Tumeric powder adulteration is a public health concern

Researchers at the Kwame Nkrumah University of Science and Technology (KNUST) have found the presence of chalk and Metanil yellow, an unapproved food colorant, in some powdered Turmeric products sold on the mar­kets in Greater Accra.

A recent study by the Biochemis­try and Biotechnology Department detected food adulterants in all samples sourced from 10 markets in the metropolis.

The long-term adverse effects of the chemicals pose deleterious health risks to humans including cancer of the liver, cardiovascular disorders, peptic ulcers, and kidney diseases.

Turmeric powder is a common local spice, food preservative, and colourant used in many Ghanaian households for various culinary and medicinal purposes.

It has gained attention for its plethora of benefits including a remedy for diabetic wounds, hepatic disorders, rheumatism, and cough amongst others.

Curcumin, the major active component of turmeric, gives the root plant its prominent yellowish colouration, nutritional and medici­nal benefits.

But the zest to increase the quan­tity and colouration of the powdered product has seen vendors adulterate the local spice.

Associate Professor of Biochem­istry, Prof. Christopher Larbie, led the team of scientists to uncover the trend in the local markets in Accra including Agbogboloshie, Malata and others.

“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,” he said.

The study published in the Euro­pean Journal of Nutrition & Food Safety sampled 20 turmeric powder products from 10 market centres in the Accra metropolis.

All the samples taken from the market were found to be adulterated with metanil yellow – an azo dye – while two contained chalks.

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 per cent and 92 per cent 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.

The scientists attribute 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 their detection 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.

My Opinion

In this article, I will discuss how to detect contaminated turmeric.

Common Forms of Turmeric Adulteration

1. Adding artificial colouring agents to turmeric is a common form of adulteration. Coloring agents such as lead chromate may be added to improve the appearance of turmeric and make it appear more yellow or brighter. Coloring agents dilute the turmeric’s quality and pose a health risk, as some artificial colouring agents, such as lead chro­mate, are toxic and can cause serious health problems if consumed.

2. Adulteration can occur in turmeric by mixing it with cheaper spices to increase the product’s vol­ume and reduce costs. This practice dilutes the quality and flavor of turmeric and reduces its nutritional value. Common adulterants that may be added to turmeric include papri­ka, cornstarch, and sawdust. These mixtures may also contain contami­nants, such as mold or bacteria, that can pose a health risk to consumers.

3. Using filler materials, such as starch or other cheap powders, is another form of turmeric adultera­tion. Filler materials may be added to dilute the turmeric and increase its volume to reduce costs and increase profit margins. This practice reduces the quality and nutritional value of the turmeric and can also pose a health risk if the filler materials are not food-grade or are contam­inated with harmful substances. Lead may be added to turmeric as a colouring agent or filler material. Lead is a toxic substance that can cause serious health problems, including damage to the brain and nervous system if consumed in large quantities.

4. Pesticides or other unfa­vourable chemicals are sometimes used to preserve the turmeric or improve its appearance. These chemicals can pose a serious health risk if consumed and reduce tur­meric’s quality.

5. Another adulterant to reduce product cost is synthetic curcumin which can be detected through Nuclear Magnetic Reso­nance (NMR) spectroscopy. Synthet­ic curcumin is a chemically manufac­tured version of the compound, and it can contain impurities or contami­nants that can be harmful. Synthetic curcumin is considered a hazard because it can negatively affect human health. Additionally, synthetic curcumin has different properties than natural curcumin, potentially leading to inconsistent or ineffective results when using synthetic curcum­in in dietary supplements or medical treatments.

• Even raw or wild turmeric is added to the powder.

These make turmeric hazardous and unfit for consumption.

It is difficult to tell the contami­nation just by looking at the powder. However, you can perform a few tests to detect the problem.

Simple Home Tests

Here are the easy tests you can do at home:

To identify turmeric adulteration by smell and taste, here are some steps you can follow:

Smell:

• Genuine turmeric should have a warm, earthy and slightly bitter scent.

• Adulterated turmeric may have a chemical or musty odour.

Taste:

• Genuine turmeric should have a slightly bitter and slightly spicy flavour.

• Adulterated turmeric may have a bitter or harsh taste that dif­fers from the natural flavor.

Palm Test

• Rub a little turmeric pow­der on your palm for fifteen seconds. Turn the palm upside down.

• Pass: Pure turmeric will stick to the palm and give a yellow stain.

• Fail: If most of the pow­der falls, it is adulterated.

Water Test

• Take a glass of warm water and put a teaspoon of turmeric powder.

• Pass: After fifteen minutes, if the powder settles down at the bottom and stays pale yellow, it is genuine.

• Fail: If the powder does not settle down and the water turns dark yellow, the powder is adulterat­ed.

Lead Chromate Test

• Mix a teaspoon of turmer­ic in water.

• Fail: Lead chromate is a water-soluble colour and will in­stantly release a yellow tinge into the water.

Turmeric Root Test

• If you want to test a turmeric rhizome (the root, not its powder), put it on paper and sprinkle some water on it.

• Fail: If it is coated with some artificial colour, you will notice the colour coming off.

Laboratory Tests

The following tests are harder to do at home and are best done in a laboratory:

Starch Test

• View the powder under a microscope.

• Pass: Turmeric particles are large and yellow, with sharp edges.

• Fail: Adultarant starch particles are small, white, and round.

Metanil Yellow Test

• Put a teaspoon of turmeric in hydrochloric acid and shake the mix carefully.

• Fail: The mixture will turn pink if metanil yellow is present.

Chalk Powder Test

• Put a teaspoon of turmeric in hydrochloric acid and shake the mix carefully, as above.

• Fail: If bubbles are formed in the mix, it indicates the presence of chalk powder.

Summary

• One can minimise the possibility of adulterated turmeric by buying turmeric roots and grinding them at home. You still have a con­tamination risk but the chances are much less.

• If that is too cumbersome, look for a reliable brand of turmeric powder.

• Please don’t buy loose powder from the market.

• Unfortunately, you have no control over the turmeric used in the food you eat outside your house. Avoid eating food cooked in low-end, cheap food joints.

The writer is a Professor of Na­turopathic Healthcare, a Medical Journalist, and a science writer. President, Nyarkotey University College of Holistic Medicine & Technology (NUCHMT)/Afri­can Naturopathic Foundation, Ashaiman, Ghana. E. mail: pro­fessor40naturopathy@gmail.com. Visit-profnyarkotey.com for more.

BY PROF. RAPHAEL NYARKOTEY OBU