A group of sulfur-based compounds is known as sulfites, and they can occur naturally in beer and wine as a result of yeast metabolism during fermentation. Sometimes, they are added to foods to make them better and attractive, and also as a preservative. They are present in a number of food items like baked goods, molasses, soup mixes, dried fruits, canned vegetables, pickled foods, juices, guacamole, etc. People diagnosed with the deficiency of enzymes that are necessary to break down sulfites in their body and those diagnosed with asthma are sensitive to sulfites. They may exhibit symptoms of a severe asthma attack or symptoms of a severe allergic reaction like an outbreak of hives. A label stating "sulfites 10 parts per million (ppm) or above" is compulsory in the U.S. A wine bottle sold in the U.S. with a label "contains sulfites" may not have such a label in other countries. Sulfites help increase the shelf life of wines, especially white wines. Addition of sulfur salts, sulfur dioxide solutions, or SO₂ gas to wines at various stages during the manufacturing process helps them to stabilize. It makes them less susceptible to oxidation. It, thus, helps prevent the development of foul odor and keeps them fresh. If SO₂ is not added, then the wine bottle needs to be stored carefully as per norms. As there is no guarantee that the consumer will store the bottle in a correct way, wine makers prefer to add SO₂ to increase its shelf life. Various brands are known for their delicate and true flavors of wines. Taking into consideration the increasing demand, more and more varieties of sulfite-free wines are being produced by the popular brands. Foods like Parmigiana, fresh and frozen shrimp, potato chips, apple cider, ocean whitefish, eggs, etc., naturally contain more sulfites than wines, and no one has ever reported about headache after eating these foods. Only those who are allergic to sulfites need to take care before incorporating such drinks and foods in their diet. Modern researches and technology have helped to develop better viticultural practices. With better quality grapes (avoiding breakage, bacteria attacks, and rotting), improved winery hygiene, and easily available information about the role played by SO₂ during winemaking, more and more manufacturers are producing wines without adding sulfites.