News

This study (open access) investigated turmeric adulteration with lead chromate across five eastern Indian states through a combination of sample analysis and qualitative supply chain assessments. Lead chromate is a known adulterant of ground spices including turmeric, used to enhance the colour and therefore infer a higher quality or mask dilution.   The researchers collected 503 turmeric samples from 34 cities and conducted 128 stakeholder interviews between 2021-2023. In total, 30% of turmeric samples exceeded India’s permissible lead limit of 10 µg g⁻¹.

They also performed a population-level risk assessment and modelled the cost to India’s health system and economy, assuming the adulteration rate could be extrapolated across the region.  They concluded that halting the practice of turmeric adulteration with lead chromate could increase child IQ by up to 2.3 points, resulting in future income gains of US$ 239 million to 1.6 billion annually in the Bihar region alone. If cardiovascular disease mortality reductions are included, there would be an additional benefit of approximately US$ 430 million to 2.8 billion per year.

Photo by Tamanna Rumee on Unsplash

The Royal Society of Chemistry’s “Advances in the Chemical Analysis of Food V” conference, last week, included a number of talks and posters on various aspects of food authenticity testing.  The keynote, from Professor Chris Elliot, was on the use of data fusion to improve untargeted classification models by aggregating information from multiple analytical approaches.

One presentation, from Nathan O’Neill at the University of East Anglia (a FAN Centre of Expertise) raised new suspicions about turmeric authenticity.

Conventional wisdom (and Seasoning & Spice Association guidance) is that a significant vulnerability point for turmeric adulteration is when the roots are ground.  However, in this case, Nathan sourced intact roots from both UK and overseas online sellers.  Only reputable sellers were used but there were no prior assumptions about sample authenticity.  Chemometric feature selection and modelling (using two orthogonal untargeted analytical techniques) highlighted some of the samples whch were clear outliers.  These outlying classifications were consistent between replicate analyses and between the two orthogonal test methods.

The next planned research stage is to build reference databases for each method, then check if these outliers are mislabelled or if it reflects honest variation within turmeric taxonomy and production.

Details of the conference programme and speakers can be found here

This paper (open access) reviews the history and exportation of turmeric in Africa and the safety issues of some toxic adulterants.

Priority adulterants were determined from global food safety alerts. A systematic bibliographic search was performed to identify appropriate methods and techniques for authentication and safety testing. The quality of each study was assessed according to PRISMA guidelines/protocol.

The authors report that African turmeric exportation is on the rise due to recent insights into the suitability of local cultivars, soil and climate for growing high-quality turmeric. There are limited data on turmeric adulteration for domestic consumption and export markets..

Global alert databases revealed lead chromate as the top hazard identified of all adulterants. Current techniques to detect adulterants are laboratory-based, and while efficient, there is a need for more rapid, field-friendly, non-destructive analytical tools.  The authors consider that – if lead chromate is considered to be the main tisk - then pXRF would be ideally suited as a field-based test in Africa. In the hope that it could be further developed and calibrated to detect below the regulatory level of 1.5 mg/kg lead in turmeric powder. There would be a need to cross-check pXRF screening results against a validated and accredited ICP-MS method as a reliable confirmatory tool.

Photo by Md Shakil Photography on Unsplash

Adulteration is a growing food safety concern worldwide. Previous studies have implicated turmeric as a source of lead (Pb) exposure due to the addition of lead chromate (PbCrO4), a yellow pigment used to enhance brightness. This study aimed to assess the practice of adding yellow pigments to turmeric and producer- consumer- and regulatory-factors affecting this practice across the supply chain in Bangladesh.

Nine major turmeric-producing districts of Bangladesh, as well as two districts with minimal turmeric production, were identified and visited. In each district, semi-structured interviews were conducted and informal observations were made with individuals involved in the production, consumption, and regulation of turmeric. Perceptions of and preferences for turmeric quality.

Samples of yellow pigments and turmeric were collected from the most-frequented wholesale and retail markets. Samples were analysed for Pb and chromium (Cr) concentrations via inductively coupled plasma mass spectrometry and x-ray fluorescence.

The study found evidence of PbCrO4-based yellow pigment adulteration in 7 of the 9 major turmeric-producing districts.

Turmeric wholesalers reported that the practice of adding yellow pigments to dried turmeric root during polishing began more than 30 years ago and continues today, primarily driven by consumer preferences for colourful yellow curries.

The results from this study indicate that PbCrO4 is being added to turmeric by polishers, who are unaware of its neurotoxic effects, in order to satisfy wholesalers who are driven by consumer demand for yellow roots. The study recommends immediate intervention that engages turmeric producers and consumers to address this public health crisis and ensure a future with Pb-free turmeric.

Read full publication.