The Invisible Chemicals Lurking in the "Aroma of Browning": How to Consider Carcinogenic Risks in Everyday Foods

The browning on freshly grilled meat, the savory crust of fried foods, the deep aroma of smoked foods.
These are all elements that whet the appetite, but behind them, invisible chemical reactions are taking place.

A research team from Seoul National University of Science and Technology in South Korea focused on polycyclic aromatic hydrocarbons, or PAHs, which may be present in everyday foods. PAHs are a group of organic compounds with multiple aromatic rings, some of which have been linked to carcinogenicity. In the case of food, they can be generated during cooking processes involving high temperatures or smoke, such as grilling, roasting, smoking, and frying.

The significance of this study lies not in unnecessarily alarming about "what is dangerous," but rather in how quickly, accurately, and conveniently PAHs present in trace amounts in foods can be measured. In the world of food safety, it's crucial not only to discuss dangers but also to measure, compare, and continuously monitor them.

What are PAHs? The Chemicals Created by "Smoke" and "Browning"

PAHs are not exclusive to food. They are generated in various situations, such as automobile exhaust, tobacco smoke, industrial activities, and the incomplete combustion of wood or fossil fuels. In food, PAHs are said to increase when meat fat or juices drip onto a hot grill, charcoal, or open flame, producing smoke whose components adhere to the surface of the food.

Particular caution is advised for direct flame cooking or prolonged high-temperature cooking. Flames rising during a barbecue, causing the surface of the meat to blacken, or exposing food to smoke during smoking, or continuously using oil at high temperatures can increase the risk of chemical generation in exchange for savoriness and flavor.

However, it's important to note that this is not a simple matter of "eating grilled meat once is dangerous." While animal experiments have shown a relationship between PAHs and cancer, the impact on human diets is still not conclusively determined. Diets are complex, involving ingredients, cooking methods, frequency, quantity, constitution, and lifestyle, making it difficult to assert health impacts based on a single food or cooking method.

Nonetheless, invisible risks should not be underestimated. Rather than "completely avoiding," a more realistic approach is to "know the conditions under which they are likely to occur and avoid unnecessarily increasing them."

The Rapid Testing Method "QuEChERS" Highlighted by the Research Team

Measuring PAHs in food is not easy. Traditional tests have used methods such as solid-phase extraction, liquid-liquid extraction, and accelerated solvent extraction, which can be complex, time-consuming, and require large amounts of chemical solvents. This not only burdens laboratories but also poses efficiency challenges for routine food monitoring.

The research team focused on a pretreatment method called QuEChERS. The name stands for "Quick, Easy, Cheap, Effective, Rugged, and Safe," aiming for a method that is literally quick, simple, low-cost, effective, robust, and safe. Originally widely used for pesticide residue analysis, it has recently been applied to analyze various contaminants in food.

In this study, the measurement performance in food matrices was verified for eight types of PAHs: benzo[a]anthracene, chrysene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene, indeno[1,2,3-cd]pyrene, dibenzo[a,h]anthracene, and benzo[g,h,i]perylene.

The analysis involved extracting PAHs from food using acetonitrile, followed by comparing purification methods using combinations of multiple adsorbents. Ultimately, gas chromatography-mass spectrometry (GC-MS) was used for measurement. High linearity was confirmed for all eight PAHs, demonstrating performance capable of detecting trace levels.

The detection limits ranged from 0.006 to 0.035 micrograms per kilogram, and the quantification limits ranged from 0.019 to 0.133 micrograms per kilogram. The recovery rates were generally favorable, showing promising results in terms of both accuracy and practicality required for food safety testing.

Higher Values Found in Soybean Oil, Duck Meat, and Canola Oil

Among the foods examined in the study, soybean oil had the highest concentration of PAHs, followed by duck meat and canola oil. It is important not to misconstrue this as a simplistic conclusion that "soybean oil and canola oil are dangerous foods."

PAH concentrations are influenced by various factors, including not only the raw materials themselves but also processing, drying, heating, refining, storage, and environmental contamination. In the case of vegetable oils, the drying process of raw crops, heat treatment during manufacturing, and environmental contaminants may play a role. For meats, factors such as fat content, cooking method, degree of doneness, and exposure time to smoke are influential.

Thus, the value of this study lies not in "demonizing specific foods," but in demonstrating the need for testing methods that can accommodate a wide range of food matrices, as contamination pathways differ for each food. In food safety management, monitoring based on actual data rather than assumptions is essential.

Reactions Spreading on Social Media: "What Should I Eat Now?" vs. "Let's Think Calmly"

When this news was shared on social media, reactions were largely divided into two categories.

One was voices of anxiety and surprise.
"Is grilling and frying not okay?"
"Even if I cook carefully for health, does the cooking method pose a risk?"
"I love the charred taste, but this might be another story that reduces the joy of eating."
Such reactions are common in news about food risks. The term "carcinogenic" has a strong impact, and anxiety can quickly spread just from reading the article title.

The other was voices trying to take a calm approach.
On forums and nutrition-related communities, there have long been opinions about charred meat and smoked foods, such as "frequency and quantity matter," "it's not a matter of danger from eating once," and "it's important to avoid charring, avoid direct flame, and consider the overall balance of meals." Users knowledgeable in food science often comment, "Nothing is completely safe, and nothing is completely toxic. What's important is the level of exposure and the overall diet."

Meanwhile, there are also reactions with a touch of irony.
"If air, water, and the sun all have risks, what should we do in the end?"
"If we worry about charred steak, there will be nothing left to eat."
Such reactions tend to occur when health news touches on everyday pleasures. Scientific warnings can be perceived by consumers as "restrictions on the enjoyment of food."

Therefore, the way this news is conveyed becomes crucial. PAHs should not be ignored, but excessive fear alone does not lead to practical actions. What is needed is not to make extreme judgments about what to avoid, but to know the conditions under which risks are likely to increase and make small adjustments to daily cooking.

"Not Whether It's Dangerous or Safe, but How Much and How to Eat"

In discussions about food risks, it often becomes a binary choice of "is this okay to eat or not?" However, the issue of PAHs cannot be explained by a binary choice. What matters is which foods are consumed, how frequently, and how they are cooked.

For example, the expected exposure level differs between someone who eats large quantities of heavily charred meat or smoked foods daily and someone who occasionally enjoys a barbecue. Cooking at high temperatures for extended periods and cooking methods like steaming, boiling, or low-temperature cooking can change the amount of compounds generated. Whether one eats the charred parts or removes them also makes a difference.

The U.S. National Cancer Institute states that while HCAs and PAHs generated by high-temperature cooking have shown carcinogenicity in animal experiments, a clear causal relationship with human consumption of cooked meats has not been established. However, they introduce ways to reduce exposure, such as avoiding prolonged exposure to direct flame or high temperatures, frequently turning the meat, removing charred parts, and limiting gravy made from meat juices.

This approach is realistic for consumers.
"Don't stop eating grilled meat entirely," but "don't over-char it."
"Don't avoid fried foods for life," but "consider the frequency."
"Don't demonize smoked foods," but "don't consume them as a daily staple."
Such small choices can lead to food risk management that is not swayed by excessive anxiety.

The Implications for Food Manufacturers and Regulatory Authorities

This study holds significant implications not only for home kitchens but also for the food industry. It is difficult to reduce PAHs without identifying where they increase during manufacturing or processing. If a simple and highly accurate testing method becomes widespread, food manufacturers can more precisely examine raw materials, heating conditions, drying processes, oil management, and smoking conditions.

Furthermore, improving testing efficiency can lead to cost reductions. If pretreatment is simpler, less solvent is used, and work time is shortened compared to traditional methods, it will be easier to continuously monitor more food samples. This relates not only to consumer safety but also to the working environment of researchers and technicians involved in testing, as well as the reduction of chemical waste.

Progress in food safety is not easily noticeable. Unlike new treatments or dramatic discoveries, it rarely becomes a major topic, but in reality, improvements in testing technology are what support daily food safety. As the ability to detect dangerous substances increases, businesses and governments can take measures more quickly.

Practical Measures You Can Take at Home

There are things consumers can do starting today.

First, avoid exposing meat to direct flame for extended periods. In cooking where fat drips and smoke rises, PAHs may easily adhere to the surface of the food. When using charcoal or a grill, even ensuring that flames do not continuously hit the food can make a difference.

Next, avoid forcing yourself to eat charred parts. Beyond enjoying the savoriness, it's safer to remove parts that have turned black and carbonized. Turning the meat frequently, using a microwave for pre-cooking to shorten high-temperature cooking time, and using cooking utensils that prevent fat from dripping onto the fire can also be helpful.

Additionally, diversifying cooking methods is important. Not only grilling, frying, and smoking but also boiling, steaming, low-temperature cooking, and baking without over-charring in the oven can help avoid biased exposure to specific compounds.

And, balance the overall diet. Incorporating vegetables, legumes, seaweed, fruits, and whole grains, in addition to meat and fried foods, and ensuring dietary fiber and various nutrients is fundamental to risk reduction. It's important to manage food risks not based on single components but as part of the overall diet.

How to Read Scientific News

In news like this, the inclusion of the word "carcinogenic" in the headline can easily induce strong anxiety. However, scientifically, what is important is not just the presence or absence of danger, but the actual exposure level, intake frequency, research subjects, detection methods, and the strength of evidence in humans.

The fact that carcinogenicity is shown in animal experiments does not mean that humans bear the same risk in a normal diet. Conversely, the lack of a clearly established causal relationship in humans does not mean that measures are unnecessary. In the world of food safety, it is necessary to think about reducing risks as much as possible while dealing with uncertainty.

On social media, this gradient is often lost.
"Don't eat it, it's dangerous," or "Don't worry, it's not a problem."
Between these two extremes lies the proper scientific way of reading.

What this study has shown is that the technology to measure invisible chemicals lurking in everyday foods more quickly and accurately is advancing. This research is not meant to scare us about our meals. Rather, it is research to manage food safety more precisely and advance necessary measures realistically.

Towards an Era of Balancing Taste and Safety

Browning, smoke, and savoriness are part of the flavors humans have long loved. Yakitori, yakiniku, steak, smoked fish, fried chicken, and French fries. Eliminating all of these from life is not realistic for many people and would unnecessarily deprive them of the joy of eating.

However, enjoying and remaining unaware of risks are different.
Don't over-char.
Don't expose to too much smoke.
Don't rely too heavily on the same cooking method.
Take an interest in advances in testing technology.
Pay attention to the monitoring systems of food manufacturers and governments.

Through these accumulations, food can be enjoyed more safely and wisely.

This study is not commanding us "not to eat anything."
It teaches us that "the ability to measure the invisible supports the safety of the dining table."
And at the same time, by understanding the chemical reactions behind the savoriness, we can slightly update our eating habits.

Not to be afraid, but to choose wisely.
The science of food safety is advancing right next to our dining tables today.

Source URL

ScienceDaily: Referencing research content from Seoul National University of Science and Technology, PAHs, QuEChERS method, and detection results overview.
https://www.sciencedaily.com/releases/2026/05/260522030853.htm
Reference citation:

Seoul National University of Science and Technology research information page: Referencing the summary of the original paper, target PAHs, detection limits, quantification limits, recovery rates, and relatively high values in soybean oil, duck meat, and canola oil.
https://pure.seoultech.ac.kr/en/publications/quechers-method-development-for-the-gcms-analysis-of-polycyclic-a/

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

U.S. National Cancer Institute: Referencing conditions for the formation of HCAs and PAHs in high-temperature cooked meats, uncertainty in human risk assessment, and cooking tips to reduce exposure.
https://www.cancer.gov/about-cancer/causes-prevention/risk/diet/cooked-meats-fact-sheet
##