Is Sulfur Dioxide as a Preservative Bad for You?

December 13, 2025 •

4 min read

While sulfur dioxide is widely utilized for its antimicrobial properties and ability to prevent browning in foods, its effects on human health vary depending on the individual. Health authorities consider it safe for the general population when used within regulated limits, but sensitive groups, particularly asthmatics, may experience adverse reactions.

Quick Summary

Sulfur dioxide is a common food preservative, safe for most but triggering adverse reactions in sensitive individuals, especially those with asthma or sulfite intolerance. Labels must declare its presence, and regulations control its use to ensure consumer safety.

Key Points

Generally Safe for Most: In regulated amounts, sulfur dioxide is considered safe for the general, healthy population as a food preservative.
Dangerous for Sensitive Individuals: People with asthma or sulfite sensitivity can experience adverse reactions, including severe respiratory symptoms and anaphylaxis.
Multiple Food Uses: It is used to prevent microbial growth, extend shelf life, and inhibit oxidation and browning in foods like dried fruit and wine.
Strict Labeling Laws: Regulations require manufacturers to declare the presence of sulfites on food labels when concentrations exceed 10 parts per million.
Adverse Symptoms Vary: Reactions can range from mild effects like skin rashes and abdominal pain to severe breathing difficulties.
Risk for Asthmatics: Up to 13% of people with asthma may be sensitive to sulfites, making careful consumption necessary.
Look for Alternatives: For those with sensitivity, organic products or those labeled 'no sulfites added' are safer options.

What is Sulfur Dioxide and Why is it Used in Food?

Sulfur dioxide ($SO_2$) is a colorless gas with a pungent smell, widely used in the food and beverage industry for its preservative and antioxidant properties. Its use dates back to ancient times, with Romans using it to preserve wine vessels. In modern food production, it serves several key functions:

Antimicrobial Agent: It inhibits the growth of microbes like yeasts, bacteria, and molds, extending the shelf life of products such as dried fruits, pickled vegetables, and wines.
Antioxidant: It prevents oxidation, which causes browning and discoloration in foods, helping to maintain their appearance and color. This is particularly important for dried fruits like apricots, which can darken quickly when exposed to air.
Flavor Protection: In winemaking, $SO_2$ protects the wine from spoilage and oxidation, preserving its quality and flavor.
Fumigant: Historically, and in some contexts still, $SO_2$ has been used to fumigate certain foods.

Health Effects of Sulfur Dioxide for the General Population

For the vast majority of healthy individuals, consuming food products that contain sulfur dioxide in regulated amounts is considered safe. The Joint Food and Agriculture Organization / World Health Organization Expert Committee on Food Additives (JECFA) has evaluated its safety and concluded that it is safe for food use under Good Manufacturing Practices (GMP). Your body has a natural way of processing and eliminating sulfites, converting them into harmless sulfates that are excreted.

However, it is worth noting that excessive intake of sulfite-containing products, even for non-sensitive individuals, has been flagged by food safety experts. For instance, a 2017 study found that high levels of sulfites could negatively impact gut bacteria. European food safety experts have also indicated that a high percentage of consumers who eat large amounts of sulfite-containing foods might exceed the acceptable daily intake, potentially increasing health risks.

Special Considerations for Sensitive Individuals

While most people tolerate sulfites without issue, a smaller segment of the population, particularly those with asthma, can experience adverse reactions. This sensitivity is not a true allergy but rather an intolerance that can trigger allergy-like symptoms.

Symptoms of sulfite sensitivity can include:

Wheezing, coughing, and chest tightness
Asthma attacks, sometimes severe
Skin rashes, such as urticaria (hives)
Dermatitis
Flushing and dizziness
Abdominal pain and diarrhea
Rarely, life-threatening anaphylactic reactions

The incidence of sulfite sensitivity is estimated to be less than 2% in the general population, but significantly higher—between 5% and 13%—among asthmatics. In sensitive individuals, ingested sulfites can release sulfur dioxide gas in the stomach, which can irritate the airways and trigger bronchoconstriction.

Comparison of Preservative Options


Feature	Sulfur Dioxide (SO2) / Sulfites	Alternatives (e.g., Citric Acid, Ascorbic Acid)
Effectiveness	Highly effective antimicrobial and antioxidant, especially for dried fruits and wine.	Can be less potent or effective for specific applications, like preventing browning in dried fruits.
Health Risks	Triggers allergic-type reactions in sensitive individuals, primarily asthmatics. Safe for most people in regulated amounts.	Generally considered safe, though high doses of some alternatives can have minor side effects.
Regulation	Heavily regulated, requires clear labeling on packaged foods containing over 10 ppm of sulfites.	Subject to food additive regulations but may not have the same specific labeling requirements for sensitivities.
Application	Broadly used in dried fruits, wines, and certain processed meats.	Used in many foods, beverages, and as a natural antioxidant.
Appearance	Maintains vibrant color in dried fruits like apricots.	Some alternatives may not be as effective at preventing browning, leading to color changes.

Regulatory Actions and Labeling

Recognizing the potential for adverse reactions in sensitive individuals, regulatory bodies around the world have established strict rules regarding the use and labeling of sulfites. In 1986, the U.S. Food and Drug Administration (FDA) banned the use of sulfites on fresh fruits and vegetables to be served raw to the public. For all other foods, the presence of sulfites at concentrations of 10 parts per million (ppm) or more must be declared on the product label.

When reading ingredient labels, look for terms such as:

Sulfite or Sulphite
Sulfur Dioxide ($SO_2$)
Potassium Bisulfite (E222)
Sodium Bisulfite (E222)
Potassium Metabisulfite (E224)
Sodium Metabisulfite (E223)

For those with sulfite sensitivity, avoiding foods that contain these ingredients is the primary management strategy. Organic dried fruits, for example, are typically produced without the use of sulfur dioxide.

Conclusion

For the average consumer, sulfur dioxide as a preservative is not bad for you, as its use is closely monitored and regulated by food safety authorities. However, the safety of this additive is entirely dependent on individual tolerance. For the segment of the population with asthma or specific sulfite sensitivity, the preservative can trigger a range of adverse, sometimes severe, reactions. Careful label reading is essential for sensitive individuals to avoid health complications. Given the availability of preservative-free alternatives, those with sensitivities can make informed choices to protect their health while still enjoying a wide variety of foods.

Finding Preservative-Free Options

For those who need to avoid sulfur dioxide, there are several ways to find sulfite-free products:

Read Labels Carefully: Always check the ingredient list for sulfites or their chemical names (E220-E228).
Choose Organic: Organic dried fruits are a reliable option as they do not use sulfur dioxide as a preservative.
Look for 'No Sulfites Added': This label is common on certain products like wine and indicates sulfite levels below the regulated declaration threshold.
Consult a Health Professional: If you suspect a sulfite sensitivity, a doctor or allergist can perform tests and provide guidance.
Prepare Your Own Food: For dried fruits, you can prepare your own preservative-free batches at home by baking fruit slices at low heat.

Frequently Asked Questions

Sulfur dioxide is a chemical used as a preservative and antioxidant in food processing, identified by the code E220 in Europe. It prevents microbial growth and oxidation, which in turn extends shelf life and maintains the food's appearance, particularly in dried fruits and wines.

For most healthy individuals, consuming sulfur dioxide within the regulated limits is safe. It has undergone safety assessments, and the body can process it effectively. However, some studies suggest high consumption could pose risks, including negative impacts on gut bacteria.

Common foods that contain sulfur dioxide include dried fruits (like apricots, figs, and raisins), wine, pickled vegetables, some processed meats (e.g., sausages), fruit juices, and certain jams.

Symptoms of sulfite sensitivity or intolerance can include wheezing, chest tightness, coughing, skin rashes, headaches, nausea, and abdominal pain. In rare, severe cases, it can trigger anaphylaxis.

You can avoid sulfur dioxide by carefully reading food labels and choosing organic dried fruits, which are typically preservative-free. Look for product labels that specifically state 'no sulfites added'.

A severe reaction to sulfites can cause life-threatening anaphylaxis, characterized by rapid onset of symptoms such as severe breathing difficulties, swelling of the throat, and collapse.

The U.S. FDA banned the use of sulfites on fresh fruits and vegetables in 1986 because of the health issues they caused in some individuals, particularly those with asthma.