Preservatives stop food from going rancid

The Montreal Gazette:(by Joe Schwarcz) Open a box of old crackers or potato chips and a smell emerges. It isn’t pleasant. The same goes for that bottle of oil sitting in the cupboard for months and months. It’s the smell of rancid fat, the result of “oxidation.” Simply put, some of the fat molecules have reacted with oxygen causing them to break down and release smaller malodorous molecules. Read more.