OSAKA — The president of USJ Co., the operator of the Hollywood theme park Universal Studios Japan here, said Thursday he will resign to take responsibility for a series of problems at the park, including its sale of expired food to customers.

“I have decided to step down as president as I feel grave responsibility” for the problems, Akira Sakata, 62, said. He will be replaced by former Deputy Osaka Mayor Shin Sasaki.

Sakata became president of the firm in 1999 after retiring as an Osaka City government official.

He also apologized to visitors to the theme park and shareholders in the firm, the largest of which is the Osaka City government.

Visitor numbers dropped following revelations that USJ had been serving customers old food, that a park water fountain was connected to an industrial water supply and that USJ had stored excessive amounts of explosives for fireworks.

There were 4.29 million visitors to USJ between April and September, down 29 percent from a year earlier.

Sakata also stressed to reporters that he did what he could to carry out his duties over the past three years and five months at USJ.

Last month, the park’s popular Hollywood Magic fireworks attraction, which at one point had been at the center of the park’s woes because it was caught using more explosives than its license called for, was given the go-ahead to reopen.

Sakata called on USJ staff to work together under the new leadership, adding he believes there will be no recurrence of the incidents.

The theme park opened in March 2001.