Behind every great sandwich is a fresh loaf of bread. Though you can search a bread bag for the expiration-date fine print, there's another small detail that will quickly and easily tell you how fresh its contents are: the twist tie.

That's right, the plastic tags or metal ties that are piling up next to your paper clip collection tell you which day of the week bread was baked on. The codes are as follows: Monday – blue, Tuesday – green, Thursday – red, Friday – white and Saturday – yellow. (We didn't forget about Wednesday and Sunday: Most sources refer to a five-day delivery schedule.)

The reason behind the color coding is to make it easier for employees to remove stale loaves from the shelves and replace them with fresh ones. Need an easy way to remember the schedule? The colors go in alphabetical order, making it one less thing to forget as you cruise the aisles.

Keep in mind that some companies might have their own system, so check the expiration date when in doubt.

Check out our best sandwich recipes.