Seaweed with arsenic levels 22 times the safe consumable standard has been stopped at the Australian border averting potential fatalities in children.
In Australia, arsenic levels are regulated by Food Standards Australia New Zealand, which permits a maximum of one milligram per kilogram. In September, the Japanese product was stopped on the way to supermarket shelves after it was assessed to have 22 milligrams of inorganic arsenic per kilogram.
A spokeswoman from FSANZ said the risk to a child would depend on how much was eaten and how much the child weighed.
''However, as a figure of 22 milligrams of inorganic arsenic per kilogram of seaweed is well above the maximum level permitted under the code, this product is not suitable for consumption,'' the spokeswoman said.
But in an article by the director of the Clinical Toxicology Consult Service at the University of Utah's Health Sciences Centre, Martin Caravati, wrote that the acute minimum lethal dose of inorganic arsenic per day was 70 milligrams to 200 milligrams per kilogram.
''Less than one milligram per kilogram of inorganic arsenic can cause serious illness in children,'' Dr Caravati said.
The same type of seaweed, Mehijiki dried seaweed, was rejected in November 2012 with inorganic arsenic levels in excess of 65 milligrams per kilogram detected.
The Australian Quarantine and Inspection Service rejected more than 260 shipments of food this year, up to September 30, for failing to meet chemical and bacterial standards, including three shipments of cooked prawns from China and Thailand blocked because of the presence of cholera bacteria. About 5 per cent of imported foods are tested on arrival in random surveillance, but high-risk foods such as cheese and seafood are tested more often.
Australian National University public health and infection expert Martyn Kirk said the impact on people would depend on the amount of the bacteria or chemical consumed.
''The random testing is needle-in-a-haystack stuff so it's probably going to miss a lot. But we do have a good surveillance program for infectious diseases that cause human illness,'' Dr Kirk said.
''It does pick up those foods that we have identified as high risk.''