sweet-potatoesBy Barbara Kessler

With Thanksgiving and the winter holidays upon us, we’re continuing our guide to the potential  chemical and genetic engineering hazards in the holiday feast.

We looked at the Turkey (and faux turkeys) in Part 1. Now on to the veggies! One bright spot about vegetables is that medical research continues to verify the power of eating veggies in protecting against illnesses, even cancer.

Another positive when it comes to side dishes: Most fruits and vegetables, unlike the grain crops such as corn, soy and canola, are not genetically modified — yet. Biotech firms are working to change that, with plans to tinker with a great many veggies.

Sweet corn, for instance, was untouched by genetic modification even as its cousin field corn varieties were completely re-engineered to resist pesticides or produce their own pesticides. But now even sweet corn has now been genetically modified and appeared on the market just this year (2012). (See more below).

Even apples are on the list to go GMO. There’s an application pending to produce an apple that is genetically designed to not brown when cut. One argument against this “Arctic Apple” is that people won’t know when it’s passed its prime.

Genetic modifications of our foods are happening so rapidly that several groups have organized opposition to slow or stop these developments, citing the need for more study and precautions to protect public health, though biotech firms and U.S. government agencies maintain these foods are “substantially equivalent” to non-GMO crops.

Several food and environmental advocacies formed a coalition called “GMO Inside” this month to inform the public about GMOs (genetically modified organisms). Coalition members believe that Americans have a right to know what is in their food, and that GMO foods “have not been adequately tested for human consumption.” Its members include: Food Democracy

Now!, Green America, Institute for Responsible Technology, and the food manufacturers, Nature’s Path Organic Foods and Nutiva, and food activist Vani Hari.

For Thanksgiving, GMO Inside released a list of packaged foods that are likely, based on their labels, to contain genetically modified ingredients, along with alternative organic products that won’t contain GMOs.

Another group working for disclosure about GMOs is the Non GMO Project, which labels non-GMO foods and products.  You can browse their list of verified Non GMO foods here.

Here’s a look at how GMOs as well as pesticides are likely to affect typical foods on the Thanksgiving table:


Whipped, scalloped or baked, potatoes are almost certain to turn up at the typical American feast. Fortunately for people concerned about genetic modifications, the Bt potato, which was modified to produce its own pesticide using a naturally occurring bacterium, is no longer in use in the U.S.. This biotech wonder of the 1990s was so effective at exuding toxic Bt in its leaves that potato beetles, being continually exposed, developed an immunity. Essentially, the experiment backfired.

These early “super bugs” were a major reason  Bt potatoes were driven off the U.S. market in 2000, and even though this experiment presaged the problem of producing super weeds, a major issue now afflicting GM corn and soy crops, biotech marched forward with other pesticide-producing plants and many more designed to resist pesticide applications.

So today’s potato is GM free, most likely. But it’s not pesticide free. White potatoes are typically treated with several applications of insecticides. The USDA testing has found traces of  the pesticides imidacloprid and o-phenylphenol (on 23 percent and 12 percent respectively) on potatoes, according to the Pesticide Action Network (PAN) report “What’s on My Food?”.  Imidacloprid is toxic to bees, and o-phenylphenol  is a known carcinogen.

Potatoes also are treated with a chemical, chlorpropham,  after they’re harvested. Chlorpropham inhibits sprouting and allows the tubers to be stored for longer. This chemical has been tested by the EPA for toxicity, though not since the 1990s, and presumably is safe at the residue levels we’re consuming. But, it does leave you questioning that old saw about eating the peeling because it’s full of vitamins.

We’re also left to wonder how harmful sprouting would be, if it meant that potatoes could skip this additional chemical application. Here’s a cute video about a child, who had similar questions after she discovered potatoes have an invisible chemical veil.

Solution: Buy organic, or buy local.  Domestic potatoes grown in the US were found to have lower pesticide residues.

Solution 2: Peel, and cross fingers that pesticides don’t penetrate the skin.

Sweet Potatoes

These fared better in the toxicity tests conducted by the USDA and reported by Pesticide Action Network (PAN).  Testers detected the pesticide Dicloran on about 40 percent of the potatoes, but this chemical is only listed as a “possible carcinogen.”

But about 4 percent of the sweet potatoes tested turned up with DDE p,p, which PAN lists as a known carcinogen that’s also a suspected hormone disruptor and a toxin that can affect the development of children and reproductive functions. Not so sweet.

Solution: Buy organic, or pass the 4 percent with toxic DDE residues to someone else at the table. (We’re kidding!)

Green Beans

Get ready bean lovers, the news here is not heartening. Seven pesticides turn up on more than 10 percent and up to 28 percent of beans sampled. The list includes Acephate, which is listed as a neurotoxin, suspected hormone disruptor and possible carcinogen, and Methamidophos, also a neurotoxin and toxic to bees, according to PAN .

Can you wash these pesticides off? Perhaps. Rinsing with a vegetable wash might also help. Also, as with the potatoes tested, the organic samples of green beans tested were pesticide free.

Solution: Buy organic, if you can find them. Wash well if you can’t.


Genetically modified corn, along with soybeans, has swept the market in the past 15 years. Today at least 85 percent of the corn grown in the U.S. is genetically modified. The majority of this corn is grown for livestock feed and for products like high fructose corn syrup. It pervades the food system unlike any other food, other than GM soybeans, which comprise more than 90 percent of the market. You can consume these in a panoply of packaged foods, which contain soybean oil or soy protein.

Until recently, the corn we ate directly, the stuff that’s found in freezer bags and sold on the cob, was not genetically modified. “Sweet corn” was still natural. That is, until this year. Enter Monsanto, whose genetically modified sweet corn, engineered to resist the pesticide RoundUp (made by Monsanto) and to produce its own pesticide (the Bt toxin) rolled into production in 2012. The GMO Project estimates that 40 percent of the sweet corn  sold in 2012 was GM RoundUp Ready corn.

Is this corn harmful to human health? Monsanto says no. Food advocates say, we don’t really know, because there have been only short term tests on lab animals, and not enough of that testing.

Until we know more, however, the consumer is forced to play corn roulette, because there’s absolutely no way to tell if the sweet corn you’re buying is genetically modified, or not — unless of course you buy organic sweet corn. Organic corn must be free of GMOs to receive its certification.

The cautious approach: On packaged foods, look for corn flour and corn starch, an indication that GMO corn is likely part of the recipe. For corn itself, buy organic.


Cranberries come to the holiday table as a non-GMO product. But they are grown with a variety of pesticides.

What’s on my Food? reports that the latest testing (in 2006)  found traces of chlorothalonil, 1-Naphthol, Azoxystrobin, Acephate, and chlorpyrifos among other chemicals on cranberries.

Consumers shouldn’t have to be chemists to judge the safety of their food and should be able to rely on regulators. For the record, the regulators — the EPA, USDA and FDA, which all have a hand in approving pesticides on foods — have approved these chemicals.

But how much pesticide residue is harmful remains a science of guesstimates. An article by the Rodale Institute points out that one chemical used in cranberry bogs, chlorpyrifos, is an endocrine disruptor that can have effects on human hormone systems at lose doses.

If you want to opt out, buy organic. Cranberries grown organically are even available in the popular jellied version, a holiday comfort relish that some people seem to consider as vital as the turkey.

Cranberries are a powerful antioxidant, so eating them is beneficial. And when it comes to fruits and vegetables generally, most experts say eat these foods for the vitamins, nutrients and healthy calories they provide, even if you’re buying conventional.