Test each lot for lead and chromium at an accredited lab, using ICP-MS or atomic absorption. If both are raised together, lead chromate is the likely cause, and the lot should be rejected.
You cannot reliably spot lead chromate by eye, by smell or with a glass of water. A bright colour is a reason to test, not proof either way.
What lead chromate is and why it is used
Lead chromate is a bright yellow industrial pigment once used in paints. It is toxic, and lead exposure is especially harmful to children. It has no place in food.
It has been added to turmeric to make dull or low-grade fingers look bright yellow and sell for more. Researchers have documented the practice in parts of South Asia, and it has been linked to high blood lead levels. Turmeric products with high lead have also been recalled in the US and other markets.
Where the risk sits
- Coated or coloured whole fingers, where pigment is applied to the surface during polishing.
- Turmeric powder ground from coated fingers.
- Lots with unusually bright colour for their origin or price.
- Product bought through several traders, where the source is unclear.
The tests to ask for
Ask for the lab tests below on every lot. Handheld XRF analysers have been used by researchers for screening, and some buyers use them at warehouses. They are a useful first check, but confirm any result with a lab test before you act on it.
- Lead by ICP-MS or AAS, reported in mg/kg, on the actual lot.
- Chromium by the same method. Raised chromium together with raised lead is the signature of lead chromate.
- Other heavy metals such as arsenic, cadmium and mercury, which many buyers include in one panel.
- Curcumin by HPLC, so you can see whether the colour comes from the turmeric itself.
Limits and contract terms
The EU, the UK and the US apply limits or action levels for lead in spices, and these have been tightened over time. Check the current figure with the EU contaminants regulation, your national food authority or the FDA before you set your own limit.
For the polishing and coating step itself, see polished versus unpolished turmeric.
- Write "no added colour, coating or pigment" into the spec.
- Set a maximum for lead and require a test on every lot before shipment.
- Ask for the original lab report, and check that it is genuine. See how to know a lab report is genuine.
- Keep a sealed retained sample in case your own test disagrees.
How we help
We draw sealed samples from your turmeric lot and send them to an NABL-accredited lab for lead, chromium and other metals, then share the original report before you release the balance. To build a heavy metals check into your turmeric orders, ask for a free sourcing review.