A bite of cancer?

A CSE study has found residues of potassium bromate and/or iodate in many types of bread. The additives have been banned by many countries for their potentially adverse health effects


CSE test and results

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A new study by Delhi-based non-profit Centre for Science and Environment (CSE) has shown that 84 per cent of bread and bakery samples collected from the city contain residues of potassium bromate, potassium iodate or both. Potassium bromate (KBrO3) and potassium iodate (KIO3) are chemical food additives which, according to Indian food regulations, can be used by bread makers and bakeries as flour treatment agents. Potassium bromate helps achieve high rising and a uniform finish. But the safety of these additives is under a cloud.

Popularly used in many parts of the world a few decades ago, potassium bromate was allowed based on the assumption that no residue of bromate would be found in the final product. However, studies began to find detectable residues of bromate in finished products. Other studies showed that bromate was a possible carcinogen. In the 1980s and early 1990s, global scientific expert committees began reducing the allowed limit of use for bromate. Eventually, they recommended not using potassium bromate at all, a warning that was heeded in many countries. Potassium iodate is also banned in many countries as it can lead to higher intake of iodine, which can potentially affect thyroid function. But India continues to allow the use of these treatment agents, exposing people to the risk of consuming them through bread and bakery items.

To find out if potassium bromate and potassium iodate are present in different types of breads, the Pollution Monitoring Laboratory (PML) at CSE collected 38 bread and bakery samples from retail shops, bakeries and fast food outlets in Delhi during May-June 2015. The samples included popular varieties of white bread, whole wheat/atta bread, brown bread, multigrain bread, sandwich bread, pav, bun, ready-to-eat burger bread and ready-to-eat pizza bread. The tests were conducted on a UV-visible spectrophotometer using a published method. Both potassium bromate and potassium iodate oxidise the dye, producing the same colour and indicating the presence of either one or both chemicals. The results were startling.

  • Thirty two of 38 samples or more than 84 per cent of samples tested were found to contain potassium bromate and/or iodate in the range of 1.15–22.54 ppm (parts per million). Moreover, residues of potassium bromate and/or iodate were found in all product categories tested by PML (see ‘A grim report card’).
  • All samples of white bread, pav, bun and ready-to-eat pizza bread were found to contain potassium bromate and/or iodate. Nineteen of 24 samples or 79 per cent of bread and about 75 per cent of ready-to-eat burger bread also tested positive for the chemicals.
  • The highest level of potassium bromate and/or iodate was found in sandwich bread. This was followed by pav, bun and white bread. Even the average level of the residues was high in these product categories.
  • Products of Perfect Bread, Harvest Gold and Britannia were found to contain high average levels of potassium bromate and/or iodate. Harvest Gold Sandwich bread had the highest concentration of the chemicals.
  • Products of all seven popular fast food outlets selling pizza and burger tested positive for potassium bromate and/or iodate, but at levels lower than those found in bread, pav and bun.

Download the CSE Policy Brief (POTASSIUM BROMATE/IODATE IN BREAD AND BAKERY PRODUCTS) and CSE Lab Report (Potassium Bromate or Potassium Iodate in Bread). View the CSE presentation here.


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