The Centre for Food Safety (CFS) of the Food and Environmental Hygiene Department released the third report under the Second Hong Kong Total Diet Study (2nd HKTDS) today (December 5). This report is the CFS's first assessment of the overall dietary exposure to perchlorate in food among the Hong Kong population. The findings showed that the estimated dietary exposures to perchlorate for the overall adult and younger populations in Hong Kong remain well below the health-based guidance values established by the international organisation/authority and do not pose a health risk.

     Perchlorate occurs naturally in the environment and is also an environmental contaminant arising from human activities. Perchlorate has been reported to occur in a wide range of foods including vegetables, fruits, milk and dairy products. Perchlorate has low acute oral toxicity in laboratory animals, and the International Agency for Research on Cancer has not classified perchlorate as a carcinogen. Exposure to excessive perchlorate can interfere with thyroid function by reducing the uptake of iodide by the thyroid gland, leading to hypothyroidism. The CFS selected perchlorate as one of the testing parameters in the 2nd HKTDS to assess the local situation and evaluate the dietary exposure to perchlorate of the Hong Kong population in light of the attention that perchlorate has received abroad in earlier years. 

     Out of a total of 187 food items tested in the Study, 144 (77 per cent) were found to contain perchlorate. Among these food items, pumpkin exhibited the highest mean concentration of perchlorate, followed by Chinese amaranth and Chinese parsley. By combining the aforesaid findings with the food consumption data of people in Hong Kong, the estimated dietary exposures to perchlorate for average and high consumers of the adult and younger population were all below 5 per cent of the Provisional Maximum Tolerable Daily Intake of 10 micrograms/kilogram body weight allocated by the Joint Food and Agriculture Organisation of the United Nations/World Health Organisation Expert Committee on Food Additives for perchlorate.

     A spokesman for the CFS said, "The public is encouraged to maintain a balanced and varied diet to support overall health and reduce the risk of exposure to contaminants, including perchlorate, from a limited range of food."

     The 2nd HKTDS aims to estimate the latest dietary exposure of the Hong Kong population and various population subgroups to some chemical substances of potential food safety concern and assess the associated health risks. The public can download the relevant study reports released thus far from the CFS webpage at www.cfs.gov.hk/english/programme/programme_firm/programme_tds_2nd_HKTDS_report.html.

Ends/Friday, December 5, 2025
Issued at HKT 11:55

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