The allegations come at a difficult time for the BBC.
In October, the BBC announced details of a review into preventing abuses of power, in the wake of revelations about Huw Edwards, formerly its most senior news presenter, who committed offences involving child abuse images.
In November, BBC Chair Samir Shah said in a speech that there “continues to be a sense that powerful people ‘get away with it’.”
One MasterChef worker we spoke to, who we’re calling Claire, thinks that how the industry responds to allegations is at the root of the problem.
“We should be getting better at dealing with this, we should be getting better at shutting things down, and not allowing celebrity or fame or power to embolden people to think they can act like that, and treat people really poorly.”
Announcing its investigation on Thursday, Banijay UK, which produces MasterChef, said in a statement: “This week the BBC received complaints from individuals in relation to historical allegations of misconduct while working with presenter Gregg Wallace on one of our shows.”
Wallace, 60, is “committed to fully co-operating throughout the process”, it added.
Banijay’s statement concluded by encouraging anyone who wanted to raise any issues or concerns to come forward.
A BBC spokesman said: “We take any issues that are raised with us seriously and we have robust processes in place to deal with them.”
A spokesman for Channel 5, which airs Big Weekends, said: “We take any allegations of this nature extremely seriously.
“We have asked the production company to look into these historical claims. The health and wellbeing of everyone involved in our productions is very important to us and we want all of our productions to be safe and secure places for people to work.”
Production company Rumpus, which produces Big Weekends, said: “We do not tolerate inappropriate behaviour on our productions.
“Our comprehensive duty of care processes were in place during production of these series and any matters raised would have been investigated in accordance with these.”