The local council should be advised, they could send out an ordnance inspector to deal with the owner. The building presumably is in a residential zone, and no doubt the original development approval was for residential use.
As far as the strata scheme is concerned, the coming and going of trucks can be against your by-laws, particularly when it causes obstruction and inconvenience to other residents. Does the owner have one or more cars, if so are they parked on common property instead of in the garage, in contravention of a by-law?
And since food and drink are involved, are these refrigerated in the garage?
Often the power supply to the garages will be on a metered supply which is billed to the owners corporation. Under those circumstances refrigerators and freezers will be costing the owners significant amounts of money. Worth while checking out, you don’t want to be copping the inconvenience of some-one using part of their lot illegally for commercial purposes and having to subsidise their business as well.