MULTISPECTRAL FLUORESCENCE IMAGING TECHNIQUES FOR NONDESTRUCTIVE FOOD SAFETY INSPECTION

Authors: Kim, Moon; Lefcourt, Alan; Chen, Yud

Submitted to: Proceedings of SPIE
Publication Type: Proceedings
Publication Acceptance Date: 10/29/2003
Publication Date: 10/29/2003
Citation: Kim, M.S., Lefcourt, A.M., Chen, Y.R. 2003. Multispectral fluorescence techniques for non-destructive food safety inspection. SPIE Proceedings entitled: Monitoring Food, Safety, Agriculture, and Plant Health. 5271:62-72.

Interpretive Summary: Government regulations stipulate no-visual evidence of animal fecal matter on meats and on fruits used to make unpasteurized juices. Feces from dairy cows and deer are known sources of disease causing bacteria. To this date, there are no reliable optical sensing systems that can be employed in the food processing plants for detection of animal fecal contaminations. Our laboratory has been exploring fluorescence as a potential means for detection of fecal contamination. Researchers at the ISL have developed several imaging systems based on fluorescence techniques. These systems include hyperspectral fluorescence imaging, and laser-induced fluorescence (LIF) and transportable steady-state fluorescence imaging systems with multispectral capabilities. The versatility of the fluorescence imaging systems are demonstrated with apples empirically contaminated with dilute cow feces. Regions of fecal contamination that is not readily visible to human eye are easily identified by the multispectral fluorescence images. Presented sensing systems and methodologies are useful to food scientists, engineers, regulatory government agencies (FSIS and FDA), and food processing industries.

Technical Abstract: The use of spectral sensing has gained acceptance as a rapid means for nondestructive inspection of postharvest food produce. Reflectance in the Vis/NIR is the prevalent spectral technique. Fluorescence, compared to reflectance, is regarded as a more sensitive technique due to its dynamic responses to subtle changes in biological entities. Our laboratory has been exploring fluorescence as a potential means for detection of quality and wholesomeness of food products. Because of relatively low fluorescence quantum yield from biological samples, a system with a powerful pulse light source such as a laser coupled with a gated detection device is used to harvest fluorescence, in the presence of ambient light. Several fluorescence sensor platforms developed in our laboratory, including hyperspectral imaging, and laser-induced fluorescence (LIF) and steady-state fluorescence imaging systems with multispectral capabilities are presented. We demonstrate the potential uses of recently developed fluorescence imaging platforms in food safety inspection of apples contaminated with animal feces.