Alistair Macrow, chief executive of McDonald’s UK and Ireland, told MPs that the claims alleging abuse or harassment at work were “truly horrific” and “hard to listen to”.
It comes after workers made a series of sexual abuse, racism and bullying allegations in July following a BBC investigation.
McDonald’s said 18 members of staff had been sacked as a result.
Earlier this month, law firm Leigh Day said a group action had been launched on behalf of a number of employees in relation to assault and harassment allegations.
Yesterday Mr Macrow said 157 reports have been fully investigated, with 75 resulting in disciplinary action, including sackings.
McDonald’s is still looking into 249 other reports relating to safety and inclusivity in the workplace.
There have been 17 confirmed reports of sexual harassment. A further 27 claims are being probed.
Mr Macrow told MPs on Parliament’s Business and Trade Select Committee: “We typically would see 20 and 25 contacts per week, of which one or two are sexual harassment, across the organisation.”
In response to this summer’s claims, McDonald’s launched a programme of independent investigations, audits of its complaints procedure, reviews of its code of conduct and a number of full disciplinary hearings. Mr Macrow added: “To be in charge of the business when these incidents are occurring is very hard to hear.
“I am absolutely determined to root out any of these behaviours, to identify individuals who are responsible for them and make sure they are eradicated from our business.”
He stressed, however, that he does not see abuse and sexual harassment at the business as “an endemic cultural issue”.
Earlier in the session, union bosses told the committee that the situation had not improved for McDonald’s workers since the company launched its investigations.
Ian Hodson, of the Bakers, Food and Allied Workers Union, said: “The feedback we are getting is that nothing has changed. There is a tick-box system that has been put in play…a video about how things are supposed to happen.”
Unions also claimed McDonald’s has a history of using non-disclosure agreements in response to allegations.
Mr Macrow rejected these claims but admitted including “confidentiality clauses” in some cases where workers had left the company after signing a settlement agreement.
