Polystyrene is one of the most commonly used plastics - mainly as protective packaging. It is based on monomer styrene, which is hazardous to health. Polystyrene is regularly used in the food industry as packaging for chocolates, salads, or margarine. It is useful for producers of packaging as well as food to know the amounts of styrene that leak from the packaging. A significant amount of the styrene monomer can accumulate in food products when exposed to higher temperatures, e.g. in summer or after interruption of the cold chain.