Chinese consumers are used to food safety scandals, from toxic heavy metals in their rice to cooking oil scraped up from the gutter. After those outrages, they might be grateful for some good old-fashioned painkillers in their soup.

The website of Xinhua, the Chinese government's official information agency, reported Thursday that restaurants around the country are routinely spiking their dishes with poppy shells, which contain opiates like morphine and codeine, to keep customers coming back.

Hotpot, noodles and lobsters are the most common dishes to get this treatment, Xinhua said. The tactic isn’t new – 215 restaurants in Guizhou province were shut down for spiking their food with opiates way back in 2004 – but has been receiving increasing media coverage as multiple incidents have come to light.

Last month a noodle shop owner in Shaanxi province admitted dosing his dishes with poppy buds after a customer tested positive on a drug test, according to a local paper (in Chinese). A clutch of Shanghai restaurants were reportedly busted for the same thing last December (in Chinese).

The punishments for these infractions are surprisingly light, in a country not known for its lenient treatment of criminals. The boss of one lobster joint in Shanghai got off with a year in prison and a 10,000 yuan ($1,636) fine, Xinhua said.

The opiate content of these dishes isn't enough to generate much of a high, according to a doctor interviewed by Xinhua, but regular use could still get you hooked – not to mention failing a drug test.

Though illegal to trade, poppy shells -- which are left over after the edible seeds have been taken out -- aren't difficult to get hold of, Xinhua said. Their reporter found the buds on sale in Sichuan at 200 yuan for half a kilo, and for similar prices online.

One food safety inspector in Sichuan told Xinhua that tracking down perpetrators is tricky. Hotpot restaurants are getting wise to inspectors who test the bubbling cauldrons of broth where they used to add a dose of poppy shell; now they powder it up and add it to chili oil or MSG – widely used in Chinese cooking – where it is almost impossible to detect outside a lab.

-- Richard Silk. Follow him on Twitter @richardjsilk

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