This has also prompted the Union Health Ministry to order a probe.
Most of the breads made by Indian companies are laced with chemicals such as potassium bromate or iodate that damage human health, a study conducted by the Centre for Science and Environment (CSE) has suggested.
The study, conducted by CSE's pollution monitoring laboratory, said Indian bread manufacturers use potassium bromate and potassium iodate for treating flour.
"The use of these chemicals in the bread-making sector has been banned in many countries because they are listed as hazardous for public health: one is a category 2B carcinogen and the other could trigger thyroid disorders. India does not ban the use of any of these," the CSE report said.
The CSE tested 38 commonly available branded varieties of pre-packaged breads, pav and buns, ready-to-eat burger bread and ready-to-eat pizza breads of popular fast food outlets from Delhi.
"We found 84 percent samples positive with potassium bromate or iodate. We re-confirmed the presence of chemicals in a few samples through an external third-party laboratory. We checked labels and talked to industry and scientists," CSE's Deputy Director General Chandra Bhushan said.
CSE said, "High levels of potassium bromate/iodate were found in sandwich bread, pav, bun and white bread" involving virtually all top brands. CSE has urged food regulator FSSAI to ban the use of potassium bromate and potassium iodate with immediate effect and prevent their routine exposure to Indian population.
Health impacts of these two chemicals
In 1999, the International Agency for Research on Cancer (IARC) classified potassium bromate as possibly carcinogenic (cancer causing) to humans. It was found to cause tumours of the kidney, thyroid and cancer of the abdominal lining in laboratory animals.
The European Union had banned its use in 1990. The United Kingdom, Canada, Australia, New Zealand, China, Sri Lanka, Brazil, Nigeria, Peru and Columbia have also banned the use of potassium bromate.
(With inputs from agencies)