TOKYO (AP) — Japanese police have arrested two men who posted a clip in which one of them is eating ginger from a communal container with his chopsticks at a famous beef bowl restaurant, part of a series of pranks that had hit sushi chains and became known as “sushi terrorism.”

Osaka prefectural police on Wednesday said Ryu Shimazu and Toshihide Oka were arrested on suspicion of obstructing business as well as destroying and dirtying property.

In a video filmed by Oka and shared on social media, Shimazu is seen repeatedly shoveling shredded pickled red ginger — staple topping for the beef bowl — into his mouth with his chopsticks, instead of a thong that customers are supposed to use, police said.

Shimazu told police that he wanted to make people laugh. Oka said he was the one who encouraged Shimazu to do something funny, and he shared the video because it was funny and he wanted people to see it, police said, adding that the duo had nothing against the restaurant.

Police arrested Shimazu, 35, in March, and Oka, 34, this week, officials said, and both admitted the charges against them. If convicted of obstructing business, they could face fines of up to 500,000 yen ($3,800) or up to three years in prison, and for property destruction, up to three-year prison term or a fine of up to 300,000 yen ($2,280).

Their prank surfaced only in February when a customer notified the chain about the video they saw, prompting the restaurant to temporarily close to discard all ginger condiment and clean its containers, police said. Yoshinoya also reported to police.

Police identified the restaurant only as part of the Yoshinoya chain, in the Suminoe district of Osaka.

Yoshinoya Holdings said it was regrettable that the news of the prank caused discomfort for many customers while raising questions over safety of the entire food industry, and that the company hoped similar problems won’t be repeated, Kyodo News reported.

The reasonably priced gyudon, a bowl of rice topped with soy-flavored beef and onion, is a popular meal, and the incident at Yoshinoya, which operates more than 1,100 outlets nationwide, apparently caused some concern, coming just weeks after a series of pranks at revolving sushi chains that became known as “sushi terrorism.”

In one case, police in February arrested three for allegedly obstructing business by licking the top of a communal soy sauce bottle, grabbing passing sushi with bare hands and eating it at a major “revolving” sushi restaurant in central Japan.

Other sushi chains were also hit by similar pranks and have taken action, including installing surveillance cameras to monitor customers or even halting their sushi serving conveyors.