Lead chromate, which is toxic and carcinogenic, is used to adulterate:

Food adulteration means adding cheaper, inferior or harmful substances to food, or removing valuable parts from it, so that its quality is reduced. Adulteration is done mainly to increase profits, but it can seriously harm health.

Lead chromate (PbCrO4) is a bright yellow chemical used as a pigment in paints. Some dishonest traders add it to turmeric powder and to whole turmeric roots to give them a brighter, more attractive yellow colour, and to make low-quality or old turmeric look fresh. Metanil yellow, a non-permitted dye, is also used for the same purpose.

Lead chromate is highly toxic. Lead can damage the brain and nervous system, especially in children, and can cause anaemia, kidney damage and problems with mental development. Hexavalent chromium is a known carcinogen (cancer-causing substance). Studies in South Asia have linked lead chromate in turmeric to high levels of lead in people's blood.

A simple test: dissolve a little turmeric in water. If lead chromate is present, it may leave a bright yellow colour that does not change; laboratory tests confirm it. For metanil yellow, adding a few drops of hydrochloric acid to a turmeric solution turns it pink if the dye is present.

In India, food safety is regulated by the Food Safety and Standards Authority of India (FSSAI), set up under the Food Safety and Standards Act, 2006. FSSAI has published simple home tests in its "DART" (Detect Adulteration with Rapid Test) book.

Other common adulterants include papaya seeds in black pepper, water and starch in milk, used tea leaves or iron filings in tea, brick powder in chilli powder, and argemone seeds in mustard seeds (which cause epidemic dropsy).

Why not the other options?

• ✗Black pepper is adulterated with dried papaya seeds.
• ✗Milk is adulterated with water, starch, urea and detergent.
• ✗Tea leaves are adulterated with used tea leaves, colours or iron filings.