Abstract

  1. The Food and Environmental Hygiene Department (FEHD) and the Consumer Council conducted a joint study on table salt and cooking salt with an aim to assess the safety of salt available in Hong Kong. There are recent public concerns on the possibility of abuse of industrial salt as food-grade salt. Since salt is commonly considered as a vehicle for iodine fortification for the general population, this study also examined the level of iodine in salt in Hong Kong.
  2. A total of 74 salt samples, including 59 prepackaged and 15 non-prepackaged ones, were collected from different retail outlets and grocery stores throughout the territory in September 2004. The samples were sent to the Food Research Laboratory of FEHD for analysis of the levels of five metallic contaminants (namely, arsenic, cadmium, copper, lead and mercury), sodium chloride content and iodine content. The results were compared with "Codex Standard on Food Grade Salt".
  3. All the salt samples were not detected with the five metallic contaminants. This suggested that there is no evidence of abuse of industrial salt as food-grade salt in Hong Kong. As for the sodium chloride content, Codex has set a compositional and quality factor for food-grade salt. Of the 74 samples, 64 (86%) were found to meet this composition and quality factor of at least 97% sodium chloride. For the 10 prepackaged salt samples that contained less than 97% of sodium chloride, they were found to contain other minerals such as sulphates which are of little toxicity implication.
  4. Concerning iodine fortification, three products were found labelled as iodised salt and the level of iodine detected in these samples were 31, 36 and 43 mg/kg respectively. One prepackaged sample without labelling iodisation was found to contain very low level of iodine at 1.7 mg/kg which may be naturally occurring. Pregnant and lactating women who are more prone to suffer from iodine deficiency could eat iodine-rich foods. If indicated, they could also choose iodised salt as an alternative dietary source of iodine. However, they should seek advice from health professionals beforehand. The trade is also advised to label iodised salt products properly so as to let consumers make informed choices.

April 2005

For the study report (only available in Chinese), please click the following website:
"Study on Salt in Local Market (Chinese version)"