Extraction and concentration procedures for recovering a model virus from pork samples were investigated. A 20-g sample, experimentally contaminated with attenuated poliovirus type 1, was suspended in 100 ml of glycine-NaOH buffer at pH 8.8 and homogenized in an ice bath. The pork solids in the homogenate were flocculated by centrifugation and filtration. Each of the sample extracts was concentrated by either hydroextraction (HE), ultrafiltration (UF), or the polymer two-phase separation (PTPS), and assayed for viruses by the plaque technique in monolayers of HeLa cells. The experiments indicated that the extraction procedure was effective, and that the mean virus recovery from the samples when concentrated by the HE, the UF, and the PTPS was 53.0, 68.0, and 65.1%, respectively. No plaque-forming units were detected in concentrates prepared from uninoculated pork samples. The extraction and concentration procedures developed in the present study are expected to be applicable to the processing of samples for detecting viruses in pork and merit further work.
1Present address: Food Research Institute, University of Wisconsin-Madison, Madison, Wisconsin 53706, U.S.A.