Adulterants In Turmeric Powder & How To Avoid Them

Adulterated turmeric powder is a concern in the spice industry, and various types of contaminants can be found. As the beneficial properties of turmeric and its numerous health benefits have become more well known, the market for this spice with medicinal qualities is in higher demand. Manufacturers of turmeric powder products may not always have the best integrity, while others will make quality and the integrity of their product’s manufacturing and procuring practices the hallmark of their business.

How can we tell the difference? What do we need to know to get good turmeric powder (called Haldi in Indian traditions) that isn’t laced or contaminated with impurities? Read on to learn what can happen and how you can assure you are getting a quality turmeric powder.

What is Adulteration?

Adulteration refers to the intentional or unintentional addition of substances that are not disclosed and don’t meet quality standards. I became concerned about this after accidently buying a 5# bag of turmeric on Amazon that was fairly inexpensive. This led to me doing further research and a lot of recipe experimentation with turmeric.

Consuming adulterated turmeric not only means you are not getting the health benefits you were seeking, it could also be a cause for issues like upset stomach or toxic lead levels.

The types of findings in turmeric powder that you would not want or expect can include:

Fillers

Starch, Flour, Chalk, or Talc: Some unscrupulous suppliers may add inexpensive fillers like starch, flour, or talc to increase the weight of the turmeric powder and reduce production costs.

  • Chalk Test:
    • Chalk may bubble if you add lemon juice to the powder in water. The acid with the calcium carbonate in the chalk creates fizzy bubbles.
      • A teaspoon of turmeric powder in a test tube filled with water and a few drops of hydrochloric acid would have the same effect.
    • Turmeric powder with chalk in it can also cause indigestion. This is because calcium carbonate is alkaline, and when consumed, can cause the stomach to increase its acid production in response to the more basic, or higher pH, chalk. For similar reasons, I do not recommend alkaline water.

Starch Test: Place the turmeric powder under a microscope to check for the presence of starch. Turmeric will look more yellow and angular in appearance compared to paler whitish, smaller, and rounder starch fillers. At the time of this writing, my son will be getting a microscope for Christmas. Hopefully he thinks this is as cool as I do. I will then be able to update this post with an original image of the findings, if I figure out how to photograph it.

Dyes

Sudan Red: This synthetic dye that has been used illegally to enhance the color of certain food products, including spices like turmeric powder. Its use is prohibited in many countries due to its potential health risks. This dye has been found to contain harmful carcinogenic compounds which can pose serious health hazards when ingested.

Metanil Yellow: This synthetic dye is sometimes illegally added to turmeric powder to enhance its yellow color. Metanil yellow is not approved for use in food, is considered poisonous, and has been shown to damage internal tissues.

Metanil Test: To test for the presence of metanil yellow, place a pinch of turmeric powder in a test tube, add a few drops of strong hydrochloric acid, and violently shake it.

  • If the solution becomes pink, this indicates the existence of metanil. Consuming turmeric powder that is high in metanil will make you feel nauseated, create stomach problems, and cause food poisoning.

Water Test: You probably don’t have hydrochloric acid at home. Neither do I. But we all have water. Add a teaspoon of turmeric powder to a glass of water and after stirring, allow it to settle for an hour or so. You can probably already tell at 10-15 minutes if the turmeric powder is settling to the bottom. A dark yellow tint to the water suggests it is adulterated.

According to Consumer Lab:

If a dye has been added to turmeric, putting the turmeric in a glass of water (the “water test”) may allow the dye to separate from the turmeric powder which will generally sink to the bottom of the glass (some may float near the top). The water test may not be appropriate for extracts because some products contain emulsifiers and other additives to solubilize the extract in water (so that it neither sinks nor floats).

The “acid test” (such as mixing turmeric in lemon juice) is proposed as a way to determine if a dye known as metanil yellow (or Matalan), has been added to turmeric because acid doesn’t change the yellow color of turmeric but it will turn change metanil yellow to pink.

However, unlike the laboratory tests that ConsumerLab conducts, neither of these tests will tell you how much of an adulterant (or heavy metal, such as lead) is present, nor amounts of curcumin or total curcuminoids.

So how did my 5# bag of turmeric do using this test?

The tests Consumer Labs suggested above are simply enough to do at home. So I did. According to the ingredients label on my bag of turmeric bought on Amazon from ‘Organic Express’, the turmeric is a product of India, Indonesia, Madagascar, Nigeria, and Sri Lanka. That’s a lot of places, but not Bangladesh.

Below are two glasses. On the left is turmeric and water, on the right turmeric, water, and the juice of a lime (we had no lemons). The top is just after mixing and below that is after 12 hours.

This product was possibly dyed. I will get a better sourced sand third party tested one and update this post.

Lead

Lead contamination probably freaks me out the most. It lowers your IQ, and a low IQ makes everything harder. Lead is a toxic heavy metal that poses serious health risks, especially with prolonged exposure. Lead will not be at a true zero, but parameters have been set to prevent toxicity.

Contamination Not Uncommon In Many Powdered Supplements

Unfortunately, testing is showing us that the presence of heavy metals are not uncommon to find in commonly consumed nutrition supplements. Protein powders, green drink mixes, and magnesium supplements are some that have been found to have contaminants like lead, cadmium, and arsenic. In the Clean Label Project’s study, 70-74% of plant based protein powders had measurable amounts of lead.

Many factors can contribute to lead levels:
  • Lead Chromate Pigments: In turmeric powder, lead chromate, a yellow pigment, has been found as an adulterant to enhance its color. This has been found in 11-26% of turmeric samples from Bangladesh, presumably added to compete with brighter colored turmerics from India.
  • Raw Ingredient Quality: Lead contamination can originate from the raw ingredients used in the production of powdered nutrition products. If the source of ingredients, such as fruits, vegetables, grains, or turmeric, in this case, is grown in areas with high environmental lead levels, the contamination can be transferred to the final product.
  • Soil and Water Contamination: Lead is a naturally occurring element, but human activities, such as industrial processes, mining, and the use of leaded gasoline, have contributed to environmental contamination. Plants used in nutrition products can absorb lead from contaminated soil or water, which may result in elevated lead levels in the final product.
  • Processing Methods: Certain processing methods, especially those involving grinding, milling, or concentrating, can potentially increase the concentration of lead in powdered products. If the processing equipment or facilities are not adequately monitored for lead contamination, it can contribute to the problem.
  • Supply Chain Issues: A complex supply chain can increase the likelihood of lead contamination. If there are gaps in quality control and monitoring throughout the supply chain, it becomes challenging to trace and address potential sources of contamination.
  • Lack of Regulation and Oversight: In some cases, there may be inadequate regulatory standards or insufficient oversight regarding lead levels in certain food products. This can allow products with elevated lead content to enter the market.
  • High Absorption of Lead in Certain Plants: Some plants, particularly leafy greens, may have a higher propensity to absorb lead from the soil. If these plants are used as ingredients in powdered nutrition products, there is a higher risk of lead contamination.
  • Imported Ingredients: Powders and supplements often contain ingredients sourced from various regions globally. In some cases, countries may have different regulations and standards for monitoring lead levels in food products, contributing to variability in contamination risk.

Lead Chromate Test: To test the presence of lead chromate in turmeric powder, mix a teaspoon of turmeric powder with water. It will instantly leach streaks of water-soluble colour into the solution, indicating the presence of lead chromate.

The water test does not rule out all types of lead content. For this reason only rely on third party testing as an assurance against lead.

Third Party Heavy Metal Testing

The USDA Organic food label is often sought by consumers as an assurance of wholesome and ‘clean’ eating choices. While the USDA does prohibit the use of heavy metals for organic produce growers, a USDA organic seal does not imply the product has been tested for heavy metals.

Look for third party heavy metal testing. Consumer Lab is one such third party testing resource.

Messaging around quality and purity of products can be misleading, with marketing and packaging clouding our perceptions and judgement. Try searching web pages for the text ‘third party testing’ in a products frequently asked questions area or contact the company with any questions on the matter.

Dilution with Inferior Turmeric Varieties

Perhaps the least of all evils, turmeric powder may be mixed with varieties of turmeric that don’t have the curcumin compound levels sought out by consumers. It is the curcuma longa variety, known for its culinary and medicinal properties that is typically used interchangeably with ‘turmeric’. However, note that there are different varieties and species within the Curcuma genus, and they may have variations in appearance, flavor, and chemical composition.

  1. Curcuma longa (Turmeric): This is the most common and widely recognized variety of turmeric. It is known for its vibrant yellow color, warm and slightly bitter flavor, and is a key ingredient in many cuisines, particularly in South Asian and Middle Eastern dishes. Curcuma longa is also valued for its potential health benefits, attributed to its active compound curcumin, which has anti-inflammatory and antioxidant properties.
  2. Other Varieties of Turmeric: There are several other species and varieties within the Curcuma genus, each with its own characteristics. Some of these may be known by different names, such as wild turmeric (Curcuma aromatica) or black turmeric (Curcuma caesia). These varieties might have different colors, flavors, and aromatic profiles compared to Curcuma longa.

When purchasing turmeric, especially in spice form, it is often labeled simply as “turmeric” without specifying the variety. If you’re interested in the specific characteristics of the turmeric you’re using, you may need to inquire with the supplier or choose a reputable source that provides more detailed information about the product.

Contaminated Turmeric Powder

The manufacturing process is another critical point when looking for quality turmeric powder.

  1. Moisture Content and Mold Contamination:
    • High Moisture Content: Turmeric powder with high moisture content is susceptible to mold growth. Mold can not only compromise the quality of the spice but also pose health risks.
  2. Microbial Contamination:
    • Bacterial or Fungal Contamination: Poor handling, storage, or inadequate drying processes can lead to microbial contamination in turmeric powder. This can affect its safety and shelf life.

Finding Unadulterated Turmeric Powder

To ensure that you are purchasing high-quality, unadulterated turmeric powder, consider the following:

  • Buy from Reputable Sources: Purchase turmeric powder from reputable brands or suppliers known for their commitment to quality.
  • Check for Certification: Look for products that have been tested and certified by reputable organizations for quality and purity.
  • Read Labels: Check product labels for information on testing, certifications, and any added ingredients.

A Few Brands To Consider

Quality turmeric powder can be confidently found by looking for products from companies that have undergone third party testing. You may also consider subscribing to Consumerlab.com, which offers a membership that allows you to see results of their quality testing performed on numerous supplements on the market. While Consumerlab is really better suited for supplements rather than spices, they did test three commonly available turmeric spice products.

Surprisingly, Wal-Mart’s Organic Great Value Ground Turmeric has less lead than the other two tested brands, McCormick and Frontier Co-op brand’s, though they were all in acceptable levels. The tested products did not differ significantly in curcuminoids, and Wal-Mart’s had the best price.

You could be a consumer advocate for products sold at Walmart, or support one of these brands below:

  • Navitas Organics sources their turmeric from Myanmar, where less than 4% of the world’s turmeric is exported from and it is grown organically. They also have third party testing done.
  • Feel Good Superfoods also does third party testing. You may find their products in common drug stores, on Amazon, or ar Walmart. They also give back to Vitamin Angels and Water Purification Project.
  • American Turmeric makes their turmeric powder in small batches, and third party lab tests each batch to assure you get a lead free turmeric powder.

Extracts of Curcumin Safer Bet Compared to Turmeric Powder

If you just looking for the benefits of turmeric without incorporating it into your food, consider using a curcumin extract supplement. It’s really the best and most likely way you will absorb enough of turmeric’s active compound, curcumin, to have significant effects. For more information about curcumin supplements and the best and latest in curcumin supplement advancements, read this post.

Making Your Own Turmeric Powder

Making your own turmeric powder may be the most certain and most affordable way to have a reliable and fresh, good tasting product. To make your own turmeric powder at home, read this post with instructions.

After going through the experience of purchasing turmeric powder on Amazon, feeling that it tasted a bit bitter compared to that which I made from fresh turmeric root from the grocery store, and finding signs of possible adulteration with simple tests at home, it is my best suggestion to either:

  • Make your own fresh turmeric powder
  • Buy from one of the reputable and third party tested companies

References

Parvathy VA, Swetha VP, Sheeja TE, Sasikumar B. Detection of plant-based adulterants in turmeric powder using DNA barcoding. Pharm Biol. 2015;53(12):1774-9. doi: 10.3109/13880209.2015.1005756. Epub 2015 Apr 8. PMID: 25853978.

Bandara SB, Towle KM, Monnot AD. A human health risk assessment of heavy metal ingestion among consumers of protein powder supplements. Toxicol Rep. 2020 Aug 21;7:1255-1262. doi: 10.1016/j.toxrep.2020.08.001. PMID: 33005567; PMCID: PMC7509468.

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Anne Marie Berggren RDN, MS, CDN, CNSC is a Registered Dietitian with a Master's Degree in Nutrition, training in integrative and functional nutrition, nutrition for mental health, obesity and weight management, is a board certified nutrition support clinician, and an adjunct professor for the Stony Brook Graduate Nutrition Program teaching advanced clinical nutrition.

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