Detection of Central Nervous System Tissue on Meat and Carcass-Splitting Band Saw Blade Surfaces Using Modified Fluorescent Glial Fibrillary Acidic Protein Enzyme-Linked Immunosorbent Assay Sampling and Extraction Procedures

Abstract

This study was conducted to determine optimal buffer pH, extraction procedure, and temperature for detecting central nervous system (CNS) tissue on meat surfaces and on carcass-splitting band saw blades using swab sampling. Glial fibrillary acidic protein (GFAP) is restricted to CNS tissue and has been used as a marker for CNS tissue presence in meat products. Sample preparation, extraction procedure, and extraction temperature of glial fibrillary acidic protein fluorescent enzyme-linked immunosorbent assay (GFAP F-ELISA) were modified to detect CNS tissue on meat surfaces and on carcass-splitting band saw blades. Maximum GFAP recovery was observed with an extraction buffer pH of 7.4. Extracting samples at room temperature by vortexing for 30 s in 1 ml of extraction buffer (phosphate-buffered saline [pH 7.4] plus 0.05% sodium dodecyl sulfate) consistently provided detection of GFAP on meat surfaces contaminated with 500 μg of spinal cord suspension per 50 cm2 and on carcass-splitting band saw blades contaminated with 20 μg of spinal cord suspension per 50 cm2. Recovery of GFAP was not affected by storing samples overnight at 4°C. The current studies demonstrate the effectiveness of modified sampling procedures and preparations, sample extraction buffer pH, and extraction temperatures. These modifications introduced to the original F-ELISA sampling protocol result in a sensitive and repeatable assay for detection of CNS tissue on meat surfaces and on carcass-splitting band saw blades.