Technology Discussion/Explanation:  X-Ray Imaging
X-rays can be used to find defects and foreign materials as well as determine internal properties.  The imaging concept is very similar to the x-rays used in doctors' offices; however, no film is used.  This is the same type of technology used in airports for scanning luggage.  A real-time image is produced using an x-ray source and a camera that is sensitive to x-rays.  Each pixel is sensitive to x-ray flux, which is then used to create an entire image.
 
X-ray image of powder with contaminants This image, supplied by Industrial Research Limited, shows automatically detected contaminants in casein powder at production rates.  The algorithms used allows for automatic inspection of  continuously manufactured food products.  The example image shows a variety of contaminants embedded in the powder.  Starting from the top of the image these are a large void in the powder (not a contaminant), a spring, copper wire, plastic washer, rubber ring and stone.