Turmeric powder in Accra markets contain chalk, harmful yellow azo dye— KNUST study reveals

A study conducted by researchers from the Kwame Nkrumah University of Science and Technology (KNUST) has revealed alarming findings regarding the turmeric powder sold in Greater Accra markets.

The study discovered that some turmeric products are adulterated with chalk and Metanil yellow, an unapproved and potentially harmful food colorant.

The research team, led by Associate Professor Christopher Larbie from the Biochemistry and Biotechnology Department, sampled turmeric from 10 markets, including Agbogboloshie and Malata, and found food adulterants in all the samples tested.

The study published in the European Journal of Nutrition & Food Safety sampled twenty turmeric powder products.

Metanil yellow, an azo dye not approved for food use in Ghana, was present in every sample, while chalk was detected in two of them.

The adulteration of turmeric, commonly used in Ghana for cooking and medicinal purposes, poses serious health risks.

Long-term exposure to these contaminants could lead to severe health issues, including liver cancer, cardiovascular disorders, kidney diseases, and peptic ulcers.

“What we gathered was that they add the chalk to increase the quantity of the turmeric and also enhance the yellow colouration of the vegetable,” Professor Larbie revealed.

Freshly acquired Turmeric powders are usually rich in Vitamins B complexes and C which aid in metabolism especially in Carbohydrate digestion.

The study found significantly decreasing levels of these nutrients and the pure compound, Curcumin (about 72% reduction) in the collected samples.

“The Vitamins B1 and B2 had decreased about 90% and 92% respectively. Vitamin C was zero. When you buy such products, you are not getting the actual nutrients you need for disease prevention and healing,” he said.

Professor Larbie attributes the vitamin reductions to their long exposure to the open air which alters their chemical nature as they are heat-labile or sensitive. Although the study couldn’t conclude on the quantity of the contaminants in the samples, the researchers explain that the health implications should be a concern for public education.

"The human body is highly sensitive to food adulteration with accompanying side effects including diarrhoea, dysentery and vomiting.

"The complications of the long-term adverse effects of adulterated foods are associated with diseased conditions which may include cancer of the liver, cardiovascular disorders, peptic ulcers, kidney related problems, etc.

“Metanil yellow is toxic on the liver, brain, and reproductive systems. It has negative effects on some of the brain hormones. Metanil yellow hasn’t been approved as a food colour in Ghana,” Prof. Larbie said.

While the scientists advise regular and periodic food surveillance, the public can detect an adulterated turmeric powder by dissolving it in water – if the turmeric powder takes long to dissolve indicating the presence of chalk.

However, the powder could contain metanil yellow if it stains the tongue with a yellow hue.