Abstract: A light source, a light projecting body, a plurality of optical fiber bundles and a sensor is provided. The light projecting body is provided with a central bore along which the sensor is aligned and a plurality of passages for a respective fiber bundle extending therethrough in communication with the central bore. The central bore is equal to or larger than the mouth of the bottle to be examined and the apertures terminate in connection with the central bore at a point lying in a circle on the central bore corresponding substantially to the periphery of mouth of the bottle, the longitudinal direction of the passages are substantially coincident with a tangent to their associated terminal point.