As the discussion over food waste has grown in recent years, the expiration dates put on products have increasingly come into the crosshairs. What do things like “sell by,” “use by” or “best if used by” really mean? Who comes up with these dates and how? Will I die if I eat old bagged lettuce or will I just end up with a gross but edible salad?
The site The Conversation specifically set out to explain all the different ways these dates are decided on. Of course, no one set method exists, which is part of the problem. Instead, brands will pick from a number of different processes. Some are highly scientific: “Microbial challenge studies” will actually add a pathogenic microorganism to a food, and then researchers will try to mimic the conditions that product will withstand all the way to a customer’s home, testing the product along the way. “Mathematical modeling tools” are also scientifically-based, using the results of previous challenge studies to extrapolate out a products shelf life.