Despite Taco Troubles, Biotech Foods Are Safe

By Dr. Steve L. Taylor
October 26, 2000 The Omaha World Herald

The writer, a University of Nebraska-Lincoln professor, heads UNL's Department of Food Science and Technology.

The events that forced Kraft Foods, and then Safeway, to recall taco shells that contained an unapproved variety of genetically modified corn should never have occurred and should never be allowed to happen again. Federal regulators should never have approved a type of corn for animal feed that was not allowed in human food. And Aventis, the company that developed the corn, should never have continued to bring it to market without full food approval.

It was almost inevitable that some small amount of corn intended for livestock feed would wind up in general commerce and eventually a consumer product. A mistake in handling, misidentification at the grain elevator or even sabotage could result in unapproved grain being commingled with other grain. Even a tiny amount can be detected with modern testing procedures. The good news is that this was a unique situation. The Aventis corn, known as StarLink, was the only genetically modified crop grown in the United States that had not been approved for human consumption. All other biotech crops have been fully approved for food. One hopes that no commodity crop will ever again be allowed on the market without regulatory assurance that it is safe for human consumption.

Kraft has made that specific recommendation, and biotech companies will almost certainly comply voluntarily to avoid further incidents. Aventis, which is faced with spending more than $60 million to buy back all the StarLink that corn growers produced, announced Oct. 12 that it had voluntarily pulled the plug on the product. And the biotech industry has stated that no future product should be allowed on the market without human food approval. So this should be the last time this occurs.

Having said all that, there was virtually no risk associated with ingesting the tacos that contained the unapproved corn. The Environmental Protection Agency had refused to approve food uses for StarLink, which resists harmful insects without the use of chemical insecticides, because tests had not demonstrated that a novel protein introduced into this particular corn would not become an allergen.

StarLink, referred to as Bt corn because it contains a protein from the soil bacterium Bacillus thuringiensis, is different from all the other Bt corn products on the market. All the other Bt corns, which are fully approved for food usage, contain a Bt protein known as Cry1.

StarLink contains a Cry9 protein. The crystalline protein, known as Cry9C, does not resemble known allergens, so in fact it may not be an allergen. However, Cry9C was not immediately broken down in digestion tests. Because most food allergens are not readily digested, the EPA wanted more data before concluding that the protein would not become an allergen. On this basis, the agency was correct in denying the food use. That should have been the end of the matter, but of course it wasn't. Feed use was approved. Nevertheless, even if the Cry9C protein is an allergen, its low-level presence in the recalled taco shells would pose virtually no threat. In order for people to have an allergic reaction to any protein, they must be exposed to it multiple times over an extended period until they become sensitized. Even people who develop allergies to known allergens such as peanuts or wheat do not have an adverse reaction upon first exposure. Also, people must be exposed to a fairly high dose. It is virtually certain that any Cry9C protein in foods, if present at all, would be at extremely low levels.

This has not stopped anti-technology activists from spreading alarm and implying that biotech foods are unsafe. Biotech foods are rigidly tested, with special emphasis given to assessing allergenicity. The other Bt products on the market have passed allergenicity screens, and no food use is allowed until tests show that the biotech-produced crop is equivalent to or as safe as its conventional counterpart.

Current biotech products allow farmers to increase yields and reduce their use of chemical pesticides. In the future, biotechnology will offer extensive food benefits, such as better nutritional content, less spoilage or even peanuts and wheat with their naturally occurring allergens removed. For these benefits to occur, the public must have continued confidence in our regulatory system. That means no more feed-only approvals so mistakes like this won't send the wrong impression to consumers. Taylor was chairman of an international panel of scientists formed by the Food and Agriculture Organization and the World Health Organization to construct model approaches to assess the safety of genetically modified foods.