Major sushi restaurant chain operator Kura Sushi Inc. said Thursday it has installed camera systems equipped with artificial intelligence on conveyor belts at its restaurants, after the industry was shaken by a series of incidents involving customers licking soy sauce bottles and conducting other unhygienic acts.

The major scandal has impacted on the sector, as some of the cases were recorded and posted online, racking up millions of views and prompting some restaurants to file damage reports to the police.

Kura Sushi, which already had cameras installed at its restaurants for counting customers' plates, has modified its system so that it can identify suspicious behavior, such as returning a plate to the conveyor belt.

A camera (top R) as part of an artificial intelligence-equipped system is seen installed on a conveyer belt at Kura Sushi Inc.'s restaurant in Osaka, western Japan, on March 2, 2023. (Kyodo) 

Its offices in Saitama Prefecture, near Tokyo, and Osaka will be notified once the system detects such behavior, and the restaurant in which the incident occurs will be informed. The new equipment can identify the specific plate and seat number in question, it said.

"Conveyor belt sushi is something we are proud of as part of Japanese culture. We want to make sure our customers can eat sushi delivered on the belt safely and comfortably," a company official said.

Other sushi restaurants have also started to take precautions in the face of a sudden surge in malicious customers.

Sushiro, another conveyor belt sushi chain, said last month it will temporarily limit the use of conveyor belts to ordered food.

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