sulfite and bisulfite, the negatively charged ions liberated when sulfurous acid dissociates, as shown below:
The analytical method usually used for the measurement of sulfite determines all of the various forms which are active in terms of smell, effect on yeast and bacteria, and potential danger to asthmatics (see sulfur dioxide). The term sulfites, or sulphites, is therefore used on wine labels (as in ‘Contains sulfites/sulphites’) as an inclusive term for free sulfur dioxide, sulfurous acid (hydrated sulfur dioxide), bisulfite ion, sulfite ion, and some forms of complexed sulfite. See labelling information and allergies and intolerances.
