Two men have been arrested for a prank involving ginger garnish at an Osaka beef bowl restaurant and posting a video of their act on social media.

Police in Osaka Prefecture, western Japan, nabbed Shimazu Ryu and Oka Toshihide, both in their 30s, on suspicion of property damage and forcible obstruction of business at an outlet of Yoshinoya, a major 'gyudon' beef bowl chain, in September last year.

Investigators say Shimazu ate red pickled ginger garnish directly from a common container with his chopsticks. Oka allegedly used his smartphone to video the scene and posted it on social media.

In February this year, the restaurant noticed the video on social media, and temporarily closed the business for disinfection.

Shimazu told investigators that he wanted to make people laugh. Oka reportedly said he asked Shimazu to do something amusing, and that he posted the video because it was so funny.