A part-time worker at a Pizza Hut outlet in Tokyo uploaded a photo of himself on Twitter with pizza dough plastered all over his face in May, Kentucky Fried Chicken Japan Ltd., which owns the pizza delivery chain, has revealed.

The company apologized Monday, saying such behavior as totally unacceptable in the food-handling business. It also said it may discipline the employee, a male college student who no longer works at the pizza chain.

"We apologize to our customers, to whom this incident might have caused any inconvenience or anxiety," KFC Japan said.

According to the firm, the part-timer, who worked at Pizza Hut's Takaido delivery outlet in Suginami Ward, uploaded a picture while on duty Sunday showing his face covered with dough. The student reportedly revealed to his supervisors the picture had been taken after he finished work on May 9.

"I did it out of carelessness," he was quoted as saying by his employer.

According to KFC Japan, the dough, which wasn't made into a pizza and thus expired on the day it was rolled, would not have been used for any customer order.

Similar antics involving workers in the food industry have also occurred at outlets of the convenience store franchise chains Lawson Inc. and Ministop Co. In both cases, part-timers were fired after they uploaded photo onto the Internet showing themselves inside ice cream freezers at the stores where they had worked.

A similar prank at a Bronco Billy's Steakhouse outlet not only led the owner to close the eatery but also prompted the chain's owner, Bronco Billy Co., to sue the former workers for damages.