Hi Jen,
actually I don't know which kind of cockroaches there are in Quennsland.There are different ways to keep out and monitoring cockroaches like Orientalis, Germanica, Periplaneta or Supella (these are the species that living in Italy).Our laws permitted to manage and apply pest control "in-house" in the food factory but only if you are graduate and trained in Pest Management so if you are not I recommend you to call a Pest Control Company and ask a plan to prevent and monitoring cockroaches in the food factory.
First becouse you need to be trained and also becouse you need products, glue traps, pheromones to attract and you have to be very lucky to find out the right products at the first shot.
And cockroaches grows so fast with warm temperature and humid so is not a good idea to risk.
Best regars
Norman Rosi
Quality Manager
Romani Disinfestazioni Srl Lucca Tuscany Italy