We rely on best-before dates to make sure that what we're buying is safe to eat, and that food is as fresh as it looks.

CBC Marketplace spoke with grocery store insiders who confessed to common industry practices used to sell you food that is past its prime.

Marketplace tested to find out whether food treated this way is safe to eat.

For more grocery store tricks, and how to make sure you're buying food that's fresh, watch the Marketplace investigation Friday at 8 p.m. (8:30 p.m. in Newfoundland) on CBC TV and online.