What Are Sulfites?
Sulfites (also spelled 'sulphites') are a family of sulfur-based chemical compounds used as food preservatives and antioxidants. In the EU and US, they are classified as food allergens requiring mandatory declaration on labels. The sulfite family includes:
• E220 — Sulfur dioxide (SO2)
• E221 — Sodium sulfite
• E222 — Sodium bisulfite
• E223 — Sodium metabisulfite
• E224 — Potassium metabisulfite
• E226 — Calcium sulfite
• E227 — Calcium bisulfite
• E228 — Potassium bisulfite
Sulfur dioxide is also produced naturally during wine fermentation, so even 'no added sulfites' wines may contain some sulfites.
Who Is Sensitive to Sulfites?
The FDA estimates approximately 1% of the general population is sulfite-sensitive. The rate is higher among people with asthma — studies suggest 5-10% of asthmatics are sulfite-sensitive.
Reactions range from mild (skin flushing, hives, runny nose) to severe (bronchoconstriction, anaphylaxis). Reactions typically occur within 15-30 minutes of ingestion.
Sulfite sensitivity is not a true IgE-mediated allergy in most cases — it's more of a hypersensitivity reaction. However, it can be just as severe as traditional allergies.
Foods High in Sulfites
High sulfite content (>50 ppm):
• Wine (especially white wine and red wine)
• Dried fruits (apricots, raisins, prunes)
• Grape juice
• Pickled products
Moderate sulfite content (10-50 ppm):
• Processed meats
• Canned vegetables
• Some bottled fruit juices
• Vinegar
Lower sulfite content:
• Fresh fruits and vegetables (trace amounts naturally)
• Beer
• Some condiments
Note: The FDA banned sulfite use on raw fruits and vegetables served in restaurants in 1986 after several deaths were linked to sulfite-treated salad bar items.
Label Reading for Sulfites
In the EU: Sulfites must be declared on labels when present above 10 mg/kg or 10 mg/L. Look for 'sulphites', 'sulfur dioxide', or E-numbers E220-E228. Wines must declare 'contains sulphites.'
In the US: The FDA requires declaration of sulfites when present above 10 ppm. Look for 'sulfites', 'sulfur dioxide', 'sodium bisulfite', 'potassium bisulfite', 'sodium metabisulfite', or 'potassium metabisulfite' in the ingredient list.
For sulfite-sensitive individuals: When in doubt about a product, contact the manufacturer. Fermented products and dried fruits are the highest-risk categories.