Donaldson questioned Mondelez' decision to attend while ''knowing they also have legal good faith obligations to the union and staff to genuinely look at and consider alternatives to closure''.
Reporters from the Otago Daily Times arrived just before it was set to conclude, waiting outside in the reception area of the mayoral lounge.
No-one was keen to talk when they emerged from the 90-minute meeting, including Labour MP Clare Curran, and Dunedin City councillor Aaron Hawkins.
National MP Michael Woodhouse told a reporter to ''drop me a line'' before striding out.
Woodhouse said Cull would address the media about the outcome of the meeting.
Soon after, ODT reporters and a photographer were told to leave by DCC communications director Graham McKerracher.
McKerracher said the area was ''not a public place'', despite the reporters having signed in to the building.
Some attendees, including the Mondelez group, stayed in the mayoral lounge after the meeting.
It is understood Cull cancelled a planned media stand-up with reporters.
The ODT is seeking a response from Mr Cull and Mondelez International.