Can Biotechnology Prevent Foodborne Illness?

Federal public health officials have failed to make any progress in preventing food poisoning from common pathogens during the past several years, according to the U.S. Centers for Disease Control and Prevention.

The incidence of human infections caused by Salmonella,E. coli, and seven other common pathogens was essentially unchanged from 2004 to 2008. During this time, incidents of contamination that involved fresh produce and processed foods, including Mexican peppers, California lettuce, and peanuts, have led to mounting concerns about food safety. “We recognize that we have reached a plateau in the prevention of foodborne disease, and there must be new efforts to develop and evaluate food-safety practices from the farm to the table,” said Robert Tauxe, Deputy Director of the CDC’s Division of Foodborne, Bacterial, and Mycotic Diseases.

Actually, those efforts could, and should, begin at an even earlier stage than the farming of plants. They should include more aggressive use of new technology to make the plants themselves intrinsically safer— an approach which, ironically, is being stymied by government regulators, food activists, and organic food advocates.

Modern farming operations—especially large farms—already use strict standards and safety measures designed to keep food wholesome. And very often they’re highly effective: America’s food is affordable and safe. However, because agriculture is an outdoor activity and subject to numerous random challenges, there are limits to how safe we can make it. Inevitably, there will be acts of God (i.e., biology and evolution), so if the goal is to make a cultivated field completely safe from microbial contamination, the only definitive solution is to pave it over and make a parking lot. But we’d only be trading very rare agricultural mishaps for fender-benders.

Nor can we rely on various links in the supply chain to remove the pathogens from food infallibly. The 2006 spinachbased outbreak of illness, caused by shiga-toxin-producing E. coli which sickened more than 200 people and killed five, demonstrated that package labels such as “triple washed” and “ready to eat” must be tempered with skepticism. Many processors were quick to proclaim the hygiene of their own plants and shunt the blame toward growers, but all of those in the food chain share responsibility for food safety and quality.

In fairness to processors, washing alone will not remove pathogens from produce. The reason is that the contamination may occur within the plant. Bacteria attached to the surface of fresh produce may find their way below the surface of the skin through pores called stomata. Exposure to Salmonella, E. coli, or other microorganisms at certain stages of the growing process may introduce them into the plant’s vascular system. Sunlight and possibly photosynthesis itself may help pathogenic bacteria become internalized by the plants’ cells, making them impervious to washing and the use of food sanitizers.

Technology has an important role—or more accurately, it would have if only regulators, organic food advocates, and other food-faddists would permit it.  Irradiation of food is a safe and effective tool that has been used sparingly, mainly due to opposition from the organic food lobby and to government over-regulation. But as valuable as irradiation is, it is not a panacea. Although it kills the bacteria, it does not negate the potent toxins secreted by certain bacteria such as Staphylococci and Clostridium botulinum.

By inducing the production in vivo of “antisense” ribonucleic acid (RNA), recombinant DNA technology applied to plants offers the potential both to inhibit microorganisms’ ability to grow within plant cells and to block the synthesis of the bacterial toxins. The complement of DNA and RNA strands provides a mechanism to silence genes, including those of pathogens. To silence a target gene, a second gene is introduced that produces an mRNA complementary to that produced from the target gene. These two mRNAs can interact to form a double-stranded structure that is inactive in protein synthesis. Thus, in theory, the presence of DNA that gives rise to antisense sequences could, with a high degree of specificity, inhibit the expression of a variety of bacterial genes, including those that code for toxins.

Unfortunately for plant genetic engineers—and consumers— recombinant DNA technology is regulated in an unscientific, excessive, and discriminatory way by USDA and EPA. Regardless of the risk (or lack thereof) of the product, the technology is subjected to hugely expensive and dilatory regulatory requirements and red tape. Instead of revising regulation to reflect scientific consensus and the vast experience with recombinant DNA-modified plants and foods derived from them, regulators appear to be inclined to increase the stringency of regulation.

Will federal regulators act responsibly and permit science and common sense to trump ideology? Don’t bet the farm on it.