Hong Kong’s Consumer Council has uncovered widespread contamination in sesame products, with 27 out of 35 tested samples containing various pollutants, including plasticizers exceeding safety limits by up to 79 times and one sesame oil sample containing a carcinogen above European Union standards.
The findings, published in the council’s May 2025 issue of Choice magazine (Issue 566), have sent shockwaves through Hong Kong’s culinary community. Sesame oil, sesame powder, and sesame paste—staples in countless kitchens across the city—are now under scrutiny after laboratory tests revealed alarming levels of industrial chemicals and potentially cancer-causing substances in popular brands.
The Scope of the Investigation
Between November and December 2022, the Consumer Council collected 35 commonly available sesame products from supermarkets and department stores. The sample pool included 20 sesame oils, 10 sesame powders, and 5 sesame pastes. What emerged from the testing laboratory was deeply concerning: 27 samples—fully 77 percent of those tested—contained detectable levels of various contaminants.
Plasticizer Contamination: A Chemical Cocktail
The most striking finding involved phthalate plasticizers, industrial chemicals used to soften plastics that can leach into food during processing or packaging. Three sesame oils and one sesame powder sample contained levels of DBP (dibutyl phthalate) exceeding the Centre for Food Safety’s action levels.
Koon Yick Wah Kee Sesame Oil (Blended) registered a staggering 24 milligrams per kilogram of DBP—79 times the safety threshold. Tung Chun Small Grind Sesame Oil contained 5.3 mg/kg, while Green Dot Dot 100% Pure Black Sesame Powder tested at 0.8 mg/kg.
Even more widespread was DEHP contamination, detected in 16 sesame oils, 3 sesame powders, and 1 sesame paste. Koon Yick Wah Kee again topped the list at 71 mg/kg—46 times the action level—while Amoy Pure Black Sesame Oil registered 3.6 mg/kg.
Health experts warn that long-term exposure to these plasticizers has been linked to reproductive system damage in laboratory animals, along with potential harm to the liver and kidneys.
A Carcinogen in the Kitchen
Perhaps most alarming was the discovery of glycidol, a genotoxic carcinogen, in 13 sesame oil samples. Amoy Pure Black Sesame Oil contained 2,100 micrograms per kilogram—1.1 times above the European Union’s safety limit of 1,000 µg/kg. Glycidol forms during the high-temperature refining process of oils and has been classified as probably carcinogenic to humans.
The Silver Lining: Top-Rated Products
Despite these troubling findings, the council identified several products that earned top marks. Seven sesame oils received a perfect 5-star rating, including CRUDIGNO Organic Cold Pressed Sesame Seed Oil, Bio Planete Organic Virgin Cold Pressed Sesame Oil, and Kuki Pure Black Sesame Oil.
Seven sesame powders also achieved 5-star status, including Shanglin Xiaowu Black Sesame Powder, Ma Yu Shan Black Sesame Powder, and Kobebussan Black Sesame Powder. Three sesame pastes earned top ratings: Sesame House Black Sesame Paste, macro Certified Organic Unhulled Tahini, and Dodo Black Sesame Paste.
What Consumers Should Do Now
The Centre for Food Safety has already ordered the suspension of affected batches. For consumers, the council recommends checking product labels carefully and choosing brands that have demonstrated compliance with safety standards. Opting for cold-pressed or organic varieties may reduce exposure to contaminants formed during high-temperature processing.
This investigation serves as a critical reminder that even everyday pantry staples require vigilant oversight. As the council continues its testing programs, consumers are urged to stay informed through Choice magazine and to report any concerns about product quality to relevant authorities.