Food Safety: Is It Worth the Worry? Determining Risk

by Food and Drug Administration (FDA)

Of the many health concerns challenging the public trust in recent years, food safety looms large. Pesticide use is the issue most familiar to many of us, but recent news stories reflect a multitude of other worries: dioxin leaching into milk from paperboard milk containers; lead in ceramic products leaching into food; Salmonella bacteria in eggs causing outbreaks of illness; color additives banned for possible carcinogenicity (cancer-causing ability); and possible risks from hormones given to cows to increase milk production. These are but a few issues raising the level of public concern and confusion.

Consumers are not alone in their frustration. "Scientists, managers and regulators who study risks for a living are constantly dismayed because the public seems to worry about the 'wrong' risks," says Robert Scheuplein, Ph.D., of FDA's Center for Food Safety and Applied Nutrition. He notes, for example, that "for several decades, food and color additives have topped the list of perceived consumer risks among the substances FDA regulates, despite the view of FDA and other professionally qualified groups that objectively they belong at the bottom."

What Is "Safe?"

Just what substances in foods do or do not pose a safety risk, how are the risks assessed, and how should they be managed? These are the questions with which government agencies, special interest groups, and consumers continue to grapple.

Remarkable advances in scientific knowledge and technology over the past half century have heightened public expectations for a risk-free environment and quick solutions to public health problems. But these very same scientific advances have raised new questions that confound how we are to define what is "safe."

A 1949 FDA monograph stated: "A substance proposed for use in foods should show no chronic toxicity in animals in an amount equivalent to 100 times the proposed human use level, i.e., a safety factor of 100 should be present." Thus, the safety standard for a substance was set to be at least 100 times lower than the highest dose at which the chemical causes no ill effects in animals. Later, the Delaney Clause of the 1960 Color Additive Amendments to the Food, Drug, and Cosmetic Act prohibited approval of any product shown to have a cancer-causing effect, no matter how small.

New, highly sensitive chemical methods for detecting minuscule quantities of cancer-causing agents — in parts per billion or parts per trillion — have complicated decision-making about safety and placed new pressures on regulatory agencies. Also, highly sensitive methods of measuring toxic changes in animals have further complicated the interpretation of long-term study results. Scientists can now detect multiple subtle biochemical and physiological changes that had previously gone unobserved. However, the health significance to humans of these changes is often unclear, creating a regulatory dilemma.

How accurately can results from animal studies — the current standard for evaluating toxicity — be applied to humans? This question has perplexed scientists for a long time.

At the turn of the century, Harvey Wiley, father of the Food and Drugs Act of 1906, conducted food additive experiments with human volunteers. Then, as now, scientists were not certain how conclusively results of animal studies could be extrapolated to humans. Wiley's volunteers, dubbed the "poison squad," consumed graduated doses of suspect chemicals, such as borax, sodium benzoate, formaldehyde, and salicylic acid. Wiley's methods and conclusions were controversial, however — disputed both by the affected industries because of possible economic repercussions and among scientists who disagreed with his studies.

Testifying before the House Subcommittee on Interstate and Foreign Commerce in 1906, Wiley had the following exchange with Congressman James D. Mann concerning the use of borax as a preservative:

Mr. Mann: Does your report show that in your opinion the use of borax has a deleterious effect upon the organs of the body?

Dr. Wiley: Of course, you understand, Mr. Mann, the tests that we have made are not the same as those made upon animals fed for pharmacological experiments because after a given time the animals are killed and their organs are examined, and the changes in the cells are studied by the microscope. We were precluded from doing that.

Mr. Mann: Is that your conclusion?

Dr. Wiley: My conclusion is that the cells must have been injured, but I had no demonstration of it, because I would not kill the young men and examine the kidneys.

Today, nearly a century later, scientists are still trying to refine methods of assessing risk to humans without endangering human life.

Adding to the confusion is frequent disagreement among experts. In his book News and Numbers, medical reporter Victor Cohn quotes Tim Hammonds of the Food Marketing Institute: "The public has become used to conflicting opinions."

On the Other Hand

In EPA's publication "Explaining Environmental Risk," Peter Sandman, Ph.D., director of Rutgers University's Environmental Communications Research Program, points to another source of frustration — the qualifications, conditions and limitations that seem always to accompany experts' statements. He explains that everyone outside his or her own field prefers simplicity, precision and certainty to complexity, approximation and tentativeness. Sandman tells about Senator Edmund Muskie's complaint about experts who kept qualifying their testimony with the phrase, "on the other hand ...". "Find me an expert with one hand," Muskie said.

"The dichotomization of risk," says Sandman, "distorts the reality that nothing is absolutely safe or absolutely dangerous, and polarizes more-or-less' disagreements into 'yes-or-no' conflicts."

The complexity of assessing and managing risk can be illustrated by last year's Alar scare. Alar is a growth-regulating chemical that was used on apples. The environmental group Natural Resources Defense Council charged that children exposed to Alar were at increased risk for cancer. After much media attention, the chemical was pulled from the market. Its manufacturer stopped selling it, and the Environmental Protection Agency proposed to phase out all allowable residue levels.

Yet, according to Bruce Ames, chairman of biochemistry and director of the Department of Environmental Health Sciences at the University of California at Berkeley, the human cancer risk from Alar is about the same as that from tap water (which contains the carcinogen chloroform) and about 30 times lower than from peanut butter (which can contain aflatoxin, a natural carcinogen).

About the Author

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FDA is A United States government body that oversees medical devices, including contact lenses, intraocular lenses, excimer lasers and eyedrops. In the US, these products must be approved by the FDA before they can be marketed.