E924b - Calcium bromate
What it is and how it is used
Calcium bromate is the calcium counterpart of potassium bromate, and it does the same job by the same chemistry: it oxidises the sulphur bonds in gluten so dough becomes stronger and more elastic, giving a taller loaf with a finer crumb.
Swapping potassium for calcium changes the handling properties of the powder, not the toxicological question, because it is the bromate ion that carries the concern.
Foods commonly containing it
None in Great Britain. As with potassium bromate, bromate flour treatment ended in the UK in 1990.
Safety summary
Calcium bromate does not appear in the FSA Register of Food Additive Authorisations and is not permitted for food use in Great Britain. Bromate flour treatment agents were prohibited in the UK from 1 April 1990.
The concern is the bromate ion. IARC classified potassium bromate as Group 2B, possibly carcinogenic to humans, in Monographs Volume 73 (1999), on sufficient evidence of carcinogenicity in animals — renal tubular and thyroid tumours in rats — and inadequate evidence in humans. We have not found a separate IARC evaluation for the calcium salt, and we are not going to imply one exists; the honest statement is that the anion is common to both and neither is permitted here.
Great Britain permits ascorbic acid (E 300) and L-cysteine (E 920) as flour treatment agents.
Known concerns
Shares the bromate anion with potassium bromate, which IARC classifies as Group 2B, possibly carcinogenic to humans. No separate IARC evaluation of the calcium salt was found.