The operator of one of Japan's largest sushi restaurant chains said Wednesday that video footage recently uploaded to the internet showed one of its part-time kitchen workers throwing sliced fish into a trash can and then returning it to a cutting board at an outlet in Osaka Prefecture.

Kura Corp., which operates some 400 Kura Sushi restaurants in Japan, said that the fish was disposed of and never served to customers, but that it takes the incident seriously and is considering legal action, without elaborating.

In the footage, the male worker picks a slice of fish from a cutting board and throws it into the trash receptacle filled with plastic bags and styrofoam trays, reaches into the garbage to retrieve the fish and places it back on the cutting board. The worker uploaded the video online and it has since gone viral.

The company said the video was taken at its outlet in Moriguchi.

"We deeply apologize for causing disgust and unease to our customers because of this footage," Kura said in a statement, adding it will make utmost efforts to train its employees so such behavior is not repeated.