The scientific world refers to sodium bisulfite, also known as sodium hydrogen sulfite, with the chemical formula NaHSO3. Food manufacturers refer to sodium bisulfite as E222, the number designation assigned within the European Union food additive classification system. This chemical compound is produced by mixing sulfur dioxide and sodium carbonate. Although classified and used as a food additive, the safety of sodium bisulfite remains a topic of concern.
Food and Drug Administration
The U.S. Food and Drug Administration recognizes sodium bisulfite as a food additive classified as generally recognized as safe, which the agency signifies with the initialism GRAS. The FDA does set limitations on the use of sodium bisulfite. It cannot be used in meat or in foods recognized as sources of vitamin B-1 because the sulfite destroys vitamin B-1. Common food sources of vitamin B-1, also called thiamine, include whole-grain foods, beans, nuts and lean meats. In addition the FDA prohibits the use of sodium bisulfite in fresh fruits and vegetables sold and intended to be served raw.
Wine
Winemakers use sodium bisulfite to preserve the flavor of the wine and prevent oxidation -- a reaction that occurs in the presence of oxygen. Although many commercial winemakers use a similar chemical, known as sodium metabisulfite, many home winemakers still use sodium bisulfite. The sodium bisulfite releases sulfur dioxide gas in the presence of water. The sulfur dioxide kills bacteria, yeast and fungi in the wine. After ensuring that your grape juice contains no unwanted little bugs, add yeast and allow the juice to ferment into wine. You may add more sodium bisulfite to the wine during the bottling process to prevent the growth of bacteria that can turn your wine to vinegar.
Sulfites in Wine
Many people complain that drinking wine gives them a headache or makes them feel flushed. People who suffer from asthma say that drinking wine triggers an asthma attack and they theorize that the sulfites in the wine cause the reaction. Research published in "Thorax: An International Journal of Respiratory Medicine" states that only a small number of wine-sensitive asthmatic patients responded to the sulfites in wine in the laboratory setting. The level of sulfites in the wine makes a difference but the average sulfite content of wines, 80 mg/liter, falls well below the level of 300 mg/liter that triggered a reaction in patients.
Dangers
Sodium bisulfite prevents oxidation of food, which means that it prevents browning and the deterioration of nutrients like vitamin C. This function makes sodium bisulfite desirable to use on fresh vegetables and fruits on a salad bar, keeping them looking fresh all day. Unfortunately, using too much can trigger a reaction in some people. The Food and Drug Administration banned sodium bisulfite use on fresh fruits and vegetables after investigating over 500 reports of allergic reactions that included 13 deaths, as reported by the Food Marketing Institute. So although for most people sodium bisulfite is safe, when consumed in large amounts it can cause adverse symptoms including hives, nausea and difficulty breathing if you are sensitive to sulfites.
References
- U.S. Food and Drug Administration: Sodium Bisulfite
- "Thorax: An International Journal of Respiratory Medicine"; Role of Sulfite Additives in Wine Induce Asthma; Vally, H. and Thompson, P.; October 2001
- Food Marketing Institute: Sulfites
- British Columbia Winemakers Association: The Use of SO2 in Winemaking; 2001
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