Sulfur dioxide was used by Romans, Ancient Greeks and Egyptian as a preservative for wine and it is used in wine making also today to prevent enzymic browning in the grape must and to inhibit the growth of lactic acid or acetic acid. Sulfur dioxide stabilizes the wine colour, works as an antimicrobial agent and antioxidant, and traps undesirable acetaldehyde. Food industry has many uses for sulfur dioxide since it prevents food spoilage and it is a powerful bleaching agent, it improves and modifies the dough in baked goods and it stabilizes vitamins. Sulfur dioxide is used in malting process in beer-making and seasonally available soft fruit is stored with added sulfur dioxide to permit the jam manufacture to proceed all the year round.
Grapes used for consumption as fruits are often fumigated with sulfur dioxide to inhibit fungus Botrytis cinerea which causes deterioration.
Sulfur dioxide destroys vitamin B1, Thiamine when it dissolves, and bleaching flours will reduce its E-vitamin content.
One reason when problems with sulfur dioxide and other sulfites arise is when a person is not able to produce enough sulfite oxidase enzyme. Having certain genetic mutations, which are expressing like SUOX, CBS etc. makes you more prone to reactions towards sulfites, and not only, you might also react to foods high in sulfur.
The irritant effects of sulfur dioxide gases may precipitate asthmatic attacks in asthma sufferers and asthma related symptoms are often the first symptoms people will notice when eating or drinking foods high in sulfur dioxide, or even when being close of environmental sulfur dioxide.
Food products where might be added sulfur dioxide, or sulfur dioxide is used in some parts of the production/manufacturing:
(Many food products can be produced also without the added sulfur dioxide so always check the labels. Organic fresh foods/food products are often the safest, but those might also contain some sulfur by products)
- White – and Red wine vinegars
- Jams made of fruits and berries stored in sulfur dioxide
- Fruit/Berry juices, specially Lemon concentrate
- Fruit/Berry syrups
- Maraschino cherries (bleached)
- Dried, crystallized or glaced fruits
- Dried, frozen or tinned vegetables
- Dried, frozen or tinned mushrooms
- Sausage meats (even though it should be avoided since SO2 destroys B1 which is present in meats)
- Any processed food which has a long shelf life: soups, snacks etc.
- Desiccated coconut flakes ( many organic coconut products are safe to use) (add brand names)
- Powdered garlic, other spices
- Soft drinks