GM Foods and PLU Codes

Can PLU (Price Look-Up) codes help concerned consumers avoid genetically-modified foods?


The idea that a 5-digit PLU beginning with “8” is a reliable guide to the genetic characteristics of a piece of produce has spread around the internet like wildfire.

Trouble is, it’s false. Now, it’s a falsehood rooted in fact: the numeral “8” (in the 1st position of a 5-digit code) has in fact been set aside, (by the International Federation for Produce Standards) to designate GM foods. But the code is entirely voluntary, and no one is actually using it.

So, in theory, a 5-digit PLU starting with 8 (if you ever saw one) would imply that the product in your hand is genetically-modified. But the absence of that 8 tells you absolutely nothing at all.

(For a longer version of the explanation, see PLU Codes Do Not Indicate Genetically Modified Produce, by Jeffrey Smith.)

I have just a couple of things to add.

First is that this kind of thing just adds to my concerns about the power of labelling to inform consumers. (See my blog entries, Does it Matter if Consumers Understand Food Labels? and Are Labels the Answer (to Everything)?) But now we see even more reason for concern, if labels that are not aimed at consumers (and that don’t tell them much of anything) are liable to be taken up and misinterpreted.

Second is that the confusion over PLU codes suggests that advocates who are concerned to inform the public should be very careful, not just in gathering facts but also in thinking through the logic of what they’re saying. Part of the problem, here, is that most people are bad at conditional reasoning. The fact that an 8 implies GMO does not logically mean that the absence of an 8 implies non-GMO. Advice for consumers needs to be framed in a way that minimizes both false positives and false negatives!

About Chris MacDonald

I'm a philosopher who teaches at Ryerson University's Ted Rogers School of Management in Toronto, Canada. Most of my scholarly research is on business ethics and healthcare ethics.
This entry was posted in biotechnology, certifiction, ethics, genetic modification, GMO, labeling, organic. Bookmark the permalink.

19 Responses to GM Foods and PLU Codes

  1. Hello,
    you forwarded a comment on my article on Suite 101 entitled PLU Codes and How They Can Help Consumers Avoid GMO foods. I entirely disagree with most of your statements; I have personally checked this out to my satisfaction. I buy from reputable health food stores and their produce always has the 9 for organically grown. I checked the source of some regular grocery store produce with the absence of an 8 or 9 and learned that it was conventionally grown, but not GMO and not organic, of course. I also checked some produce with the 8 and indeed it was from a GMO source.

    Is this the case all the time…of course not. But after factoring in for frauds, it’s a pretty reasonable bet in helping someone avoid GMOs and it’s way better then nothing.

    So, sorry, the tone of your comment and information just doesn’t encourage me to confirm your comment on my article. You are implying that I am entirely misguided and all of my information is incorrect and it is not…I did enough research to see that it can work to pay attention to the PLUs.

    Grace Joubarne

    • Grace:

      I apologize if my tone offended you. But a voluntary label for the use of cashiers cannot be relied upon by consumers. Fraud is not at all the only exception. The food industry (in North America) has been quite generally hesitant to engage in labelling of GM foods. Anyone walking into the average grocery store and saying, “Hey, banana only has a 4-digit code (no ‘8 prefix) therefore it’s not genetically modified” would be making an error. It may or may not be genetically modified, depending on whether the labeller has chosen to apply the voluntary numbering standard.


      • cherry says:

        Got kiwis at Costco store today with itm/art# 83804,does it mean it is GMO? How do you find out? I searched on current GMO foods on the market and did not find kiwi in the list. Where do you find information?

      • I would guess the kiwi you bought was mis-labeled. That number is nowhere near the correct code for Kiwi, which is 4030 (so GM kiwi ought to be 84030 if it were labeled).

        And as far as I have heard, there are NO gm kiwis on the market. See here:

      • I think you may have misinterpreted the presented usefulness of PLU codes for avoiding GM produce. In my experience it has been presented as ONE way to avoid SOME GM produce. Meaning that if you see a five digit beginning in 8 then you know for sure to avoid it, but if you don’t see the 8 it mean you need to do more research. The WikiHow page on avoiding GMOs is pretty clear on this for example. If any Gmo activist were presenting this as a surefire method for avoiding all GMO then yes they were wrong, but that is not how I have seen it presented. Checking the PLU code is merely a “quick trick” similar to vegans checking the cholesterol content of a food, if cholesterol is present vegans know to avoid it for sure, but if it has zero cholesterol it just means to research it deeper.
        I really like your blog and am a bit surprised that you have just repeated Jeffery Smith’s and others propaganda. His purpose in “busting” this pseudo-myth (really just a strawman) appears to be to promote the Non-GMO Project as the preferred alternative, as seen at the end of the article you link to. He is simply knocking down people’s confidence in their ability to do their own research on their own food so that they will support anti-GMO activism.

      • OK, if looking for the 8 isn’t useless, how about “nearly useless?” In practice, though, it depends on how often the 8 is actually used when the produce in question really is GM, and that’s information I just don’t have. (Does anybody?)

        And I’ve definitely seen this presented as a way confidently to figure out whether produce is GM or not — a 4-digit code is described as indicating conventional produce, when really (as you correctly point out) the most it indicates is “go do more research”. Bottom line: looking for the 8 is not very useful.

        And for the record, I have no attachment to or sympathy for Smith’s campaign. I’m just looking at the logic of what the presence or absence of that digit indicates.

  2. M. Davis says:

    Chris, if people are smart enough to even know about a PLU code, believe me, they are smart enough to know the meanings and not get confused about them. It is you, along with Big Ag, and Big Corp who are trying to confuse consumers.
    If GMOs are so great, why not label them? Oh yes, you think we are not educated enough to understand. BAh! Scientists should not give us food we don’t understand – and we don’t want to eat that food. 75 to 90% of people. Where is democracy and our right to know?

    • M.

      I’m not saying anyone isn’t smart. But do note that this misconception about PLU codes is absolutely rampant on the internet, including on websites run by people claiming to be food experts.

      And for what it’s worth, a market is not a democracy. Democracy is how we choose leaders, not products.


      • Have to do as I am told says:

        Democracy is how we choose leaders not products? Leaders = products.
        You mean products talk and vote for themselves, that it’s not the Leaders?

        Unfortunately, they’re in charge and they will always do what they want.

      • Your equal sign is incorrect. The equal sign suggests equivalency. Even if you argue that leaders are a kind of product, the two categories are not ‘equal’. One is a subset of the other. Leaders are a special kind of ‘product’ that we elect. The point remains that a market is not a democracy. All citizens of your country are forced by democratic processes to share a single leader, even if you didn’t all vote for him. That kind of compromise is the heart of the democratic process. In the market you buy exactly the product you want, from among the options on offer, and I don’t have to wear the same colour shirt that you do. (I owe this point to the Nobel-prizewinning economist, Milton Friedman).

  3. LM says:

    I wish there were no such things as GMO products out there. Further more, since there are, I wish they were properly labelled, so that we could avoide them like the plague. Shame be on Monsanto, government departments and others that wish to force us to use their evil products, by deception and cover-ups. We are sick (no pun intended) of thier betrayal, and murder of innocent and unsuspecting people. They should all be charged for crimes against humanity. The way the Creator made the food for us, was declared PERFECT! – And no man can improve on that!

    • LM:

      FYI, almost none of the foods we eat today — or any of the foods we’ve eaten in the last few hundred years — are products of nature (or The Creator as you put it). All of them are hybrids cultivated by humans. That includes pretty much all fruits, vegetables, and grains that have ever been consumed by humans.


  4. Bryant farks says:

    I just wanted to inform you that this article is misguided.
    As described by the international federation for produce standards, in their article on using the PLU system here…

    Click to access IFPS-plu_codes_users_guide.pdf

    They describe the number prefixes in chapter 2 under the heading Fifth Leading Digit Qualifier, as follows…

    “The IFPS shall be responsible for deciding the assignment and definition of qualifying prefix digits for international recognition. At present, only three digits have been allocated:
    0 Applies to all non-qualified produce and is generally presented without the leading
    “zero” digit.
    8 Genetically modified
    9 Organic”
    So if a banana was PLU 4444, the modified banana would be 84444, the organic banana would be 94444 and the conventional banana would be either 04444 or just 4444, the zero digit assumed.

    Perhaps, as you suggest, it would be best to research these matters thoroughly before attempting to teach, yes?

    • Hi:

      If my blog entry were inaccurate, I would welcome correction.

      But nothing in your (snippy) comment contradicts anything in my blog entry. Perhaps you didn’t read it fully?

      I acknowledged what the “8” is supposed to stand for. I merely pointed out something you omitted — namely that USING the 8 is voluntary. Lack of an 8 prefix therefore does NOT reliably indicate non-GM food.

      Please do enlighten me if I’ve misunderstood.


  5. Jamie says:

    Hi Chris.

    Thanks for clearing that up for me.
    I guess I have to be very careful for now about where my produce and meat comes from, and hope that in the future it will be an obligation to label genetically modified products as such.


  6. Les says:

    Hi Chris,

    Thanks for the info. I understand what the difference is between voluntary and non-voluntary, and how it affects the numbers; even if some of the posters here don’t.


  7. Tom Majors says:

    I would say buy organic at an organic health food store and be done with this mass confussion of nothingness info. We all know that conventional and GMO is worthless in nutrition. To be sure what we are getting is safe we must start growing our own and do away with lawn chemicals. We are growing these beautiful lawns with all kinds of chemicals and just looking at them. Why not grow organic gardens and stop supporting the chemical companies.

    • Tom, please! “GMO is Worthless in nutrition”?! That’s an entirely unsupported — and unsupportable — claim. If you can come anywhere close to supporting it, please provide citations.


  8. * correction to my earlier comment
    I meant the Non-GMO Shopping Guide, not the Non-GMO Project. Sorry for the mix up if anyone noticed.

    I can agree with “nearly useless” but more so because of the lack of GM produce on the market than the system being voluntary. The 9 is just as voluntary as the 8, yet many of the same people still put stock into looking for “the 9” because organic produce is more common and there is more of an incentive. Yes its at the bottom of the list of way to avoid GMOs, far below calling the company and asking, but i don’t think it needed busting that bad(again it was more a vehicle for Smith to promote GMO fears and his campaign), it has the potential to be used especially if there is an increase in Gm fresh produce.

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