A patron of the restaurant started the ball rolling when he found a screw in his kebab meal in early March.
The customer returned the next day to complain, but was surprised to hear that it wasn't the first time a diner had found such an object in their food.
"The screw was part of some tongs that we always use with the salad and it eventually came loose and fell in the kebab tray," the restaurant owner told the Dagens Nyheter (DN) newspaper.
"The screw is black and the kebab is black - it isn't so easy to see it."
But the plot thickened when the customer alerted the local council's environmental office (miljökontoret). Inspectors discovered that the restaurant owners were using a cement mixer that had been painted blue for making salad dressing and sauces.
The owners were unable to explain what had happened with the pieces of paint that had flaked away and fallen off the machine.
"When I took over the restaurant, the previous owner told me that everything had been approved," the owner told DN, adding that he was new to the restaurant business and unaware of the rules.
"When health inspectors pointed out that the cement mixer wasn't acceptable, I threw it out and bought a rust-free mixer the very same day."