Detecting small metallic contaminants in food via magnetization

Researchers have developed a practical metallic-contaminant detector using three high-Tc RF superconducting quantum interference devices for food inspection. While the detection of small metallic contaminants is important for food safety, the sensitivity of currently existing methods is insufficient. The developed method that uses SQUIDs and a digital filter dramatically improves inspection sensitivity; the method could clearly detect a small steel ball with a diameter as small as 0.3 mm.