If you buy apples, you are undoubtedly familiar with the little plastic sticker that mars the otherwise shiny, red exterior of your afternoon snack.  What you don’t know is that the sticker is trying to tell you something very important.

According to the Consumer Reports Health blog, those price look-up (PLU) stickers contain a coded message about the origin of your produce.  For instance:

• A five-digit number that starts with a 9 means the item is organic.

• A four-digit code beginning with a 3 or a 4 means the produce is probably conventionally grown. For example, regular small lemons sold in the U.S. are labeled 4033, large are 4053; small organic lemons are coded 94033, large are 94053.

• A five-digit code that starts with an 8 means the item is genetically modified (it has genes from other organisms). You won’t see many of those because only genetically modified versions of corn, soybeans, canola, cotton, papaya, and squash are now widely sold. And because PLU codes aren’t mandatory, companies can label those items as conventional.

With a pesticide rich crop like apples, that little “9″ could make a very big difference.  For a handy reminder of which crops are higher in pesticides, check out the “Dirty Dozen Cheat Sheet” from Heidi Kenney.

Print it out and stick it in your wallet for an easy way to remember which foods you should buy organic, and which foods you can safely eat the cheaper, conventionally grown varieties.  Make a note on the card to look for the number 9!

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1. 7 Foods the Experts Won’t Eat
2. Why does organic food cost more?