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United States Department of Agriculture

Agricultural Research Service


item Rasmussen, Mark
item Casey, Thomas
item Petrich, J

Submitted to: Federation of Animal Science Societies
Publication Type: Abstract Only
Publication Acceptance Date: 3/15/2004
Publication Date: 7/25/2004
Citation: Rasmussen, M.A., Casey, T., Petrich, J.W. Meat carcass inspection using the fluorescence of dietary porphyrins [abstract]. 2004 Joint Annual Meeting of the American Dairy Science Association, American Society of Animal Science, Poultry Science Association. p. 166.

Interpretive Summary:

Technical Abstract: Feces on animal carcasses are an important source of foodborne pathogens. Imaging devices that could assess the general level of carcass contamination would help to provide high quality meat products to consumers. Inspection procedures have relied upon unaided visual examination of carcasses but it is difficult to thoroughly inspect all carcasses in high speed processing plants using visual means. Imaging technology with real-time capabilities and automated inspection would improve current procedures. In our research we have examined several fluorescent markers that could be used to optically detect fecal material. Excitation and emission spectra and fluorescent lifetime measurements were obtained for a variety of ingesta and fecal samples from cattle and other livestock species. Our analysis found that the most useful markers for fecal detection were the highly fluorescent metabolites of chlorophyll (pheophorbide and pyropheophorbide). These metabolites have peak excitation and emission wavelengths near 420 nm and 675 nm, respectively. These metabolites are normally present in the G.I. tract of herbivorous animals consuming green plant material. These markers are particularly useful because the background fluorescence of meat is low in the far-red region of the visible spectra. We have exploited the fluorescent properties of these chemical markers in the development of instruments, which can detect fecal contamination on meat animal carcasses. Although diet can influence the fluorescent signal obtained, instruments have been designed with adequate sensitivity for the detection of feces from animals consuming a variety of commercial feedlot rations. This imaging technology has been developed through intellectual property protection and technology transfer into commercially produced instruments, which are currently being manufactured and used by the meat-processing industry. These instruments augment 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: 09/21/2017
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