Scientists Uncover Cancer-Causing Chemicals in Common Foods

The study uses an advanced QuEChERS–GC–MS detection method to uncover hidden carcinogens in cooking oils and meats.

Many people today are placing greater emphasis on their overall health, turning daily workouts and calorie-tracking tools into regular habits. As part of this shift, more individuals are choosing diets that feature nutrient-rich foods such as fruits and vegetables.

Although these foods are widely viewed as healthy, they can still contain polycyclic aromatic hydrocarbons (PAHs) (hydrophobic organic compounds comprising multiple fused aromatic rings) when exposed to contamination or when cooked through heating, smoking, grilling, roasting, or frying. PAHs can enter plant-based foods (such as fruits and vegetables) through atmospheric deposition from vehicle exhaust and industrial emissions, irrigation with contaminated water, or uptake from polluted soil, where they may accumulate on the surface or within edible tissues.

In animal-based foods, such as meat and fish, PAHs are often generated during processing and cooking, particularly when food is exposed directly to open flames, smoke, or very high temperatures.

Foods commonly found to contain higher levels of PAHs include:

• Smoked or grilled meats and fish (e.g., smoked salmon, bacon, barbecued chicken, charred beef).
• Roasted or charred plant foods (roasted coffee beans, dark-roasted nuts, charred vegetables, burnt toast).
• High-heat processed oils and fats (reused frying oils, highly refined vegetable oils).
• Heat-processed grain products (roasted cereals, malted grains, toasted snacks).
• Produce exposed to environmental pollution (leafy greens, root vegetables, and fruits grown near roadways or industrial areas).
• Smoke-dried teas and herbs (black tea, green tea, certain herbal teas).

Cooking Processes That Generate PAHs

During grilling, barbecuing, and pan frying, PAHs can form from the incomplete combustion of fats and other organic components and tend to concentrate in charred or heavily browned areas. Smoked and roasted products, including smoked meats, smoked fish, certain cheeses, and roasted coffee, frequently show measurable PAH levels. Processed foods that undergo intensive thermal treatment, such as some baked goods and cereal products, can also contain PAHs, especially when surfaces are darkly browned.

Because certain PAHs are known carcinogens, their presence in such a wide variety of foods raises important public health concerns and highlights the need for monitoring and mitigation across the food supply chain.

To protect consumers, it has become essential to efficiently extract, identify, and measure PAHs in food. Common extraction methods, including solid-phase, liquid-liquid, and accelerated solvent extraction, are generally affordable but often slow, labor intensive, and not environmentally friendly.

In recent years, researchers have highlighted the QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) method as a promising alternative for isolating organic compounds. This approach shortens analysis time, increases accuracy and recovery, and simplifies the overall preparation process, offering a safer and more dependable option for PAH testing.

Study Overview and Objectives

A recent study conducted by researchers in the Department of Food Science and Biotechnology at Seoul National University of Science and Technology, led by Professor Joon-Goo Lee, applied the QuEChERS method to measure eight PAHs (Benzo[a]anthracene, Chrysene, Benzo[b]fluoranthene, Benzo[k]fluoranthene, Benzo[a]pyrene, Indeno[1,2,3-cd]pyrene, Dibenz[a,h]anthracene, and Benzo[g,h,i]perylene) in food. The results of their work were published in the journal Food Science and Biotechnology.

The researchers extracted PAHs using acetonitrile. This was followed by purification via different methods involving various combinations of sorbents. The researchers validated the QuEChERS extraction method through a number of food matrices, finding that the calibration curves for the eight PAHs demonstrated remarkable linearity, ­with the R² value exceeding 0.99.

Further, the gas chromatography‒mass spectrometry analysis revealed that the limits of detection ranged from 0.006 to 0.035 µg/kg, while the limits of quantification ranged from 0.019 to 0.133 µg/kg. Notably, recoveries ranged from 86.3 to 109.6% at 5 µg/kg, 87.7 to 100.1% at 10 µg/kg, and 89.6 to 102.9% at 20 µg/kg, with precision values between 0.4 and 6.9% in all food matrices.

Significance and Industrial Impact

Prof. Lee reveals, “This method not only simplifies the analytical process but also demonstrates high efficiency in detection compared to conventional methods. It can be applied to a wide range of food matrices.”

In the industrial sector, this method could be used for inspecting food products for safety management. Furthermore, it is expected to lead to cost reduction and improved safety for workers.

“Our research can improve public health by providing safe food. It also reduces the use and emission of hazardous chemicals in laboratory testing,” concludes Prof. Lee.

Overall, this study showcases that the developed PAH analysis method based on the QuEChERS approach is environmentally friendly, rapid, and accurate.

Reference: “QuEChERS method development for the GC–MS analysis of polycyclic aromatic hydrocarbons in food” by Jihun Jeong, Minju Koo and Joon-Goo Lee, 5 June 2025, Food Science and Biotechnology.
DOI: 10.1007/s10068-025-01910-2

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