Moon Sung Kim

Each chicken carcass intended for U.S. consumers is mandated to be inspected by Food Safety and Inspection Service (FSIS) inspectors for its wholesomeness at the processing plants. Fluorescence responses of wholesome and unwholesome chicken carcasses were characterized and further evaluated for potential on-line applications for detection and classification of wholesome and unwholesome chicken carcasses. For this study, unwholesome chicken carcasses included cadaver and those with disease conditions such as airsacculitis and septicemia. Fluorescence characteristics from the epidermal layers in the breast areas of chicken carcasses were dynamic in nature. Emission peaks and ridges (maxima) were observed at 386, 444, 472, 512, and 554 nm and valleys (minima) were observed at 410, 460, 484, and 538 nm. One of the major factors affecting the line shapes of fluorescence responses from chicken carcass skin layers was absorption by hemoglobin. With the use of the normalized ratio spectra (NRS) approach, oxyhemoglobin was shown to be a major constituent in chicken carcasses affecting the fluorescence emission line shapes. Subtle line shape changes in the NRS also provided a qualitative means by which to assess the minute differences in oxy- and deoxyhemoglobin compositions perturbed by poultry diseases such as septicemia and airsacculitis. With the use of simple fluorescence band ratios as a multivariate model, wholesome and unwholesome chicken carcasses were correctly classified with 97.1% and 94.8% accuracies, respectively. On-line implementation of fluorescence techniques for the assessment of chicken carcass wholesomeness appears promising.

To determine whether detection of fecal contamination on cantaloupes is possible using fluorescence imaging, hyperspectral images of cantaloupes artificially contaminated with a range of diluted bovine feces were acquired from 425 to 774 nm in responses to ultraviolet‐A (320 to 400 nm) excitation. Evaluation of images at emission peak wavelengths indicated that 675 nm exhibited the greatest contrast between feces contaminated and untreated surface areas. Two‐band ratios compared with the single‐band images enhanced the contrast between the feces contaminated spots and untreated cantaloupe surfaces. The 595/655‐nm, 655/520‐nm, and 555/655‐nm ratio images provided relatively high detection rates ranging from 79% to 96% across all feces dilutions. However, both single band and ratio methods showed a number of false positives caused by such features as scarred tissues on cantaloupes. Principal component analysis (PCA) was performed using the entire hyperspectral images data; 2nd and 5th principal component (PC) image exhibited differential responses between feces spots and false positives. The combined use of the 2 PC images demonstrated the detection of feces spots (for example, minimum level of 16‐μg/mL dry fecal matter) with minimal false positives. Based on the PC weighing coefficients, the dominant wavelengths were 465, 487, 531, 607, 643, and 688 nm. This research demonstrated the potential of multispectral‐based fluorescence imaging for online applications for detection of fecal contamination on cantaloupes.

A laser-induced fluorescence imaging system developed to capture multispectral fluorescence emission images simultaneously from a relatively large target object is described. With an expanded, 355-nm Nd:YAG laser as the excitation source, the system captures fluorescence emission images in the blue, green, red, and far-red regions of the spectrum centered at 450, 550, 678, and 730 nm, respectively, from a 30-cm-diameter target area in ambient light. Images of apples and of pork meat artificially contaminated with diluted animal feces have demonstrated the versatility of fluorescence imaging techniques for potential applications in food safety inspection. Regions of contamination, including sites that were not readily visible to the human eye, could easily be identified from the images.

Fecal contamination of food products is a critical health issue. To test the feasibility of the use fluorescent techniques to detect fecal contamination, fluorescence excitation and emission charac...

We present a detailed description of a laboratory-based multispectral fluorescence imaging system (MFIS) for plant leaves. Fluorescence emissions with 360-nm excitation are captured at four spectral bands in the blue, green, red, and far-red regions of the spectrum centered at 450, 550, 680, and 740 nm, respectively. Preliminary experiments conducted with soybean leaves treated with a herbicide (DCMU) and short-term exposures to moderately elevated tropospheric ozone environment demonstrated the utilities of the newly developed MFIS. In addition, with the aid of fluorescence images of normal soybean leaves, several mechanisms governing the fluorescence emissions are discussed. Imaging results illustrate the versatility of fluorescence imaging, which provides information on the spatial variability of fluorescence patterns over leaf samples.

Terrestrial vegetation studies were carried out in the Italian Northeastern Alps in Val Visdende. The measurement site was 15 Kilometers Northeast of the town of St. Stefano di Calore (Belluno), Italy. Measurements were acquired on a wooded site at the Italian Department of Forestry Station on species native to the Italian Alps. The species included spruce (Picea abies) and alder (Alnus incana) trees. Characterization was also made of the fluorescence responses of several under-story species such as Dactylorhiza fuchsii of the Orchidaceae family, Caltha palustris and Ranunculus ficaria of the Ranuncolcee family, and Trifolium pratense and Trifolium repens of the Leguminosae family. Terrestrial vegetation monitoring was conducted with the Italian FLIDAR remote sensing instrument mounted in a mobile van, the NASA/USDA Fluorescence Imaging System (FIS), and the Spectron SE-590 for optical properties. Photosynthetic CO₂ gas exchange rates we made with LI-COR 6400 infrared gas analyzer. Pigments from the samples were extracted and analyzed with a Perkin Elmer Lamda 7 Spectrometer to determine pigment concentrations. Fluorescence responses were collected from vegetation samples grown under different ambient light regimes of sun-lit versus shaded. The vegetation showed different fluorescence characteristics. A fluorescence algorithm, (F740/F680)/F550, and rate of photosynthesis showed a strong linear relationship.