Oil is an essential ingredient for cooking. According to the Consumer Council’s recent test on 50 samples of cooking oil, 94% were detected with 1 or more types of harmful contaminants. 29 samples were detected with the genotoxic carcinogen glycidol, 2 of which even exceeded the European Union’s standard.
The Council sourced 50 samples of common varieties of cooking oils from supermarkets and department stores, covering 13 categories, including 14 extra virgin olive oils, 2 olive oils, 2 avocado oils, 3 coconut oils, 2 camellia oils, 2 sunflower oils, 2 rice bran oils, 2 grapeseed oils, 3 corn oils, 6 canola oils, 1 soybean oil, 6 peanut oils and 5 blended oils.
Some types of cooking oils need to undergo high-temperature refinement during the manufacturing process. The toxic 3-MCPD and genotoxic carcinogen glycidol will be released. The watchdog said approximately 60% samples detected with 3-MCPD (30 samples) and glycidol (29 samples) respectively.
One coconut oil (Superfood Lab Coconut Cooking Oil) and one peanut oil (Yu Pin King Pure Peanut Oil) samples were detected with 1,100μg and 2,000μg glycidol respectively, both of which exceeded the maximum level of 1,000μg / kg set out in the EU standard.
The content of the 3-MCPD also varied by more than 13 times between the samples with the lowest (130μg) and highest (1,900μg) levels. The highest 3-MCPD content was found in 1 sample of blended oil, yet it did not exceed the EU standard, and would probably not pose health risks when consumed in regular portions.
Excessive consumption of 3-MCPD over a prolonged period would adversely affect the kidney functions, central nervous system, and male reproductive system of laboratory animals.
The test also found both 3-MCPD and glycidol in 1 sample of extra virgin olive oil and 2 samples of camellia oil which claimed to be cold-pressed. Despite the levels not exceeding the EU standard, it was suspected that the samples may have been treated with high temperature, or had been contaminated with non-cold pressed oils.
Besides, 2 samples were detected with the genotoxic carcinogen benzo (a) pyrene, of which the concentration in 1 sample of corn oil (2.1μg / kg) slightly exceeded the EU standard (2.0μg / kg).
The test also found plasticisers in around 70% of the samples, approximately the same percentage of the 2017 test results.
However, 5 samples in the 2017 test had exceeded the action level of the CFS and the maximum limit of the EU, whereas only 1 sample of extra virgin olive oil in the current test exceeded such limits, showing signs of improvement.
Besides, the test also revealed that 8 samples had a variance between their actual and declared nutrient content that exceeded the stipulated tolerance limit (20%). The most severe case was the polyunsaturated fatty acid (PUFA) content for 1 sample, which had a variance of 85% with the labeled value. The Council urges manufacturers to promptly rectify discrepancies on the product labeling and provide consumers with accurate information.