Here are the basics of what you should know:
- If there are only four numbers in the PLU, this means that the produce was grown conventionally or traditionally with the use of pesticides. The last four letters of the PLU code are simply what kind of vegetable or fruit. An example is that all bananas are labeled with the code of 4011.
- If there are five numbers in the PLU code, and the number starts with 8, this tells you that the item is a genetically modified fruit or vegetable. Genetically modified fruits and vegetables trump being organic. So, it is impossible to eat organic produce that are grown from genetically modified seeds. A genetically engineered (GE or GMO) banana would be: 84011
- If there are five numbers in the PLU code, and the number starts with 9, this tells you that the produce was grown organically and is not genetically modified. An organic banana would be: 94011
Incidentally, the adhesive used to attach the stickers is considered food-grade, but the stickers themselves arent edible.
The Produce Marketing Association in fact created a five-digit numbering system for price look-up numbers for genetically modified produce beginning with the digit 8, just in case some company should want to keep track of genetically modified produce in their inventories.
In fact, many companies have stopped shipping produce to the state of Vermont, which requires identification of genetically modified produce and seeds by use of the code. Produce wholesalers prefer to avoid the question of which vegetables and fruits may have been genetically modified. And there are only three vegetables and one fruit in the American market that are actually GMO:
Papayas from Hawaii (but not papayas from any other source),
Some sweet corn
Almost all yellow squash and zucchini, which were genetically modified in the early 1990s to give them resistance to a mosaic virus that causes green mottling on their skin.
Produce that is labeled as organic cannot include any intentionally added genetically modified ingredients. An organic farmer is not prevented from calling sweet corn organic even if pollen from genetically modified corn plants blew in from other fields.
And what about checking the produce code for the 9 to indicate it was organically grown? American companies are not using this convention, either. The code 4129, for instance, is used both for conventionally raised Fuji apples and for organic Fuji apples. Certified organic produce is labeled in words reading certified organic, and you can also tell by the price.