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Thursday, May 22, 2014

Are Organic Apples At Risk of Being Redefined As Contaminated?

An Apple Orchard In Bloom

There is an interesting new "GMO" apple nearing approval in the US and in Canada called the "Arctic Apple."  It was developed by a British Columbia, grower-based organization called Okanagan Specialty Fruit.  Certain genes in these apples are turned off so that the fruit doesn't  express the enzymes that make the apples turn brown after cutting.  You could slice the apples, put them in your lunch or your kid's lunch, and they would still have full flavor, vitamins, and color when it was time to eat them.  I think this is a useful, consumer-oriented trait. Predictably, there are opponents for this sort of scientific innovation.


An Arctic Apple on the right has not browned like the unmodified apple on the left

I've written before about this issue before, but in this post I want to specifically address a particular objection to the commercialization of this technology - the concept that the growing of these "GMO" apples could put the local organic apple industry at risk of becoming "genetically contaminated." I absolutely agree that the organic industry is at risk, but not from the Arctic Apples.  They are at risk from this new definition of "contamination" driven by the "defenders" of organic, which would unintentionally classify all organic apples as being particularly "contaminated."

The "contamination" scenario is based on the potential movement of pollen from flowers of the Arctic Apples to apple flowers in organic orchards.  It is useful to consider this from a biological perspective.

Plant Sex

A Honey Bee Doing Its Normal Job in an Apple Flower

What we are really talking about here is not a new phenomenon associated with a "GM Crop."  This is about normal plant sex.  Apple flowers are not "self-fruitful" meaning that for an apple flower to be successfully fertilized, the pollen has to come from a genetically distinct apple -  usually carried by a bee.  One efficient way to foster this DNA exchange is to graft some branches of crabapples onto some of the trees in an orchard or to simply grow some crabapples within the orchard.  The bees visit those flowers and carry the pollen to flowers of the desired variety. The only part of the resulting apples that contains the DNA from the crabapple is the embryo portion of the seed.  All of the rest of the apple that we eat only has the genes of the intended variety. Thus, even though apples might be pollinated from marginally edible crabapples, we have never considered them to be "contaminated."

If Arctic Apples are commercialized in BC (or anywhere), there might be some small percentage of seeds in other varieties that would be pollinated by a bee that moved between the two types of orchards.  As with the crab apples, but at a vastly lower incidence, there will be the DNA from the arctic apple, a tiny part of which has been changed to prevent expression of the apple genes for browning.  Someone would have to intentionally sample lots of apple seed using very sensitive lab techniques to find this.  If that sort of DNA in seeds is redefined as "contamination," then all apples are contaminated with the DNA from a different apple variety or a crabapple.

But What About The Seeds?


The only thing that could be "scary" about the apple seeds with the Arctic Apple DNA is the same thing that is "scary" about all apple seeds.  They are "cyanogenic" meaning that if chewed, they produce hydrogen cyanide. You would have to eat a lot of apple seeds to be affected, but apple seed consumption is a non-issue for any normal sort of consumer.

The next important thing to know about apple trees is that they are not grown from seeds.  Almost no fruit crops are grown from seed because what you will get will not be the desirable variety you started with, but usually a much inferior type that results from the cross of two different lines. The apple varieties we eat are always "cloned", meaning they are reproduced by grafting - not seeds. Long ago some apple seeds were used to make root stocks, but in modern orchards (including organic), the growers use cloned "dwarfing rootstocks" so that their trees can be kept in a size range that is much safer and more efficient for harvest.  So just as it is no problem to grow many distinct apple varieties in the same area, there is nothing newly problematic about adding Arctic Apples to that variety list.

But What About the Bacterial or Viral DNA?

In the process of genetic engineering, there are some sequences of DNA from a bacterium and from a virus which end up in the modified plant. The bacterium in question is called Agrobacterium and it is nature's own genetic engineer.  It makes a circular bit of DNA called a plasmid which it uses to get some genes inserted in plants it infects. We use a "disarmed" version of that plasmid so a little bit of Agrobacterium DNA is in the modified plant, but it is not "expressed" meaning that no proteins are made based on that DNA.  That DNA has been a part of most GMO crops for a very long time without any issues, but if the presence of bacterial DNA is going to be called "contamination," the there will be a problem with every apple we eat, not just the seeds of some of them.

Why You Get Bacterial DNA With Every Apple, And More From Organic


You may have heard about "microbiomes" which are communities of bacteria and other organisms that inhabit everything from our intestines to our skin.  On plants there are similar microbial communities we call epiphytes (living on the plant surface) and endophytes (living among the plant cells).  All apples have abundant bacterial populations of this nature with all of their bacterial DNA - not just some tiny fragment as in the modified apples.  If that presence is going to be defined as "contamination" then every apple everywhere is contaminated with bacterial genes!

For apples in general, and for organic apples in particular, there are widely used, very safe biological control agents which are based on whole bacteria and thus include the DNA of bacteria.  Bt sprays are based on the bacterium Bacillus thuringiensis and are commonly sprayed on apples to control caterpillars.  There are biocontrols to suppress apple diseases based on the bacteria Bacillus subtilis and Bacillus pumilus.  These products are often sprayed on organic apples.  In these cases we are talking about the full compliment of bacterial DNA expressing the bacterial genes.  If bacterial DNA introduced by human activity is defined as a contaminant, then all apples are "contaminated," particularly the organic ones.

There is also a specific piece of virus DNA in an engineered plant like the Arctic Apple, and it has been raised as a "contamination issue."  That piece is called a promoter and it is what turns on the gene that follows it in a DNA sequence.  Again, that promoter in the embryo of an uneaten seed is a functional non-issue, but it is certainly not the only viral DNA on or in an apple.  There are viruses called phages present in some of the bacteria that live on the plant.  However, none of this even compares to the amount of virus (with its DNA) that is quite intentionally sprayed on apples. There are biocontrol products, also approved for organic, based on Cydia pomonella granulosis virus. This is an agent which infects and kills the larvae of the codling moth - one of the biggest pests of apples.  The growers use these viruses as part of an integrated pest management system, but by the new definition being promoted, that means "contamination."

The Organic Precedents For This Sort of Issue


If there is ever any problem for organic growers because of the commercialization of the Arctic Apple, that injury will be entirely self-inflicted by the wing of the organic community that makes the rules.  It will be the result of a state of mind, not any rational risk.  It will also go against well-established precedents for organic.  The USDA Organic rules allow for a degree of "unintentional" contamination of organic produce with synthetic pesticides.  The same is true for fertilizers.  In California there were two historical instances where companies were "spiking" an organic fertilizer product with "synthetic nitrogen." For some time, a majority of California organic growers were using such products.  When the fraud was exposed, none of the farms that had used that fertilizer lost their organic status or had to go through the three year transition again.  It was ruled to have been unintentional.  Why wouldn't the same logic be used for the "unintentional" presence of a tiny bit of harmless DNA in a few apple seeds we don't eat or plant?

The organic apple growers of British Columbia are not threatened in any rational way by the potential commercialization of genetically engineered apples.  The only threat comes from those who want to re-define genetic contamination in a way which makes no practical sense.  This doesn't serve the interests of consumers, nor does it really serve the interests of the organic growers.

Honey bee on apple flower image from Wikipedia.  Arctic Apple image from Okanagan Specialty Crops.  Apple orchard image mine.

Disclaimer:  I am not employed by Okanagan Specialty Fruit in any way.  My opinions on this topic are my own.

You are welcome to comment here and/or to email me at savage.sd@gmail.com.  My speaking website is DrSteveSavage.com.

Monday, May 12, 2014

Why You Can Feel Guilt-free Buying Non-Organic Produce





There are several different reasons people are willing to pay more for organic produce, but many consumers do so believing that it is a way avoid pesticide residues.  That widely held belief is unfounded.  Here is why:
  1. There are definitely pesticides used in the growing of organic crops.  There are residues of those materials on the harvested products.
  2. Residues of synthetic pesticides are also frequently found on organic produce, even though they are not materials that are approved for use on organic.
The reason I feel the need to challenge the "avoid pesticides via organic" myth is that it causes many consumers to feel unwarranted marketing and peer pressure to spend more for organic. The guilt tripping is particularly intense for moms.  The not-so-subtle message is, "if you really cared about your family or your health, you would spend the money for organic."  Whether this leads people to spend more than they should, to buy less total produce, or just to feel bad, it is a destructive outcome based on disinformation. Yes, there are low level pesticide residues on both categories of produce, but in neither case should those residues dissuade you from enjoying all the health benefits that come with eating lots of fruits and vegetables.

Residues of Organic-Approved Pesticides on Organic Produce


Anyone who has ever gardened realizes that there are plenty of pests out there that like to "share" the plants we grow for food.  There is no magic feature of organic that gets around this biological reality, and so there is an extensive list of pesticides that can be used by organic farmers. That list is not based on safety, but rather on whether the material is considered "natural." "Natural" does not automatically mean "safe." Indeed, some of the most toxic chemicals known come from nature. The organic-approved pesticides still have to be registered with the EPA because it is that agency's job to insure that these materials can be used in ways that are safe for us and safe for the environment.

Some organic approved pesticides are very benign (low hazard) materials, but so are a great many of the synthetic pesticides used by conventional farmers.  Some organic-approved pesticides are slightly to moderately toxic. This is also the case for synthetics.  There are many pesticides that are used by both conventional and organic growers.  Some of the pesticides commonly used on organic crops are applied at rather high rates (pounds per treated acre).  Some are approved for use until almost immediately before harvest.  In any case, organic-approved pesticides definitely leave residues on treated crops by the time they reach the consumer.

Synthetic Pesticide Residues on Organic Produce

Occasionally, government agencies intentionally conduct specific surveys of organic produce to check for residues of non-allowed, synthetic pesticides.  The Canadian Health Authority did this in 2011/13 and they found synthetic pesticide residues on 46% of the organic produce samples.  In 2010/11, a similar survey was conducted by the USDA, and they also found synthetics on 43% of organic produce samples. Both sample sets included produce grown in the US, Canada and Mexico. What both of these agencies found wasn't alarming, but it definitely doesn't fit the marketing claims about organic as a way to "avoid synthetic pesticide residues." The presence of these residues does not generally mean that organic growers are violating the organic rules. Some of produce may have been mislabeled. Also, the testing methods are simply so sensitive that they can detect materials that got there unintentionally through something like spray drift or from harvesting or storage equipment.  In fact, the rules for organic have always allowed for the "unintentional" presence of such chemicals.  Buying organic does not mean "no synthetic pesticides."

Should We Worry About These Residues?

Since avoiding all pesticide residues is not an option, the remaining question is "Should we worry about them?"  Are the residues on organic and conventional different enough matter?  The short answer is, "No." Here is why.

When regulatory agencies such as the EPA approve a pesticide for use on a crop, they use all the information they have about that chemical to define an amount of it which can be present at the consumer level without any meaningful risk.  In the US that is called a "tolerance" and in most countries it is called an MRL (maximum residue level).  These thresholds are designed to be very conservative, so that as long as the residues are at these levels or lower, they are about 100 times less than an amount that would be of any concern.  These values are based on an extensive risk assessment based on millions of dollars worth of required testing.  The regulators also restrict how the pesticide can be used (e.g. how long between the spray and harvest) so that any residues left should be below the tolerance.

So whether we are talking about the residues on organic or on conventional, the meaningful questions are:
  1. What is the particular chemical that was detected?
  2. How does the amount of that chemical which was found compare to the crop/chemical-specific tolerance or MRL?
Every year the USDA collects samples of produce, takes it into the lab, and looks for residues of pesticides. They publish the data, and what it consistently shows is that the residues are virtually all below or even well below the conservative tolerances.  Similar data is generated in Canada.  California does additional testing.  The results from these more extensive testing programs are very much like those occasional studies with organic:  yes, there are residues, but no, they are not worrisome.  

Each year, an organization called The Environmental Working Group (EWG) publishes a list that it claims to provide guidance for consumers about which fruits and vegetables have the "most pesticide residues" and thus which are high priority for buying as organic.  In making their list they specifically ignore the data which the USDA provides about the identity of the chemical and about how its concentration compares to the appropriate tolerance.  EWG has never provided any justification for this absurdly non-scientific approach. They also never happen to mention the reality that there are also often pesticide residues on the organic options. The publication of this list is apparently very good for the EWG's fundraising efforts, but it is a huge disservice to consumers. Their "Dirty Dozen List" or "Shopper's Guide" is one of the most egregious examples of the dishonest, guilt-based marketing that puts so much pressure on moms and others.


Just enjoy!


Study after study demonstrate the substantial health benefits of a diet with lots of fruits and vegetables.  That beneficial and delicious produce will come with some trace levels of the pesticides that conventional or organic farmers used to be able to successfully produce the food for your family.  You can enjoy it without guilt.






Just a few links about produce and health:

You are welcome to comment here and/or to email me at savage.sd@gmail.com.  I tweet about new posts @grapedoc.  My speaking website can be found here.