Abstract: A method for examining food products for undesired ingredients by means of laser irradiation. A laser beam scans the food products according to a predetermined pattern. Variations in the intensity of the laser beam passing through the food products indicate the presence of undesired ingredients. This method is carried out by an apparatus which comprises two parabolic mirrors, a laser emitting a laser beam so as to originate from the focus of one of the mirrors and a detection means positioned in the focus of the other mirror. The food products are moved between the mirrors by conveyor belts.