Screening slaughtered cattle for BSE

The systematic testing of slaughtered cattle aged over 30 months, or alternatively their elimination from the food chain, is an important component of a package of measures introduced in the European Union on 1 January 2001 to combat bovine spongiform encephalopathy (BSE) and protect human health. Here we explore the analytical limit of a rapid test designed to detect the abnormal prion protein associated with BSE in bovine brain and find that it is comparable to the limit of detection of infectivity in the conventional mouse bioassay1, which is impractical for systematic screening. The sensitivity of the biochemical test allows it to be used as a viable alternative to the destruction of all carcasses of cattle slaughtered after 30 months of age. Additional work is required to compare this analytical sensitivity with the diagnostic sensitivity of the test under conditions of routine post-mortem BSE diagnosis and surveillance.