This just in: raw tuna is going to be off the menus of most sushi joints in Shanghai next year, and presumably (I would hope!) the rest of China.

To remain fresh, the deep-water tuna must be stored at -55 Celsius to remain fresh for the consumer. Once it is not, tuna changes in color from a deep red color to a brownish shade. Given that such low temperatures are not possible in China, tuna is often treated with carbon monoxide. This is potentially quite damaging for the consumer's health, particularly the kidneys.

The report quoted a local tuna expert, Professor Wu Jiale of the Shanghai Fisheries University, as saying on last Thursday that a study group he heads has finished drafting an industry standard for tuna eaten raw as Sashimi. The draft, now submitted to the Ministry of Agriculture, is expected to go into effect next year.

It may affect nearly all the restaurants and supermarkets in Shanghai offering tuna Sashimi, industry insiders worried, because most of the tuna on the local market is treated in this way.