An Evaluation of the A‐1 Most Probable Number and the Anderson and Baird‐Parker Plate Count Methods for EnumeratingEscherichia coliin the Sydney Rock Oyster,Crassostrea commercialis

摘要

Two rapid methods were evaluated for enumeratingEscherichia coliin the Sydney rock oyster,Crassostrea commercialis.The A‐1, most probable number (MPN) method gave results within 24 h but theEsch. colicounts obtained were considerably lower than those obtained by the more lengthy MPN method recommended by the Standards Association of Australia (SAA). The differences in counts were statistically significant at the 95 confidence level. The membrane‐overlay agar plate method of AndersonBaird‐Parker produced direct counts ofEsch. coliwithin 24 h. At the 95 confidence level, these counts were similar to those found with the SAA method. The AndersonBaird‐Parker method was sensitive and accurate in the range of 2‐5Esch. colicells/g of oyster homogenate as would be required in the regulation of microbiological standards fo