Results of study on dietary exposure to chloropropanols

The Centre for Food Safety (CFS) today (July 17) released results of a study on dietary exposure to chloropropanols and its assessment of associated health risks.

The Centre's Consultant (Community Medicine) (Risk Assessment and Communication), Dr Ho Yuk-yin, said 318 food samples were taken to test for two types of chloropropanols: 3-monochloropropan-1,2-diol (3-MCPD) and 1,3-dichloro-2-propanol (1,3-DCP).

The samples covered eight major food groups: cereals and cereal products; vegetables and their products; fruit; fish, shellfish and their products; meat, poultry and their products; eggs and their products; dairy products; and snacks.

The results showed that 3-MCPD in most of the food samples, including vegetables, fruits, eggs and dairy products, was below the limit of detection (LOD) (2.5 μg/kg). Among others, ready-to-eat seaweed had the highest concentration of 3-MCPD (average: 56 μg/kg).

"Chloropropanols can be present in foods for various reasons. Condiments such as soya sauce and oyster sauce, after going through an acid treatment, would contain 3-MCPD," Dr Ho said.

"Other food products, such as instant noodles and hamburgers, that used acid-hydrolysed vegetable protein as an ingredient, also contained 3-MCPD. Lipids and sodium chloride in foods also contribute to the formation of 3-MCPD during normal heat processing such as coffee roasting and bread baking."

"The presence of 3-MCPD in some foods might also be due to the use of certain types of sausage casings, tea bags and coffee filter paper."

The study also found that 1,3-DCP in most food samples was below the LOD (0.5 μg/kg). Only fish, shellfish and their products; meat; poultry and poultry products were detected with 1,3-DCP. Roast pork had the highest average level (9.3 μg/kg).

However, it is still not known how 1,3-DCP is produced in foods.

According to the Joint Food and Agriculture Organisation of the United Nations/World Health Organisation Expert Committee on Food Additives (JECFA), 3-MCPD is generally not genotoxic to humans. However, the genotoxicity of 1,3-DCP cannot be ruled out.

Dr Ho said that to assess the associated health risks based on the current study, the CFS used the food consumption data from an earlier survey conducted among about 1,000 local secondary school students.

"It showed that the daily dietary exposure to 3-MCPD for an average secondary school student falls well below the provisional maximum tolerable daily intake of 2 μg/kg bw/day established by JECFA. It was also found that cereal and cereal products, particularly instant noodles were the largest contributor to total dietary exposure to 3-MCPD (average: 0.012 μg/kg bw/day).

"As for 1,3-DCP, the margin of exposure for an average secondary school student is of low health concern. And sausage was also found to be the largest contributor to total dietary exposure to 1,3-DCP (average: 0.002 μg/kg bw/day).

"Based on these assessments, chloropropanols exposure through normal food consumption should not pose any adverse health effects," he said.

Dr Ho appealed to the food trade to observe good manufacturing practices to reduce the levels of chloropropanols in food as far as technically achievable. Members of the public are also advised to maintain a balanced diet.

Ends/Tuesday, July 17, 2007