Detection of foreign bodies in foods using continuous wave terahertz imaging.
Foreign bodies (FBs) in food are health hazards and quality issues for many food manufacturers and enforcement authorities. In this study, continuous wave (CW) terahertz (THz) imaging at 0.2 THz with an output power of 10 mW was compared with X-ray imaging as techniques for inspection  of food for FBs. High-density FBs, i.e., aluminum and granite pieces of various sizes, were embedded in a powdered instant noodle product and detected using THz and X-ray imaging. All aluminum and granite pieces (regular hexahedrons with an edge length of 1 to 5 mm) were visualized by both  CW THz and X-ray imaging. THz imaging also detected maggots (length = 8 to 22 mm) and crickets (length = 35 and 50 mm), which were embedded in samples as low density FBs. However, not all sizes of maggot pieces embedded in powdered instant noodle were detected with X-ray imaging, although  larger crickets (length = 50 mm and thickness = 10 mm) were detected. These results suggest that CW THz imaging has potential for detecting both high-density and low-density FBs embedded in food.
Food Safety Research Center, Korea Food Research Institute, Backhyun 516, Sungnam, Gyeonggi-do 463-746, Republic of Korea.
Young-Ki
YK
Lee
Sung-Wook
SW
Choi
Seong-Tae
ST
Han
Deog Hyun
DH
Woo
Hyang Sook
HS
Chun
D000818:Animals; D005506:Food Contamination / Q000032:analysis*; D005513:Food Inspection / Q000295:instrumentation* / Q000379:methods*; D005547:Foreign Bodies; D006135:Gryllidae; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000295:instrumentation / Q000379:methods; D007814:Larva; D055069:Terahertz Imaging / Q000379:methods*