What are Sulfites and Why are They in Food?
Sulfites are chemical compounds that act as preservatives, antioxidants, and antimicrobials to prevent spoilage and maintain the color and freshness of many food and beverage products. They are regulated food additives, but also occur naturally in some items as a byproduct of fermentation. While most people can consume them without issue, a small percentage of the population, particularly those with asthma, may experience adverse reactions such as wheezing, hives, and other allergy-like symptoms.
Dried Fruits: Among the Highest Sources
Dried fruits are one of the most concentrated sources of added sulfites. Manufacturers use sulfites to preserve color and extend shelf life. Light-colored fruits, such as dried apricots and golden raisins, typically contain higher levels to prevent browning. Sulfur dioxide is a common sulfiting agent used for this purpose.
Common sulfite-treated dried fruits:
- Apricots: Often have a high concentration to maintain their vibrant orange color.
- Golden Raisins: Treated with sulfites to keep their light hue.
- Mango and Pineapple: Dried versions often contain sulfites to prevent discoloration and spoilage.
- Prunes and Figs: While some brands are sulfite-free, it is important to check the label for preservatives.
Beverages with High Sulfite Content
Wine and Beer
All wine contains some naturally occurring sulfites due to the fermentation process. However, additional sulfites are often added to inhibit bacterial growth and prevent oxidation. The sulfite levels vary by wine type.
- Sweet wines and white wines often have the highest sulfite levels to prevent spoilage and maintain flavor, as they lack the tannins found in red wine that offer natural protection.
- Red wines generally contain lower levels of added sulfites because the natural tannins provide some protection.
- Beer and cider also contain sulfites, which can sometimes be inhaled as sulfur dioxide gas when drinking, potentially triggering symptoms in sensitive individuals.
Other Beverages
Beyond alcohol, many non-alcoholic drinks also contain sulfites.
- Bottled Lemon and Lime Juice Concentrates: Often use sulfites as a preservative.
- Soft Drinks and Fruit Juices: Some varieties, particularly fruit juice concentrates and carbonated drinks, may contain sulfites.
Processed and Preserved Foods
Sulfites are common in a wide array of processed foods to increase shelf life and maintain texture.
- Processed Potatoes: Dehydrated potatoes, frozen french fries, and instant mashed potatoes can all contain sulfites.
- Processed Meats: Deli meats, sausages, and hot dogs may use sulfites.
- Seafood: Shrimp and other crustaceans may be treated with sulfites to prevent black spots and discoloration.
- Condiments and Sauces: Pickled foods, vinegar, salad dressings, and some gravy or sauce mixes can contain sulfites.
- Baked Goods: Packaged baked goods like crackers, pie crusts, and pizza dough sometimes contain sulfites as preservatives.
Comparing Sulfite Levels: A Snapshot
| Food Category | Typical Sulfite Levels | Key Considerations |
|---|---|---|
| Dried Fruits | High | Added as a preservative to maintain color and freshness. |
| Sweet/White Wines | High | Higher levels of added sulfites than red wine due to lower tannins. |
| Processed Potatoes | Medium to High | Used to prevent browning and spoilage in instant or frozen products. |
| Processed Meats | Medium | Can be added to items like sausages and deli meats. |
| Beer and Cider | Medium | Contain both naturally occurring and added sulfites. |
| Red Wines | Medium to Low | Generally lower added sulfites due to natural tannins. |
| Fresh Produce | Low (if any) | FDA banned sulfite use on fresh fruits and vegetables. |
| Naturally Occurring | Very Low | Found in fermented foods and some vegetables like onions and cabbage. |
Identifying and Avoiding Sulfites
Reading food labels is the most critical step in managing sulfite intake. In many countries, including the U.S., sulfites must be declared on the label if they are present at levels of 10 parts per million (ppm) or more. Look for specific terms like:
- Sulfur dioxide
- Sodium sulfite
- Sodium bisulfite
- Potassium bisulfite
- Potassium metabisulfite
When dining out, especially at places with salad bars or fried potatoes, exercise caution as restaurant staff may add sulfites to maintain the fresh appearance of food. For individuals with a sensitivity, discussing ingredients with kitchen staff is recommended. Some pharmaceuticals and cosmetics may also contain sulfites, so it's wise to check labels there as well. You can find additional resources on this topic from health authorities. Learn more about sulfite sensitivity from Allergy & Anaphylaxis Australia
Conclusion
Sulfites are common food preservatives, with dried fruits, wine, beer, and processed foods being the most significant sources. While most people tolerate them well, those with sensitivities must be diligent in reading labels and questioning ingredients, especially in processed and restaurant foods. By understanding what foods contain the most sulfites and knowing how to identify them, sensitive individuals can effectively manage their diet and avoid adverse reactions. The distinction between naturally occurring sulfites and higher concentrations in processed items is key to making informed dietary choices.
