Let's talk about the adulteration of turmeric using a neurotoxic lead chromate based dye. This is a product enhancing; adding a dye makes the product more attractive.
Turmeric is like ginger in the form of a yellow root called rhizome. This rhizome is collected and sun-dried and then ground to make a powder and used as a spice in agribusiness. Consumers and buyers of this product expect turmeric to be yellow when purchased and to color dishes in yellow.
A team from Stanford University is publishing a fascinating study on the adulteration of turmeric and more specifically how (and why) this spice is contaminated with a lead chromate based dye. The publication is in open access and accessible to all. Here are some points if you do not have time to read everything.
The team found that to make turmeric yellow, producers in Bangladesh used a lead chromate dye. They detected lead levels 500 times higher than the limit allowed in the country, and 2 to 10 times higher than the levels reported in other studies. Lead has a long-term neurotoxic effect on humans. According to the researchers, it is possible that this adulterated spice is found in exported products (Canada is one of the countries importing turmeric from Bangladesh).
This study also presents itself as a whistleblower because neither consumers nor regulators were aware of the existence of this adulteration. In addition, people who use this dye were not aware of the health risk. In fact, lead chromate dyes have been banned in foods since the beginning of the 20th century in developed countries.
Another important point is that climate plays an indirect role in this adulteration. Indeed, in case of flooding, the rhizomes can not be dried and will not have a beautiful natural yellow color. This defect will push producers to improve their products using dye.
We recommend reading this article and especially testimonials from people in Banglasdesh who are the actors of this practice.