Food Preservatives : BHA, Sulfites

by Food and Drug Administration (FDA)

(Page 2 of 3)

BHA

BHA and the related compound butylated hydroxytoluene (BHT) have been used for years, mostly in foods that are high in fats and oils. They slow the development of off-flavors, odors, and color changes caused by oxidation. When the food additives amendment was enacted, BHA and BHT were listed as common preservatives considered generally recognized as safe (GRAS). GRAS regulations limit BHA and BHT to 0.02 percent or 200 parts per million (ppm) of the fat or oil content of the food product.

Lawrence Lin, Ph.D., of FDA's Center for Food Safety and Applied Nutrition, explains, "The 0.02 percent allowed relates only to the product's fat content. For example, if a product weighs 100 grams and one of those grams is fat, the quantity of BHA in the product cannot exceed 0.02 percent of that one gram of fat."

BHA is also used as a preservative for dry foods, such as cereals. But because such foods contain so little fat, the amount of BHA allowed cannot be measured against the percentage of fat, explains Lin. Therefore, as manufacturers petitioned FDA for approvals for this use, the agency set limits for each type of food. On cereals, for example, FDA limited BHA to 50 ppm of the total product.

In 1978, under contract with FDA, the Life Sciences Research Office of the Federation of American Societies for Experimental Biology (FASEB) examined the health aspects of BHA as part of FDA's comprehensive review of GRAS safety assessments. FASEB concluded that although BHA was safe at permitted levels, additional studies were needed.

Since that evaluation, other studies suggested that at very high levels in the diets of laboratory animals, BHA could cause tumors in the forestomach of rats, mice and hamsters, and liver tumors in fish. Many experts examined the data and concluded the tests did not establish that such problems could exist in humans, mostly because humans do not have forestomachs. Other studies showed that BHA was protective, inhibiting the effect of some chemical carcinogens, depending on the conditions of the tests.

Studies on BHA were reviewed by scientists from the United Kingdom, Canada, Japan, and the United States. Their findings were published in 1983 in the Report of the Working Group on the Toxicology and Metabolism of Antioxidants and reviewed in the 1990 Annual Review of Pharmacology and Toxicology. The 1983 report stated that data from a Japanese study showed a high incidence of cancerous tumors and papillomas (benign tumors of the skin or mucous membranes) of the forestomach of treated rats and that the effect was dose-related. The report also mentioned the possible existence of a no-effect level, based on dose response, and noted that the level which produced cancer in this study was many thousands of times higher than the level to which humans are exposed.

In November 1990, Glenn Scott, M.D., a physician then living in New York who has since moved to Cincinnati, filed a petition with FDA, asking the agency to prohibit the use of BHA in food. Scott cited animal studies to support his request. Before acting on Scott's petition, however, FDA asked FASEB to reexamine the scientific data on BHA. By March 1994, FASEB is scheduled to provide FDA with a report on the most current scientific information bearing on the relationship of BHA ingestion to cancer in animals.

Sulfites

Sulfites are used primarily as antioxidants to prevent or reduce discoloration of light-colored fruits and vegetables, such as dried apples and dehydrated potatoes. They are also used in wine-making because they inhibit bacterial growth but do not interfere with the desired development of yeast.

Sulfites are also used in other ways, such as for bleaching food starches and as preventives against rust and scale in boiler water used in making steam that will come in contact with food. Some sulfites are used in the production of cellophane for food packaging.

FDA prohibits the use of sulfites in foods that are important sources of thiamin (vitamin B1), such as enriched flour, because sulfites destroy the nutrient.

Though most people don't have a problem with sulfites, some do. FDA's sulfite specialist, consumer safety officer Joann Ziyad, Ph.D., points to a bookcase full of binders and says, "Those are the case histories of adverse reactions to sulfites that have been reported to FDA. Since 1985, when the agency started reporting on sulfites through the Adverse Reaction Monitoring System, over 1,000 adverse reactions have been recorded."

As reports of adverse reactions mounted, FDA asked FASEB to reexamine the use of sulfites. FASEB's report, released in 1985, concluded that sulfites posed no hazard to most Americans, but that they were a hazard of unpredictable severity to people who were sensitive to the substance. Based on the FASEB study, FDA estimated that more than 1 million asthmatics are sensitive or allergic to the substance.

In 1986, FDA ruled that sulfites used specifically as preservatives must be listed on the label, regardless of the amount in the finished product. Sulfites used in food processing but not serving as preservatives in the final food must be listed on the label if present at levels of 10 parts per million or higher. Regulations issued in 1990 extended these required listings to standardized foods.

About the Author

www.fda.gov
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.