Abstract: A method and system for detecting foreign particles in the liquid of a full soft drink bottle are described. The bottle under inspection is first passed by a first electronic camera means which memorizes the optical characteristics of a bottle and the fluid contained therein and records these characteristics in the memory of a computer. The bottle under inspection is then rotated either about its vertical axis, or in a preferred embodiment about a horizontal axis to invert the bottle, and just after rotation is moved into the field of view of a second electronic camera means which records in the computer memory the image of the test bottle at this point in time. Any foreign particles within the bottle will tend to undergo movement due to the rotation or inversion of the bottle. Thus, the image detected by the second electronic camera will be different from the image detected by the first electronic camera and indicative of the presence of moving foreign particles within the bottle.