Sulphur dioxide is a preservative commonly used in a variety of foods and beverages such as dried fruits, pickled vegetables, sausages, fruit and vegetable juices, cider, vinegar, wine, etc. . It is used to extend the shelf life of food products and prevent spoilage caused by microbes. Sulphur dioxide can inhibit the growth of microbes such as yeasts, bacteria, and molds by crossing the cell walls of microbes and disrupting their normal functioning. It can also act as an antioxidant that prevents browning associated with oxidation in foods, particularly dried fruits and vegetables. However, sulphur dioxide can induce asthma when inhaled or ingested by sensitive subjects, even in high dilution. About one in nine asthmatics gives a history of asthma worsened by drinking soft drinks containing sulphur dioxide. Exposure to sulphur dioxide may also occur during the manufacture and preparation of foods and drinks in the factory, restaurant, and home. The amount of sulphur dioxide in foods is limited by regulation in the UK, by directive in the EEC, and by recommendations to good manufacturing practice in the USA. If you are sensitive to sulphur dioxide, you should read food labels carefully every time when shopping for food and look for the names of sulphur dioxide, sulphites, and sulphite derivatives or their International Numbering System numbers (220, 221, 222, 223, 224, 225, 226, 227, and 228) on the ingredient list, and avoid all food products containing these compounds.