A school that was reprimanded last year for serving students expired food has wound up in the spotlight again after using supplementary material for eighth-graders that contained a sexual joke.

The education authority of Pudong New Area in Shanghai has ordered severe punishment for those responsible for the teaching materials used by SMIC Private School (Shanghai), and called for an overhaul of supplementary textbooks at primary and middle schools in the region.

The education bureau told the school to immediately stop using the materials, the authority said in a circular on Thursday. It also accused the school of chaotic management and misdeeds in the selection of supplementary materials.

The reprimand was for including material in a book for youngsters that referred to female anatomy and strongly alluded to an oral sex act. It was published by Shanghai Oriental Laser Education Culture.

Parents of the eighth-graders discovered the off-color joke, titled "Mommy's Washcloth", in a book assigned as homework for winter vacation.

Children had been asked to read the joke and leave their comments.

The school, founded in 2001 by Semiconductor Manufacturing International (Shanghai) Corp, has more than 2,900 students from 25 countries and regions. It admitted its fault on Thursday in selecting the material.

In October, the school was caught up in a food safety scandal after parents found expired goods, moldy produce and unhygienic conditions during a surprise inspection of its kitchen. That incident led to a call for stronger inspections of school canteens.

The school will be severely punished for the sexually oriented joke, according to the education authority.

Xiong Bingqi, deputy dean of the 21st Century Education Research Institute, said on Thursday that both the publisher and the school were at fault.

"That the material was able to enter the school's procurement system shows chaotic management. Private schools need to strengthen internal management to prevent such mistakes," Xiong said.

Xiong also suggested that the faculty and parents' association should be involved in the selection of supplementary learning materials at private schools. On one hand, such a move would reflect the autonomy of the school, while on the other hand it would improve the overall quality of the books the school uses, he said.

On Thursday, the school strongly condemned the company and said it had punished the vice-principal and another teacher.