products – so long, in fact, that chewing gum is not required by law to be labeled with an expiration date in most countries. Chewing gum that is not used may, over time, become brittle and lose some of its good taste, but the product will remain safe to chew.