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United States Department of Agriculture

Agricultural Research Service

Title: Fluorescence Spectoscopy for Detecting Fecal Contamination on Animal Carcasses

Authors
item Casey, Thomas
item Rasmussen, Mark
item Petrich, J - IOWA STATE UNIVERSITY

Submitted to: International Conference on Emerging Zoonoses
Publication Type: Abstract Only
Publication Acceptance Date: December 2, 2002
Publication Date: September 18, 2003
Citation: CASEY, T., RASMUSSEN, M.A., PETRICH, J.W. FLUORESCENCE SPECTOSCOPY FOR DETECTING FECAL CONTAMINATION ON ANIMAL CARCASSES. INTERNATIONAL CONFERENCE ON EMERGING ZOONOSES. 2003. ABSTRACT p. 17.

Technical Abstract: Fecal contamination on the carcasses of slaughtered food animals is an important source foodborne pathogens such as E. coli.O157:H7 and Salmonella. Devices designed to determine the general level of carcass cleanliness would be useful for preventing contaminated food from reaching consumers. Current procedures for identify fecal contamination on meat depend largely on unaided visual inspection of carcasses. However, it can be very difficult to thoroughly inspect carcasses visually because of the rapid chain speeds used in modern meat processing. Improved methods or devices need to be automated for rapid data collection and real-time analysis. Such devices should also be capable of monitoring slaughter process interventions. We have examined several fluorescent markers that may be useful for detecting feces. We found that the most useful markers for a fecal detection system are highly fluorescent chlorophyll metabolites produced during degradation of green plants in the gastrointestinal tract. These metabolites have peak excitation and emission bands near 420 nm and 675 nm, respectively. Chlorophyll metabolites are useful because meat contributes little background fluorescence emissions at the same wavelengths and because the metabolites are commonly present in the G.I. tract and feces of herbivorous animals. We have exploited the fluorescent properties of chlorophyll metabolites for the development of instruments which can detect fecal contamination on carcasses in real-time. Although diet can influence the fluorescent signal, instruments have been designed with sufficient sensitivity for the detection of feces from animals consuming a variety of commercial finishing diets. Fecal detection devices based on detection of fluorescent chlorophyll degradation products have been commercially developed and are currently being installed in slaughter facilities. These instruments can augment other more time-consuming microbiological testing methods and can assist slaughter plant operators and meat inspectors in their efforts to minimize contamination on meat.

Last Modified: 11/23/2014
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