from: http://healthwyze.org/index.php/printer-friendly-plu-chart.html

The Meaning Of The PLU First Digit On Fresh Produce

8: The product is definitely genetically modified (G.M.O.), and almost any chemical may have been used on it, at any time. It is a toxic Frankenfood. Please avoid, and boycott whichever company is producing it.

3: The product is likely genetically modified (G.M.O.), and almost any chemical may have been used on it, at any time.

4: The product was ‘conventionally grown’ with synthetic fertilizers and chemical pesticides. Make note that there is a new generation of pesticides cannot be washed off, because these pesticides are fed to the roots, and infuse into every cell of the plant. These ‘conventionally grown’ foods have approximately 1/10th of the nutritional value of equivalent organic produce, and are significantly less flavorful.

9: This is the highest quality produce, the most nutritious, the most natural, and the most safe. The product is organic (non-G.M.O.), and it was grown without pesticides, synthetic fertilizers, or any chemicals whatsoever. These are truly all-natural. When you see a PLU number beginning with 9, think purity and extremely high nutritional value. For example, an apple with a PLU of 9 will usually be more nutritious than a bowl of PLU 4 spinach.

From: http://worldtruth.tv/how-to-i-d-genetically-modified-food-at-the-supermarket/, original source http://www.plantea.com/genetically-modified-foods.htm

For conventionally grown fruit, (grown with chemicals inputs), the PLU code on the sticker consists of four numbers. Organically grown fruit has a five-numeral PLU prefaced by the number 9. Genetically engineered (GM) fruit has a five-numeral PLU prefaced by the number 8.

For example:

A conventionally grown banana would be: 4011

An organic banana would be: 94011

A genetically engineered (GE or GMO) banana would be: 84011