I didn't know until I read it that the little stickers on loose fruits and vegetables have valuable information on them! According to a letter from 'a scientist knowledgeable in the field of genetically modified organisms (GMOs)' in the October 2003 issue of Gourmet magazine:

"A useful tip to the consumer [would be] a primer on how to read the little stickers on loose fruits and vegetables. Besides providing the store's cash registers and computers with product identification and price information, these stickers can tell you a lot about the food you are buying.

• A label with four digits indicates conventionally grown food. [i.e. -subjected to an unknown amount of herbicides, pesticides and other agri-chemicals]
• Labels with five digits starting with an 8 indicate that the food is genetically modified.
• Labels with 5 digits starting with a 9 indicate that the food is organically grown."