A salty diet is unhealthy, let alone salt laced with toxic heavy metals.
The concern over the contamination of salt followed recent reports that industrial-grade salt was put on sale for human consumption in the mainland.
In collaboration with the Food and Environmental Hygiene Department, the Consumer Council has released a joint test report to assess the safety level of 74 samples of salt in the local market.
The 74 test samples consisted of 59 prepackaged products with claims of countries of origin from, besides the Mainland, Australia, Britain, France, Italy, Japan, New Zealand, and Spain. The remainder salt samples were sourced in loose pack from 15 different local grocery stores.
There is currently no specific legislation governing the content of salt in Hong Kong but, internationally, the Codex Standard for Food Grade Salt laid down that the seasoning condiment may not contain contaminants in amounts and in such form that may be harmful to the health of the consumer.
The test set out to investigate the presence of such metallic contaminants as arsenic, cadmium, copper, lead and mercury, in the samples.
The analysis, much to the relief of consumers, drew a blank: none of the samples were detected with any of the metallic contaminants in question.
There is also no evidence that industrial-grade salt was being marketed in Hong Kong for human consumption.
In addition to metallic contaminants, the Codex Standard also includes a compositional and quality factor requiring that the content of sodium chloride in food-grade salt shall not be less than 97% on a dry matter basis, exclusive of additives.
According to the test, 64 samples (86%) measured up to the standard on sodium chloride content while nine samples (12%) were found to contain the compound ranging from 90 to 94% and one had only 80%.
Samples with lower sodium chloride content were found to contain other minerals such as sulphates, which are of little toxicity implication.
In the test iodine was found in four prepackaged samples; three were labelled accordingly ranging in iodine content from 31 to 43 mg per kg salt. The one sample without labelling iodisation was detected with a low level of 1.7 mg iodine per kg salt (which may be naturally occurring).
In iodine-deficient areas, food grade salt may be iodized to prevent Iodine-Deficiency Disorders (IDD) for public health reason. In general, iodine deficiency is not serious in Hong Kong.
Those who are more prone to IDD, for example, pregnant or lactating women, could get dietary iodine from iodine rich food such as fish, seaweed and other seafoods. They are advised to seek medical advice before taking iodised salts.
Though the safety level of salt has been satisfactorily ascertained, nonetheless, too much salt intake could induce hypertension and increase the risk of cardiovascular disease. As recommended by the World Health Organization, adults should limit to less than 5 g salt a day.
Low sodium salt substitutes (using mostly potassium to replace sodium) are being marketed for the health conscious. But consumers are advised to seek medical advice when taking these products especially those with kidney diseases and those on hypertension or heart failure drugs.
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