The article goes on to claim that this is not the first time this sort of thing has happened.
It is the latest incident in which fast-food chain employees have been caught out on film after teenage girls working at a KFC in the US were punished after taking a bath in the mammoth kitchen sink - and a male Hungry Jack's worker was sacked for the same offence.
I also have anecdotal evidence of this sort of thing. My aunt told me that, if someone hasn't finished his meal, some restaurants collect the leftovers from the guy's plate and serve the leftovers to someone else. Other person I know works in a sausage factory. He told me that he has seen sausages being dropped on the floor and then picked up again and put on the conveyor belt.
The problem is that there is an incentive for food suppliers to use contaminated food because throwing the food out is wasteful and not profitable. People who eat at restaurants, however, cannot see how the food is prepared.
One way to fix this problem is perhaps to grow your own raw ingredients and then bring them to a chef to make food. Then you watch the chef make the food with your own eyes. Another way to fix the problem is to simply grow as much food as you can from your own backyard and simply eat that.