You Asked: Is the video about a young girl’s experiment purportedly showing the dangers of a chemical used on sweet potatoes scientifically sound?

Science Project videoYou asked about a video floating in cyberspace that describes a little girl’s project purporting to show the risks of conventional produce.

Here is my take:

To be sure, the video on YouTube has impact. The curtain goes up on a sweet little girl who is preparing to share with us the results of a science experiment that was supposedly suggested by her grandmother. She shares the spotlight with three sweet potatoes that have been immersed in water to see how they would sprout. The results are dramatic. The sweet potato purchased in a conventional grocery store failed to sprout even after weeks, while the organic potato purchased in the same store produced some scrawny vines. But it was the sweet potato bought in a store that specialized in “organic” produce that steals the show. It practically grew a forest of vines. How could this be? The produce manager in the supermarket had an explanation. Conventional sweet potatoes are sprayed with a chemical called chlorpropham to prevent sprouting. The organic ones in the supermarket may have picked up some of the chemical by cross contamination while the potato from the organic market was free of the chemical. “Chlorpropham can kill animals that they have tested it on. It can also cause tumours,” our little host informs us. She goes on to say that “with all of the chemicals, it is no wonder so many people are getting diagnosed with cancer.” The video ends with the rhetorical question “which potato would you rather eat,” and an ear to ear smile? Point made. Stay away from conventionally grown sweet potatoes because they harbor toxic chemicals.

There’s no way to know how this video really came about. Is it just an interesting little science fair project as it seems, or is there some other agenda? Did someone want to promote an organic philosophy either for economic or ideologic reasons? Let’s explore the real science here. Sweet potatoes are indeed sprayed with chlorpropham, or Bud Nip as it is commercially known. That’s because sprouting is not a good thing. When the sweet potato sprouts nutrients flood into the sprouts and cause the tuber to wither. Of course there is an economic angle here as well. By preventing sprouting, chlorpropham extends the shelf life of sweet potatoes. But what about the claims of this chemical killing test animals and causing tumours? Yes, that happens at monstrous doses. Almost any chemical tested will cause some catastrophe at some dose. That’s why regulatory agencies determine the maximum dose at which no effect is seen in test animals known as the No Observed Adverse Effect Level, or NOAEL, divide this by an added safety factor of usually one hundred and come up with a dose to which people can be regularly exposed without consequence. But regulatory agencies also require ground water testing, effect on fish, effect on livestock, effect on workers who are exposed to the chemical and documentation about residues on produce.

The process to “register” a chemical for agricultural use is not a haphazard one. A great deal of work goes into determining safe levels for humans. And the amounts found on sweet potatoes are way way below any level that would pose a danger. So our little friend’s demonstration really shows the effectiveness of a chemical at preventing sprouting in order to improve the quality of a sweet potato rather than some sort of implied danger from eating conventional sweet potatoes.

Joe Schwarcz

*Link of the Video:

10 Responses to “You Asked: Is the video about a young girl’s experiment purportedly showing the dangers of a chemical used on sweet potatoes scientifically sound?”

  1. Steve Savage says:

    Actually, there are not sprout inhibitors used on sweet potatoes. If they are properly “cured” and then stored under appropriate conditions, sprouting should not be an issue. The student was mislead.

    Chlorpropham (CIPC) has been used safely for over 50 years in regular potatoes (not related to sweet potatoes). There is; however, a new alternative first approved in 2013 that may replace CIPC in spuds.

    Sprout inhibition is key in potatoes. Organic growers use clove oil for this, but because it is less effective they have to gas the storage with it 5-8 times over the storage period. The new option is a naturally occurring chemical, but it has to be made synthetically to make enough. Whether that will be allowed in organic is up in the air right now

    • Lynn Johnson says:

      Mr. Savage, how do you know that sprout inhibitors aren’t used? Please cite your source.Why was Joe Schwarcz say they are?

      Further, have you replicated the little girl’s experiment?

  2. Lorne says:

    The FDA does test organic and inorganic chemicals to see if they will kill you. However they do not and are no mandated to test for cumulative poision. This is the phalacy of toxins in our world. The toxins that are present will inhibit our health over time, long periods for some and shorter for others as we are all a bit different in how our bodies remove these toxins from our system.

    Our bodies do store toxins in fatty tissue and in between connective tissue.

    Yes, everything is a chemical. Silly to even discuss this. We are using the word chemical here to describe inorganic compounds that were made by scietists in a lab using toxics.

    • Kevin T says:

      I have always wondered if there is any testing for toxic interactions. Let’s say alar and chloropropham, and add in pesticide residue. Are combinations such as these tested together to see what they do to the body?

  3. Morris says:

    Thanks for posting this. I’ve been thinking a lot about the use of chlorpropham (Bud Nip) since I resently discovered it’s use on potatoes and have a few problems.

    1) The use of Chlorpropham is not “common knowledge” or is it listed on treated potatoes or other produce. The general public “expects” produce to be unadulterated. Why not add this to the label? “Sweet Potatoes: Now with BudNip to protect nutrition and longevity!” Honestly, it would scare people away from an otherwise excellent source of nutrition. Labeling is especially important since chlorpropham is an “active ingredient” in stored tubers (see below).

    2) Unlike other herbicide/pesticide use designed to be active in the field (chlorpropham is also used in this way as a pre-and post-emergent herbicide) the use of chlorpropham as a sprout inhibitor is active in storage, during sale, and in the household. It’s not a residue with little to no current biological activity, its a biologically active ingredient at the time of consumption. While your argument that it is at a safe level can be made, why use it if there is an easy method to prevent sprouting?

    3) Properly stored tubers should not require the use of sprouting inhibitors. Below 45 degrees Fahrenheit sprouting is inhibited. This is the real benefit of tubers, they can be stored overwinter without lost of nutrient. Why use a chemical for a process that can be controlled naturally? Because it’s finacially advantageous to the distributor, and the companies promoting the use of bud nip. The US government is also culpable in promoting this “cheap and easy” way of storing potatoes and maintain profits for farmers. But this is a shortsighted view. With the advanced technology available in our storage and distribution systems we can easily overcome the sprouting problem with properly stored produce in climate-controled environments.

    4) The nature of chlorpropham activity is especially susceptible to the combined effects with other chemicals we are exposed to. There is currently a dearth of research into the effect of combined chemicals on biological systems. However, some studies have shown that the effects are not additive but multiplicative. At higher doses chlorpropham adversely effects the liver and kidneys causing congestion. This could decrease the effectiveness of the liver to decontaminate the body of other toxic chemicals both naturally produced within the body and from environmental sources. The use of chlorpropham as a pre-emergent points toward the biological effect on cell with high turnover rates (liver and blood cells were most susceptible in higher dose studies). I would welcome increased funding for this type of research.

    In the end, why use it when properly stored potatoes don’t require it? Would not using it increase the cost of conventional potatoes? It likely would. And would that put the cost of large-scale industrial farmed and distributed potatoes on a more equal footing with local, organic produce? Let’s hope so.

  4. CJ says:

    Lisa (and the other commenters), one cannot prove a negative. If there is a claim that a certain chemical causes a disease, that can be researched, and evidence can support it or not. But one cannot prove no effect. The reason (or one of them) is that any lack of effect could be because there is no causal connection, or it could be because there’s a problem in the methodology failing to uncover the connection. It’s extremely difficult to know if all possible confounds have been accounted for, and for something as complicated as the food chain, it’s even harder. It IS possible to research if something has an effect, but not that it has no effect.

    So what should we do? It depends a lot on your overall beliefs. For instance, if I were to claim “I am going to refuse to eat sweet potatoes because I think brown-red dirt causes cancer, and these sweet potatoes were grown in brown-red dirt,” you would (rightfully) laugh at me, or at least try to point out that my fears are irrational. I might say, “have you done a study over 10-20 years showing that brown-red dirt is safe for sweet potatoes grown for humans?” Well, no. But there’s no reason to do so.

    To this argument, I suspect you might say, “but chemicals are nothing like dirt.” To which I respond, that everything is chemicals. Water is the scary-sounding dihydrogen monoxide. We are made of chemicals. The fact that something is a chemical does not make it automatically dubious any more than one dog that attacks someone means that every dog should be eradicated. Every single thing you ingest harms you in sufficient dose and every single thing you ingest is safe in a small enough dose.

    You ask a great question, which is, “how much chlorpophram is safe?” Our best answer is right in the blog post itself and is termed the “No Observed Adverse Effect Level”. At that level, we have no evidence it causes harm. There’s an actual answer to that question, and that’s what the testing and certification is supposed to answer.

    ‘Amazed’ brings up the question of eating extremely large amounts of sweet potatoes over years. First, remember that your body has lots of mechanisms to remove traces of chemicals that it cannot use, so the odds are very high that your body is taking care of the issue. I do agree that cumulative effect is something that SHOULD be accounted for, and probably is, when calculating safe levels. Perhaps the blog poster can let us know how that’s handled.

    It might be useful to publish this information if it was understandable to the non-chemist. For instance, “you would have to eat 84 servings a day of treated vegetables to have an effect”, or whatever the number is. However, the number of people who would really need that information is probably pretty low. Many people would respond, ‘I won’t eat anything that can harm you in 84 doses’, but everythign harms you in sufficient doses. There was a woman last year who drank something like 10 liters of soda a day and got sick, but very few of us need that warning.

    I do agree with the other commenters that the FDA could always use more funding and that we should be careful that it’s always focused on the consumer rather than the producer who has a financial interest rather than a health interest. I also agree that if there are agreicultural workers who are actually getting too high a dose of certain chemicals — and it’s actually researched, not guessed — then that’s a good reason to limit certain chemical usage, and I should refrain from buying items with those specific chemicals.

  5. Amazed says:

    I’m 58 y/o, I have eaten thousands of sweet potatoes, in addition to, the carrots, green beans etc. In your terms, what constitutes “monstrous amounts” ?

  6. Terry says:

    When the FDA says something is safe for consumption it should Always be cause for complete suspicion. The FDA is a totally untrustworthy organization, tucked neatly and safely in the pockets of the food and chemical industries.

  7. Thomas says:

    Nice reply Lisa.
    First: you state “The organic ones in the supermarket may have picked up some of the chemical by cross contamination…” Contact? You mean someone touched it and then touched the organic one? Or they bumped against one another? Is that all it takes to transfer enough residue to kill off life/growth potential? So what does that say about the chemical? Remember, it is on FOOD ready to be handled/ingested?

    You write of these chemicals needing huge doses to cause cancer (you haven’t noticed friends and neighbours of all ages dropping like flies?), but you do not speak of bio-accumulation or the synergistic effects of hundreds/thousands of chemicals encountered through our lives. Nor do you mention that migrant farm workers have the 3rd most dangerous job in North America (~1000 die each year directly from pesticide exposure).

    With regards to your faith in testing: i don’t know if you read the news much but i would hazard to guess that if you Google “contamination of US water supplies” and began reading, you could never finish, ever. And as for regulatory agencies, with cutbacks, gag orders and ever-growing corporate influence over government bodies, plus thousands more chemicals out there than they have even tested, let alone regulated, plus the effects of chemical recombination, your argument is old and totally lame.

    In closing, if there is anyone here with “another agenda”, it is clearly you with your ‘blinded by science’ faith. Science is necessary, but so is common sense.

  8. Lisa says:

    I appreciate your thoughtful response. While it is certainly possible that this little girl (or more appropriately, her grandmother) has an agenda, it is also possible that this just happened to be a science experiment. I’ve done many over the years with my kids and some of the results have been surprising. Either way, I don’t think it really matters. The video is out there, agenda or not, and it shouldn’t be dismissed unless proven to be totally false.

    Unfortunately, I admit to not having a great deal of trust in the FDA. Because they have deemed this chemical safe for human consumption doesn’t necessarily give me the warm fuzzies. The chemical has been shown to cause cancer and tumors in rats when taken in large doses. It doesn’t look like they have studied humans ingesting this chemical in normal amounts over many years. If they have, I haven’t been able to find the results. Don’t forget, we aren’t just talking about sweet potatoes. This same chemical is used on many other fruits and vegetables. If you happen to eat a lot of fruits and vegetables that are sprayed with this chemical, can you say with 100% certainty that there won’t be any ill effects after 10 or 20 years? You can’t because it has never been studied. That’s the problem with testing. The FDA determines that it does cause cancer in rats in large doses and then they determine a “safe” amount for humans. What is a safe amount of cancer causing chemicals one can ingest? Is there a safe amount of nicotine one can take in? Don’t forget, there are plenty of other chemicals on the market that have been deemed safe for human consumption, but cause cancer in rats in high doses. Isn’t it possible that through our daily eating we are taking in these approved chemicals in pretty large quantities and we may be causing harm? Agenda or not, it seems like it is time to address our reliance on chemicals in our food chain.

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