How about finding a lab-synthesized, allergy-causing, poorly-researched DNA strand in your apple?

The scenario is a lot more likely than you realize; or, as it turns out, a lot more likely then major food suppliers want you to realize. Because you don't sit down to dinner and see a turnip that talks, or a potato that glows in the dark, the thought of what happened to your salad before it hit your plate might never cross your mind. But the innocent grains and vegetables that anchor your diet have recently been subject to bizarre experiments in labs across the world.

Food suppliers across the planet are using a process called genetic engineering. But this process doesn't take place in a farm, or in the barn; it all happens in a lab, under an electron microscope. All organisms have a DNA code, located in the nucleus of every cell, that contains the 'blueprint' for that organism. This code comprises many different genes, which contain the different characteristics for the organism -- for example, the color and the texture of the tomato. Genetic engineering involves taking genes from one species and inserting them into another species in an attempt to transfer a desired trait or character. For example, if you wish to grow a tomato that is more resistant to bruising and 'squishing', you can insert a gene from another plant that changes the tomato's outer skin and flesh.

This process takes place inside the cell. The selected gene is located on the DNA strand and clipped out; then bacteria manufacture thousands of identical copies of the gene. The gene is then inserted into the DNA of the other organism. The plant cells that accept the new gene are then selected, and grown into the desired organism. A firmer, more resilient tomato ripens on the vine; is picked and makes it way to market. You go to the grocery store, squeeze the tomatoes, thump the melons, grab some brown rice and go home to cook dinner. You've got a fresh, firm tomato on your plate -- "What's the problem," you ask? "Why are you interrupting my dinner?"

Before you take another bite, you're going to want to hear this. Problems with GE foods arise from three main areas: first, there is a very low success rate for the cells, which actually accept the new gene into their original DNA. The new gene must be monitored in each cell, to see if it has taken hold in the organism. In order to trace which cells have accepted the new DNA, a 'marker gene' is attached to the transplanted gene. This marker tells the scientist which cells have taken the new gene into their DNA. The marker also has been shown to code for a resistance to antibiotics. So, in addition to a juicy blast of cancer-fighting anti-oxidants, your salad may also contain tiny bits of DNA, which will increase your resistance to antibodies.

The second problem is the level of uncertainty that accompanies the entire process: many scientists believe that the process of inserting the gene will cause unexpected complications and disruptions in the changed organisms. Some gene insertions have resulted in the sudden production of toxins which killed the subject plant. Not enough is known about DNA to determine the exact effects you get once you start to change it. The New England Journal of Medicine called genetically engineered foods "uncertain, unpredictable, and untestable." If no one knows what the risks are, then why are people worldwide consuming these things without even being informed that are dangerous effects, both known and unknown?

Some effects, however, can be measured. In 1996, a type of genetically engineered corn called Star Link made it into both animal feed supplies and food products for human use. People eating Kraft taco shells and similar products that contained this corn experienced allergic reactions. Other products, containing genes inserted from Brazil nuts, were pulled before they could reach consumers when deadly allergens were discovered forming in their cell structure. And because GE gives rise to unpredictable results, testing the GE food becomes very unscientific process.

The third problem is the one that affects you every single day. GE foods are not required to be labeled as modified, so you have no way of knowing if what you're eating has been GE. The food industry and even groups like the EPA and FDA are extremely resistant to informing the consumer that he or she is eating a genetically engineered food. The FDA's new policy proposal does not require labeling or any pre-market safety testing of genetically engineered foods. Why aren't we given the choice to eat GE foods or not? If a container of yogurt goes bad in your refrigerator, it's fairly obvious what's happening: the top of the yogurt turns blue and fuzzy; and if you leave it there long enough, it may even reach for you before you reach for it. It's clear what's happened there. With GE foods, there's no sign like this to indicate the change that has taken place.

These products are everywhere -- in the feed that our stock animals eat, in the fruits and meats and processed foods we buy, and even in vegan products like juices and soy-based foods. So, no, you can't use the dangers of GE foods as an excuse to never touch a vegetable again. What you should do, though, is check out the Greenpeace website to see what major food products have been modified, and which haven't. You can talk to the manager of your grocery store to see what the store's policy on labeling the GE products on their shelves, or even pulling these things from the inventory. (Yes, it can happen -- it happened at the grocery co-op where I thump my own melons and squeeze my own tomatoes. GE products were labeled, then removed.) You can look at sites like purefood.org to keep on top of the scientific community's findings on GE foods. Or write to the FDA and EPA and find out what they're doing about researching and labeling these foods -- let them know that you're out there, and you're thinking critically about the choices you make.

Because we cannot yet determine all of the hazards which GE foods present, nor do we have reliable methods to test their safety or estimate the risks of introducing them into the food supply, we must conclude that GE foods cannot be called safe. So you can squeeze the fruit and thump the vegetables, or even the other way 'round -- just don't eat anything that glows in the dark.