I read this earlier today and found it kinda cool:

Bread is delivered fresh to stores 5 times a week, Monday, Tuesday, Thursday, Friday and Saturday and each day represents a different colour.

Monday - Blue
Tuesday - Green
Thursday - Red
Friday - White
Saturday - Yellow

The twisty ties and/or the plastic ties all follow that color scheme, so if you go to the store on a Monday, buy bread that has a Blue tie on it, or on a Tuesday, a green tag on it, etc.

I just wonder if nobody bought the bread the past week, do they get rid of it or replace it with fresh bread?