Hong Kong’s Consumer Council has uncovered alarming levels of plasticisers and a carcinogenic compound in several widely-used sesame oil, sesame powder, and sesame paste products, prompting urgent health warnings for local consumers. The watchdog’s latest Choice magazine report (Issue 566) analysed 35 common sesame product samples, finding that 27 contained various contaminants. Three sesame oils and one sesame powder exceeded Hong Kong’s action limits for plasticisers by up to 79 times, while one oil contained a potentially cancer-causing substance at levels surpassing EU safety standards.
The Scope of the Investigation
Between November and December 2022, the Council purchased 35 pre-packaged sesame products from supermarkets and department stores across Hong Kong. The samples comprised 20 sesame oils, 10 sesame powders, and 5 sesame pastes. All were tested for chemical contaminants, microbial safety, and nutritional content.
Plasticiser Contamination: A Troubling Discovery
Plasticisers, or phthalates, are chemicals used to make plastics more flexible, but long-term exposure has been linked to reproductive system damage in laboratory animals, as well as potential harm to the liver and kidneys.
The test detected the plasticiser DBP in three sesame oils, two sesame powders, and one sesame paste. Alarmingly, Koon Yat Wah Kee Sesame Oil (Mixed) recorded 24 mg per kilogram—79 times above the Centre for Food Safety’s action level. Tung Chun Small Grind Sesame Oil followed with 5.3 mg/kg, while Dot Dot Green 100% Pure Black Sesame Powder contained 0.8 mg/kg.
Another plasticiser, DEHP, was found in 16 oils, three powders, and one paste. Once again, Koon Yat Wah Kee led the list with 71 mg/kg—exceeding safety limits by 46 times. Amoy Pure Aromatic Black Sesame Oil came next at 3.6 mg/kg.
Carcinogen Alert: Amoy Oil Exceeds EU Limit
Perhaps the most concerning finding was the detection of glycidol, a genotoxic carcinogen, in 13 sesame oils. The worst offender was Amoy Pure Aromatic Black Sesame Oil, which recorded 2,100 micrograms per kilogram—1.1 times higher than the EU standard of 1,000 mcg/kg.
Authorities stress that glycidol can form during the refining process of vegetable oils, and prolonged intake raises the risk of genetic damage and cancer development.
The Five-Star Performers
Despite the troubling results, seven sesame oils earned the Council’s top five-star rating. These include:
- CRUDIGNO Organic Cold Pressed Sesame Seed Oil
- Zi Chu Cold Pressed Sesame Oil
- Bio Planete Organic Virgin Cold Pressed Sesame Oil
- Topvalu Bestprice Japanese Pure Sesame Oil
- Kuki Pure Black Sesame Oil
- Yamada Seiyu Ichibanshibori Black Sesame Oil
- CARWARI Organic Extra Virgin Sesame Oil
Three oils received 4.5 stars: Nisshin Oillio Kaori Hikitatsu Sesame Oil, Lee Kum Kee Pure Stone Ground Sesame Oil (No Added), and M&S Food Rich and Aromatic Toasted Sesame Oil.
Among sesame powders, seven products achieved five-star status, including Shang Lin Xiao Wu, Ma Yuk Shan, Yue Hwa Chinese Products, Health Times, Kobebussan, Lang Zhu Lin, and Xiang Wei. Only Mei Mei Zhan 100% Pure Black Sesame Powder scored 4.5 stars.
For sesame pastes, three items earned five stars: Zhi Ma Wu Black Sesame Paste, macro Certified Organic Unhulled Tahini, and Duo Duo Black Sesame Paste. Carley’s Organic Raw Black Sesame Tahini received 4.5 stars.
Official Assessment: Low Risk Under Normal Consumption
The Centre for Food Safety has stepped in to assess the situation. Officials note that the Codex Alimentarius Commission has yet to establish international standards for plasticisers or glycidol in food. More importantly, they emphasise that sesame oil is typically used in small quantities as a flavouring agent.
For context, even the most contaminated sesame oil sample (50 ml bottle) would require a consumer to ingest over 15.7 grams daily—equivalent to more than a quarter of the bottle—for an extended period to pose a genuine health risk. Since the average high consumer uses only about 3.7 grams per day, and a typical instant noodle seasoning packet contains only 1.4 grams, the risk under normal dietary habits is considered negligible.
Between 2020 and November 2023, the Centre tested approximately 160 sesame product samples for a wide range of chemicals and pathogens, all of which passed safety checks.
What This Means for Consumers
The findings serve as a critical reminder to read nutritional labels carefully and make informed choices. While authorities maintain that occasional use of these products poses little danger, those who consume sesame products daily—especially in larger quantities—may wish to switch to the five-star rated alternatives.
“The most important step is to maintain a balanced diet,” a Council spokesperson advised. “Variety and moderation remain the cornerstones of food safety.”
For concerned shoppers, the full list of test results and product ratings is available through the Consumer Council’s Choice Magazine (Issue 566). As new shipments enter the market, manufacturers have been urged to review their production processes to eliminate contamination at the source.