By Carol Ann Rinzler

The safety of any chemical approved for use as a food additive is determined by evaluating its potential as a toxin, carcinogen, or allergen, each of which is defined here.

Defining toxins

A toxin is a poison. Some chemicals, such as cyanide, are toxic (poisonous) in very small doses. Others, such as sodium ascorbate (a form of vitamin C), are nontoxic even in very large doses. All chemicals on the generally recognized as safe (GRAS) list are considered nontoxic in the amounts that are permitted in food.

By the way, both vitamin C and cyanide are natural chemicals — one beneficial, the other not so much.

Explaining carcinogens

A carcinogen is a substance that causes cancer. Some natural chemicals, such as aflatoxins (poisons produced by molds that grow on peanuts and grains), are carcinogens. Some synthetic chemicals, such as specific dyes, are also potentially carcinogenic.

In 1958, driven by a fear of potentially carcinogenic pesticide residues in food, New York Congressman James Delaney proposed, and Congress enacted into law, an amendment to the Food, Drug, and Cosmetic Act that banned from food any synthetic chemical known to cause cancer (in animals or human beings) when ingested in any amount, no matter how small. (The Delaney clause didn’t apply to natural chemicals, even those known to cause cancer.)

For a time, the only exception to the Delaney clause was saccharin, which was exempted in 1970. Although ingesting very large amounts of the artificial sweetener is known to cause bladder cancer in animals, no similar link was ever found to human cancers. Nonetheless, in 1977, Congress required all products containing saccharin to carry a warning statement: “Use of this product may be hazardous to your health. This product contains saccharin, which has been determined to cause cancer in laboratory animals.”

When the Delaney clause was introduced, ingredients such as additives were measured in parts (of the additive) per thousand parts (of the product). Today, scientists have the ability to measure an ingredient in parts per trillionths. As a result, the zero-risk standard of the Delaney clause in regard to pesticide residue in food was repealed and replaced with a standard of “reasonable risk.” The saccharin warning was lifted in 2000.

Listing allergens

Allergens are substances that trigger allergic reactions. Some foods, such as peanuts, contain natural allergens that can provoke the fatal allergic reaction known as anaphylaxis.

The best-known example of an allergenic food additive is the sulfites, a group of preservatives that

  • Keep light-colored fruits and vegetables (apples, potatoes) from browning when exposed to air
  • Prevent shellfish (shrimp and lobster) from developing black spots
  • Reduce the growth of bacteria in fermenting wine and beer
  • Bleach food starches
  • Make dough easier to handle

Sulfites are safe for most people but not for all. In fact, the FDA estimates that 1 out of every 100 people is sensitive to these chemicals; among people with asthma, the number rises to 5 out of every 100. For people sensitive to sulfites, even infinitesimally small amounts may trigger a serious allergic reaction, and asthmatics may develop breathing problems by simply inhaling fumes from sulfite-treated foods.

In 1986, the FDA tried banning sulfites from food but lost in a court case brought by food manufacturers, so two years later the agency wrote rules to protect sulfite-sensitive people.

Today, sulfites are not considered GRAS for use in

  • Meats
  • Foods that are an important source of vitamin B1 (thiamin), a nutrient sulfites destroy
  • Fruits and veggies served raw (think salad bars), or described as “fresh” (think fruit salad)

Sulfites are permitted in some foods, such as dried fruit, but the package must list sulfites if the additives account for more than ten parts sulfites to every million parts food (10 ppm). These rules, plus plenty of press information about the risks of sulfites, have led to a dramatic decrease in the number of sulfite reactions.