Sesame seeds dyed black are the latest case of painted food
Will Clem in Shanghai
Shanghai shoppers have been warned to watch out for dyed sesame seeds in the latest in a series of food quality scares to hit the mainland.
The seeds are coloured with an unidentified dye that turns water 'as black as ink' when they are washed, the Shanghai Daily reported.
The warning, from the city's food safety watchdog, comes on the heels of a clampdown on oranges that have been dyed with toxic wax.
The Shanghai Industrial and Commercial Administrative Bureau told the paper it had launched an investigation into the source of the seeds.
'This is the first time that we have heard of dyed sesame seeds,' an official told the paper.
The bureau was alerted to the seeds after a customer complained that they continued to turn water black after half a dozen rinses, while some of the seeds turned white.
The customer bought the seeds for 9 yuan (HK$10.50) per 500 grams, less than half the normal market price, the paper reported.
It is not known what the colouring agent is, nor whether it poses any health risk.
There was no one at the bureau available to comment on the situation yesterday.
The crackdown on artificially coloured oranges was launched last week after authorities found some were sprayed with a toxic wax.
As part of the clampdown, food safety authorities confiscated 'hundreds of kilos' of dyed oranges at a wholesale market in Pudong over the weekend, local media reported.
However, brightly coloured oranges with a distinctly unnatural hue remained on sale in some fruit stalls checked by the South China Morning Post.
Occasional patches of the fruit's pale yellow-orange natural colour showed through gaps in the shiny wax finish that appeared to have been sprayed on. 'We haven't noticed any impact on our business,' said one shopkeeper in central Jingan district.
'No one has visited our store to test the oranges and I haven't been aware of any change in wholesale prices or the supply.'
Staff at another store denied their equally garish oranges had been dyed.
'You haven't seen them growing on the trees,' said one saleswoman. 'That is their natural colour. They turn orange like that in the sunshine.'