Sulfites as Food Additives - What AreSulfites, Where AreThey Used and Are Sulfites Safe?

Safety of Sulfites in Foods

This page will help you understand what sulfites in foods are, why and how they are used, and safety issues about their consumption. Sulfites added to baked goods, condiments, snack foods and other products are safe for most people. A small segment of the population, however, has been found to develop hives, nausea, diarrhea, shortness of breath or even fatal shock after consuming sulfites. For that reason, in 1986 FDA banned the use of sulfites on fresh fruits and vegetables (such as salad bars) intended to be sold or served raw to consumers. Sulfites added as a preservative in all other packaged and processed foods must be listed on the product label.

What are Sulfites and Why are They added to Foods?

Sulfites are used as a food preservative or enhancer. They typically used in the following forms:

  • Potassium bisulfite or potassium metabisulfite
  • Sodium bisulfite, sodium metabisulfite or sodium sulfite
  • Sulfur dioxide, which is not a sulfite, but a closely related chemical oxide

To Which Foods are They Most Commonly Added?

Wine:

(Especially white wines) Sulfites occur naturally in all wines to some extent, but sulfites are commonly added to stop fermentation at a desired point, and may also be added to wine as preservatives to prevent spoilage and oxidation at several stages of the winemaking. Sulfur dioxide (SO2, sulfur with two atoms of oxygen) protects wine from not only oxidation, but also from bacteria. Without sulfites, grape juice would quickly turn to vinegar.

Organic wines are not necessarily sulfite-free, but generally have the lowest amount because no additional sulfites are added, as with most wines. In general, white wines contain more sulfites than red wines, and sweeter wines contain more sulfites than dryer ones. In the United States, wines bottled after mid-1987 must have a label stating that they contain sulfites if they contain more than 10 parts per million.In the European Union an equivalent regulation came into force in November 2005. In 2012, a new regulation for organic wines came into force.

Dried Fruits

Sulfites are often used as preservatives in dried fruits, preserved radish, and dried potato products.In 1986, the Food and Drug Administration in the United States banned the addition of sulfites to all fresh fruit and vegetables that are eaten raw.

Shrimp

Shrimp are sometimes treated with sulfites on fishing vessels, but the chemical may not appear on the label.

Concentrations of Sulfites Used

Sulfite levels in foods are conventionally expressed as sulfur dioxide, ranging from zero to approximately 3,000 ppm on a dry weight basis. Light-colored dehydrated fruits such as apples, apricots, bleached raisins, pears, and peaches contain the greatest amount of sulfite. Dehydrated vegetables and prepared soup mixes range from a few hundred to 2000 ppm (instant potatoes average about 400 ppm). A range for wines is about 100 to 400 ppm, with beer containing 2 to 8 ppm. Some loss of sulfite occurs during food storage, either through oxidation by air to sulfate or through volatilization or evaporation. Even larger losses occur during cooking.

Sulfite Consumption

It is hard to estimate the daily intake of sulfite in the human diet due to lack of reliable information on diets and the wide variation in individual food consumption patterns. The most commonly used figure for daily intake from foods and non-alcoholic beverages in the United States is approximately 2 mg of sulfite per person per day. An additional 5 mg of sulfite per day can be added for wine and beer consumption. The Acceptable Daily Intake (ADI) of sulfites for adults is 0.70 mg per kilogram of body weight, equivalent to 50 mg of sulfite per day for a 70 kg (155 lb) person.

Sulfites ares used typically in the following foods:  

  • baked goods
  • beer
  • canned vegetables
  • condiments
  • dairy products
  • dehydrated vegetables
  • dehydrated potatoes
  • dried fruits
  • filled crackers
  • frozen potatoes
  • frozen shrimp/lobster
  • fruit juices
  • gelatin
  • grain products
  • molasses
  • nut products
  • plant protein isolates
  • processed seafood
  • soup mixes
  • sweet sauces
  • tea
  • vegetable juice
  • vinegar
  • wine

The following suggestions are helpful for sulfite-sensitive people:

  • Read food labels and choose foods that do not contain sulfites.
  • Be aware that foods served in restaurants, especially potato products and some canned foods, could contain sulfites. For example, avoid bottled lemon juice because it can be a source of sulfites. Freshly squeezed lemons do not contain sulfites.

References:

  • FASEB. 1985. The reexamination of the GRAS status of sulfiting agents. Select committee on GRAS substances. Life Sciences Research Office, Federation of American Societies for Experimental Biology. Prepared under FDA contract 223-83-2020, Jan 28.
  • FDA. 1986. Sulfiting Agents: Revocation of GRAS status for use on fruits and vegetables intended to be served or sold raw to consumers. Food and Drug Admin., Fed. Reg. 51:25021- 25026.
  • FDA. 1987. Sulfiting agents: Proposal to revoke GRAS status for use on "fresh" potatoes served or sold unpackaged and unlabeled to consumers. Food and Drug Admin., Fed. Reg. 52:46968-46978.