by Holly Lee, PhD, Staff Scientist – Food, SCIEX
Pretty much everyone loves to eat. And for many of us, loving food eventually leads to cooking—sometimes with great success, sometimes with less. Over the years, our palates expand, and our kitchens start to reflect the increasingly global nature of what we eat. Spices that once felt exotic—turmeric, paprika, cumin—now sit comfortably in everyday cupboards. In my own kitchen, paprika—a great source of vitamin C—is a staple. I make roasted chicken thighs that my son loves, and paprika is always part of the recipe. Turmeric shows up less often, and cumin occasionally. I wouldn’t call myself the most adventurous cook—my husband takes that title—but like many people, I rely on spices every day to bring flavor to family meals.
That’s why the methods we’ve developed at SCIEX for analyzing spices struck close to home. The spices being tested—paprika, turmeric and blends used in dishes like couscous—are the same kinds of ingredients many of us use regularly. They’re also ingredients we trust. When I add paprika to a meal I’m feeding my son, I assume what’s in the jar is exactly what the label says it is—nothing more, nothing less.
Yet recent analytical testing of real-world spice samples suggests that assumption doesn’t always hold.1–4 In several cases, researchers detected undeclared additives—including food dyes that are restricted or outright banned in many countries. One particularly concerning example is Sudan IV, an industrial dye classified as a potential carcinogen, detected in paprika samples.1 Our scientists also detected bixin—an additive derived from annatto—in a couscous spice blend.1 Another of our studies and regulatory checks also found color additives, such as Sunset Yellow and metanil yellow, in jaggery—a sugar commonly used in South Asia as a healthy alternative to refined white sugar.2,4
To be clear, most of the spice samples tested were completely clean. But the presence of these substances in any samples highlights a persistent vulnerability in the global food supply chain. Spices often travel long distances—from farms to processors to exporters to retailers—and at multiple points along that path, there are opportunities for adulteration, intentional or otherwise. Sometimes dyes are added to enhance color and perceived freshness. In other cases, additives may be introduced through cross-contamination or processing shortcuts.
For food safety regulators and analytical laboratories, these findings underscore an ongoing challenge: detecting compounds that traditional screening methods can miss. Increasingly, the solution lies in more advanced analytical technologies—particularly liquid chromatography–mass spectrometry (LC-MS), which is capable of identifying trace-level contaminants and unexpected compounds in complex food matrices. Advanced tandem LC-MS (LC-MS/MS) methods are revealing a level of detail about spice composition that earlier techniques often overlooked. And for those of us who cook with and consume these ingredients, that kind of analytical precision matters more than ever.
Why are spices particularly vulnerable to adulteration?
Spices have historically been targets for adulteration because they are sold as powders or blends, making visual inspection difficult. Color is especially important for consumer perception—bright turmeric, deep red paprika, or richly colored curry powders are often seen as indicators of quality. This economic incentive has led some suppliers to add artificial dyes to enhance appearance or compensate for natural color loss during processing and storage. Artificial colorants are attractive from a manufacturing perspective because they are inexpensive, chemically stable, and highly effective at intensifying color.
However, not all dyes are permitted in food, such as Sudan dyes, which are lipophilic azo dyes with strong color intensity, colorfastness, and low cost—characteristics that unfortunately make them appealing additives.1 These dyes are also used industrially to color materials such as fuels and waxes.1 They have been linked to carcinogenic metabolites, which is why they are banned from foods in the European Union and many other jurisdictions.1,5 Nevertheless, these dyes have been found in various food products, including spices and tomato sauces, in recent years.1,6
Figure 1: Positive detection of Sudan IV in a real-world paprika sample using SWATH DIA (data-independent acquisition) with the X500R QTOF system. The identification of the banned food dye was confirmed based on a low precursor mass error (-2.5 ppm, left panel, A), a good match to the theoretical isotope pattern (middle panel, B), and a positive hit for Sudan IV using the in-house MS/MS spectral library with a “Fit” score of 99.5 (right panel, C).
Artificial dyes permitted for certain food applications can also raise concerns when used improperly. Some have been associated with health effects ranging from potential carcinogenicity to behavioral impacts in children, prompting increasing regulatory scrutiny and calls for reduced use in foods.1,7 Against this backdrop, analytical testing has become the front line in protecting consumers.
Testing real-world spices reveals hidden additives
Figure 2: Positive detection of bixin in a couscous spice blend sample using SWATH DIA with the X500R QTOF system. Detection of the banned food dye was shown by a low mass error (0.05 ppm, left panel), a good match to the theoretical isotope pattern (middle panel) and positive hit for bixin using the in-house MS/MS spectral library with a “Fit” score of 92.3 (right panel).
Recent technical studies evaluating commercial spice samples demonstrate how modern analytical techniques are uncovering contaminants that might otherwise remain undetected.1,2 In one screening study, researchers analyzed more than 80 spice products purchased from supermarkets and markets using an LC-MS method on a quadrupole time-of-flight (QTOF) instrument capable of detecting dozens of food dyes simultaneously.1 The results were mostly reassuring—most samples showed no detectable illegal additives.
But two findings stood out. The first was the detection of Sudan IV in a paprika sample (see Figure 1). Confirmation of the compound relied on several analytical indicators: low mass error for the precursor mass (-2.5 ppm [and -3.4 ppm for the m/z 224.118 Da fragment mass]), good agreement with the theoretical isotopic pattern, and a positive hit and high “Fit” score for the MS/MS mass spectra against a spectral library.1 The spectral match achieved a “Fit” library score of 99.5%, leaving little doubt about the identity of the compound. The same screening method also detected, with high confidence, bixin—a natural colorant derived from the seeds of the tropical achiote tree—in a couscous spice blend (see Figure 2).1 Although bixin itself is permitted in many food contexts, its presence in a product without label disclosure raises potential regulatory questions depending on jurisdiction.
Figure 3: Detection of Sunset Yellow in a commercial jaggery sample. Quantifier (blue) and qualifier (pink) traces are shown with ion ratio tolerance lines.
A separate targeted study focusing on artificial dyes in turmeric and jaggery sugar found additional evidence of undeclared colorants.2 Among several tested products, Sunset Yellow was detected in a jaggery sample at 392 ng/g, with analyte detection being confirmed using the ion ratio relative to the analytical standard (see Figure 3). These findings do not imply widespread contamination across the spice market. However, they demonstrate how even a small number of positive results can reveal weaknesses in supply-chain oversight.
Why traditional testing can miss adulterants
Historically, food testing for dyes relied on methods such as high-performance liquid chromatography with ultraviolet detection (HPLC-UV). While useful for targeted analysis, these techniques have limitations when applied to complex matrices like spices. Spices contain a wide range of natural pigments, oils, and other organic compounds that can interfere with detection. In addition, some adulterants are present only at trace levels or appear in unexpected combinations. Even small amounts may still matter for public health: research examining food dyes and children’s neurological outcomes has linked certain synthetic color additives to increased hyperactivity and attention-related behavioral effects in susceptible children, suggesting that low-level, undeclared exposures could be significant for some consumers.7
Modern LC-MS/MS methods overcome many of these challenges by combining chromatographic separation with highly selective mass detection. In the screening approach used for spice analysis, liquid chromatography first separates compounds based on their chemical properties. The mass spectrometer then identifies them by measuring exact molecular mass and fragmentation patterns. This approach allows laboratories to simultaneously screen for dozens or even hundreds of compounds, including those that were not originally targeted.
One powerful variant of this approach is SWATH DIA (data-independent acquisition) . In this method, tandem mass spectra are collected for all precursor ions across a series of mass windows, ensuring that fragmentation data is recorded for every detectable compound in the sample. By capturing MS/MS spectra for all compounds rather than only pre-selected targets, SWATH DIA enables both targeted and non-targeted screening in a single run.1 This capability is particularly valuable when investigators do not know which adulterants might be present.
High-confidence identification and sensitivity
Advanced LC-MS platforms provide multiple layers of confirmation to reduce false positives and improve confidence in analytical results. For example, detection of Sudan IV in paprika relied on several independent criteria: accurate precursor mass measurements within a few parts per million, agreement with theoretical isotope patterns, and spectral library matching.1 These orthogonal criteria help distinguish genuine detections from analytical artifacts. In validation studies of just one of several LC-MS/MS dye screening methods, the false positive rate was effectively 0%, with only minimal false negatives observed for a small subset of analytes.1 Such reliability is critical when analytical results may trigger regulatory investigations or product recalls.
Another advantage of LC-MS/MS methods is their extraordinary sensitivity. In targeted dye analyses of turmeric and jaggery samples, detection limits in solvent standards reached 0.02–0.2 ng/mL, enabling identification of contaminants at extremely low concentrations.2 This level of sensitivity allows laboratories to detect trace adulteration that might be invisible to traditional techniques. It also enables simpler sample preparation procedures. For example, dilution-based extraction methods can reduce matrix effects without sacrificing sensitivity because the mass spectrometer is capable of detecting minute amounts of analyte.2
The bigger picture
The discovery of unexpected additives in spices fits within a broader global concern about food authenticity and contamination. Modern food supply chains are complex and often span multiple countries, involving numerous intermediaries between farm and consumer. While regulatory frameworks exist in most major markets, enforcement can vary, and adulteration can occur intentionally or unintentionally at various stages. Moreover, consumers are increasingly turning to the global marketplace online, making purchases directly—often in bulk—from abroad, where regulatory frameworks may differ considerably.
Colorants represent just one category of potential contaminants. Other studies have highlighted risks ranging from undeclared artificial sweeteners in beverages to toxic plant alkaloids in adulterated spice powders.8,9 For example, LC-MS/MS screening methods have been developed to detect highly toxic aconitine alkaloids in spice products contaminated with Aconitum plant material.9 In one case study, adulterated samples contained milligram-per-gram levels of aconitine, demonstrating how analytical testing can identify hazards to avoid widespread exposure.9 Taken together, these examples underscore the need for robust analytical surveillance across the food supply.
Implications for regulators and industry
For regulators, the continued development of high-resolution LC-MS/MS screening tools offers both opportunities and challenges. On one hand, advanced instruments enable laboratories to detect previously hidden adulterants with unprecedented sensitivity and confidence. On the other hand, these capabilities may reveal problems that were previously invisible, increasing the need for coordinated regulatory responses.
For food manufacturers and importers, the message is clear: analytical verification of ingredients is becoming essential. Routine LC-MS/MS screening can help identify contamination early in the supply chain, reducing the risk of costly recalls and protecting brand reputation. In many cases, manufacturers are also responding to consumer pressure by voluntarily reducing synthetic dyes or switching to natural colorants. Yet even natural additives must be accurately labeled and used in compliance with regulatory limits.
A technology-driven future for food safety
The ongoing evolution of analytical instrumentation is transforming how food safety laboratories operate. High-resolution mass spectrometry, automated spectral libraries, and both targeted and nontargeted acquisition strategies now allow laboratories to screen for hundreds of compounds simultaneously. These advances are particularly important in complex products such as spices, where adulteration may involve unexpected chemicals introduced at trace levels.
The detection of Sudan IV in paprika, Sunset Yellow in turmeric and jaggery products, and bixin in a spice blend demonstrates the value of this approach. Each discovery required sensitive instrumentation, sophisticated data analysis, and robust reference libraries. Importantly, the majority of tested products in these studies showed no illegal dyes, suggesting that many producers are complying with regulations. But the few exceptions illustrate how easily undeclared additives can enter the supply chain without rigorous testing.
Beyond detection, science and technology are also playing a growing role in developing safer alternatives to synthetic colorants. Researchers are increasingly exploring plant-derived pigments—such as carotenoids, anthocyanins, curcuminoids, and betalains—as natural dyes that can replace artificial additives in foods and food manufacturing. Advances in analytical chemistry, biotechnology, and process engineering are enabling scientists to identify promising pigment molecules, optimize extraction and purification methods, and ensure stability during processing and storage. Techniques such as LC-MS/MS and metabolomic profiling help characterize these compounds and monitor their purity, while fermentation and bioprocessing technologies are opening new pathways for scalable production.10,11 Together, these innovations are helping the food industry develop natural colorants that meet both regulatory expectations and consumer demand for cleaner labels.
As global food systems continue to expand, the need for reliable analytical monitoring will only grow. For laboratories, regulators, and manufacturers alike, it is clear that advanced LC-MS/MS technologies are becoming indispensable tools for safeguarding the food supply. By revealing contaminants that once slipped through conventional testing, these technologies are helping ensure that the spices consumers sprinkle into their meals contain exactly what the label promises—and nothing more.