Sulfites Enhance Flavor and Keep Foods Fresh

The bread aisle of an Iowa grocery store.
Katrina Wittkamp / Digital Vision / Getty Images

Most of the packaged foods we eat need some type of food additives to keep the foods from spoiling or to improve the flavor or appearance. Sulfites are sulfur-based food additives that enhance flavor and preserve freshness. 

You'll see them on listed on the food label as:

  • Sulfites
  • Sulfur dioxide
  • Potassium metabisulfite
  • Potassium bisulfate
  • Sodium bisulfate
  • Sodium metabisulfite
  • Sodium sulfite

Sulfites are useful as food preservatives because they slow down bacterial growth on foods.

They also improve the quality and texture of bread dough, and prevent oxidation, or browning, of sliced vegetables and fruit. Sulfites also help keep black spots from developing on shrimp and lobster.

Sulfite Sensitivity Can Be Serious

Sulfites aren't a problem for most people. However, the United States Food and Drug Administration estimates about one percent of the American population are sensitive to sulfites. The FDA also estimates five percent of people who have asthma are allergic to sulfites.

Sulfite sensitivities may start at any time in a person's life, and reactions can be mild, such as a rash or hives, or severe enough to trigger an asthma attack. There are no treatments to block sulfite allergies, and severe reactions may require the use of epinephrine, allergy medications or asthma inhalers to reduce the symptoms.

Because sulfites can be life-threatening for those people who have sulfite sensitivity, the FDA banned their use on foods that are typically eaten raw.

They are often used in processed foods and must be noted on the food label.

Avoiding Sulfites

Sulfites are found in wine, bottled lemon or lime juice, dried apricots, molasses, grape juice and sauerkraut. Processed foods like pre-made gravies and sauces, canned vegetables, condiments, frozen shrimp, dehydrated potatoes, pickled foods, potato chips, jams and trail mix may also have them.

Sulfites also occur naturally in some foods, such as beer, wine, fruit and vegetable juices. Fresh fruits and vegetables that are meant to be eaten raw are not allowed to contain any sulfites.

Experts are not yet sure how much sulfite is enough to cause a reaction, or even what mechanisms cause the reactions to occur. The reactions and allergy symptoms may start after eating foods that contain sulfites or possible from breathing any fumes that emanate from those foods.

If you think you may have a sulfite sensitivity, please see your health care provider. He or she can help determine if you need to avoid sulfites.


University of Nebraska - Lincoln Food Allergy Research and Resource Program. "Sulfites - USA."  Accessed March 20, 2016.

United States Food and Dug Administration. "CFR - Code of Federal Regulations Title 21." Accessed March 20, 2016.

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