DETECTION OF PSYCHROTROPHIC BACTERIA ON MEAT SURFACES BY AN INDIRECT ELISA USING POLYCLONAL ANTIBODIES AGAINST LIVE CELLS OF PSEUDOMONAS-FLUORESCENS

Polyclonal antibodies raised against live cells of Pseudomonas (Ps.) f luorescens AH-70 have been used in an indirect enzyme-linked immunosor bent assay (ELISA) for detection of Ps. fluorescens and related psychr otrophic bacteria in refrigerated meat. These anti-live cells antibodi es were recovered from the crude antiserum by ammonium sulfate precipi tation and conjugated to biotin. Commercial ExtrAvidin-peroxidase conj ugate was used to detect the biotinylated antibodies bound to their sp ecific antigens. Subsequent enzymatic conversion of substrate gave dis tinct absorbance differences when assaying meat samples containing Ps. fluorescens strains of different origin as well as related psychrotro phic microorganisms. The detection threshold for the ELISA assay devel oped in this work was 10(4) to 10(5) cfu/cm(2).