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Digestion of green plants in the gastrointestinal (GI) tract produces degradation products from chlorophyll (figure below) that cause ingesta and feces to be highly fluorescent. This property was exploited for development and construction of instruments to noninvasively, detect minute quantities of feces on meat samples in real time. The presence of feces on meat products is a primary source of foodborne pathogens, such as E. coli O157:H7 and Salmonella. This new technology provides a rapid and accurate alternative to the practice of visual inspection and augments more time-consuming biological testing methods. This innovation can assist meat processors and government inspectors in their efforts to provide safe and wholesome food to consumers. |
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Chlorophyll metbolite |
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Fecal Contamination |
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We, and Tom Casey and Mark Rasmussen of the National Animal Disease Center, USDA, ARS have patented this technology, which has won several awards, including an R&D100 award in 2000. |
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Our former student, Kyle Ashby, is shown with a hand held prototype of the device that we constructed |
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Microbiologists Tom Casey (left) and Mark Rasmussen evaluate a new laser for use in their fecal contamination detection system for meat carcasses in Petrich Lab |
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CNS Tissue Contamination |
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Visible Image of Clear test Solution and Contaminated Beef |
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Food Safety Illuminated Image of Clear Test Solution and Contaminated Beef . Red fluorescence indicated presences of feces |
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Bovine spongiform encephalopathy (BSE) is a fatal, neurodegenerative transmissible spongiform encephalopathy (TSE) in cattle. This is also thought to be the cause of variant Creutzfeldt - Jakob disease (vCJD) in humans. Removal of bovine specified risk materials (SRMs, e. g. brain and spinal cord) from the human food chain is of critical importance for protecting consumers from BSE. |
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After processing in the slaughter house, traces of CNS tissues may be found in meat. |
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Comparison of Fluorescence intensity from different bovine CNS and non-CNS tissues |
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CNS tissues showed much higher fluorescence compared to non-CNS tissues Efforts are in progress in our laboratory to develop a prototype for the detection CNS contaminations in meat. |
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Fluorescence from Murine and Sheep Eyes |
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It is believed that the aging process in humans and animals is accompanied by the progressive accumulation of yellow-brown intracellular pigments,.classically known as “lipofuscin”. Lipofuscin is believed to be the product of “oxidative stress” which accumulates in central nervous system (CNS) tissues, and also in the eye, especially in the case of disease; and this is possibly related to age-related macular degeneration and other pathologies |
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The goal of this study was to monitor the accumulation of lipofuscin in murine eyes, to compare these spectra with those from eyes from other species, and to compare these data with other tissues. |
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Dissection of Sheep Eye inside a Biosafety hood |
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White mouse |
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Our study indicates that fluorescence may be used as an indicator of age. We note that our present study with mice can be considered as a representative marker for age which appears related to the accumulation of fluorescent pigment (lipofuscin) in eyes, which could be easily extended to similar studies in other animals like sheep, cow and perhaps even in humans. |
