Sodium pyrosulfite or disodium are other names for this  sodium salt of sulfurous acid. Chemical formula is: Na2S2O5.

This sulfite is used in similar ways than the other ones in food processing and manufacturing. It is common ingredient used in bakeries, like other forms of sulfites, it is used as a dough conditioner to enhance the rise and preserve freshness of bread and other baked goods.

Wine and beer industry uses it as a sterilizer for equipments and as an antioxidant in the process of brewing beer or fermenting wine. It is also available in wine-making stores for those making wine at home. It will kill any alcohol-resistant mold that is on the fruit.

Sodium metabisulfites are used in cosmetic industry to act as disinfectant and as preservative.

Sodium metabisulfites have mostly the same industrial use as sodium bisulfites. In small water treatment plants sodium metabisulfite is used to remove chlorine from the waste-water before it is discharged back into the lakes and rivers.

In textile industry sodium metabisulfite is used as dechlorination agent and cotton boiling-off agent for bleached cotton. (sarongs).

Photography industry uses it as a substitute for sodium bisulfite.

Sodium metabisulfites are used in manufacturing of acrylic sheets.

Pharmaceutical industries use sodium metabisulfite as an antioxidant and preservative in many types of  medicines and it is also used as a reducing agent in pharmaceuticals.

In chemical industries it is used as a common reducing agent, but also as a bleaching agent in wood/paper pulp and textile industry.

Sodium metabisulfites are used also in landscape gardening as a tree stump remover, it disintegrates the lignin in the tree stumps, making them easier to remove.

Often the symptoms from all types of sulfites and sulfur dioxide are similar, but those can vary from person to person and certain persons are so sensitive that they can identify different symptoms  they get from different sulfites. Reactions varies also depending how the sulfites are entered in the body, Possible ways are:

• Ingesting foods and drinks and medicines
• Inhaling: gases from ‘nature’ like volcanic gases, fire works,  food smells, cooking smells, drink smells: specially from alcoholic bevarages and vinegars, medicines: asthma puffers
• Injectable medicines: EPIPEN etc.
• Intravenous medicines, contrast dyes and drips
• Skin contacts: Medical lotions and creams, rain water containing high amounts of sulfuric acid, clothes, shoes etc.
• Mucous membranes: eye drops, asthma puffers, nasal sprays, vaginal creams/douches, rectal suppositories/creams, various sulfuric acid gases from environmental sources

Foods with possible sodium metabisulfite:

• Pickled onions/cabbages
• Ready made mashed potatoes
• Quick-frozen chips/potatoes
• Quick-frozen shrimps, lobsters and other shellfish
• Sauces
• Puddings/custards
• Gelatin
• Dried fruits and nuts
• Wine
• Beer
• Cider
• Champagne
• Malt vinegar
• Maple syrup
• Baked goods like bread, pie crust, pizza crust, biscuits, cookies, shelf-stable tortilla wraps
• Potato chips
• Raisins
• Dried apples
• Fruit concentrates
• Corn syrup
• Sauerkraut

In medicines and in pharmaceutical uses;

• Injectable medicines: EPIPEN: adrenaline, some antibiotics, corticosteroids, local anaesthetics/dental anaesthetics etc.
• Intravenous medicines, contrast dyes, IV- drips
• Eye drops, vaginal creams/douches, rectal suppositories/creams
• Medical lotions and creams
• Cough syrups
• Nebulized bronchodilators = asthma puffers
• As as reducing agent in pharmaceuticals

Cosmetics and personal care products:

• Hair care products: Hair bleaches, colours, dyes, tints
• Bath and skin care products
• Face- and body-tanners
• Body- and baby powders with corn starch
• Creams and lotions

Non food uses of sodium metabisulfite, mostly same as sodium bisulfite:

• Leather industry
• Water treatments/Water pipes
• Textile industry
• Photography industry
• Rubber industry
• Acrylic sheets manufacturing
• Chemical industry

Miscellaneous:

• Garden stuff
• Landscape gardening

If you remember the brand name of a medicine you have reacted, please let me know what it was so I can add it to the list: Medicines which contain sulfites. (work on progress-and collecting data)