It’s a little too easy to test positive for opium these days

Liu Juyou probably wasn't thinking of Seinfeld when he was arrested. But we were.

The 26-year-old from the northern Chinese city of Yanan was jailed after failing a random drug test. He said he had never taken an illegal substance in his life. 

Liu suspected the source of the opium found in his body was the bowl of noodles he had consumed a few hours earlier — a reasonable assumption to make in a country where food contamination scandals are common.

To prove his theory, Liu convinced several family members to go to the same restaurant, slurp down a bowl of noodles and submit themselves to a drug test.  

Much to the surprise of the skeptical police officers, Liu’s relatives also tested positive for opiates.  

Police launched an investigation and the owner of the noodle shop fessed up.

He had been secretly lacing his dishes with ground poppy buds, which contain a milky fluid used to make opium, to keep his customers coming back again and again.  

Liu is not the first person to test positive for opium after eating certain food. 

There have been numerous incidents where people have failed a drug tests after eating a poppy seed bagel, muffin or cake.

Poppy seeds, which are found inside the poppy bud, can still have traces of opium even after they have been cleaned and processed for commercial use. 

Eating just one poppy seed muffin can be enough to create a positive reading — as Seinfeld's Elaine Benes found out in this hilarious 1996 episode.

There are plenty of real-life cases where people have lost their jobs — or worse — for failing a drug tests after innocently scoffing down a bagel.  

Elizabeth Mort, for example, had her newborn baby taken from her for five days in April 2010 after opium was found in her system during a routine drug test. Mort blamed the positive result on the poppy seed bagel she ate shortly before giving birth to her daughter in Pennsylvania. She got her baby back. A child welfare agency and the hospital were ordered to pay compensation.

A 2003 study by the German Institute of Biochemistry at the German Sport University Cologne found athletes who consumed products containing commercial poppy seeds could test positive for morphine, a psychoactive chemical in opium.

“Even 48 hours after the oral intake of cake containing poppy seeds, the urinary level of morphine can exceed the (International Olympic Committee) allowed threshold,” the scientists found.

Yikes!