Evaluation of the Petrifilm plate method for the enumeration of aerobic microorganisms and coliforms in retailed meat samples

This study was designed to compare the effectiveness and applicability of t he Petrifilm plate method with the Association of Official Analytical Chemi sts' (AOAC) standard aerobic count method and violet red bile agar method f or meat products. The comparison was carried out using 303 meat samples col lected from various retailers: 110 pork samples, 87 chicken samples, and 10 7 beef samples. In the comparison of the correlation coefficient (R) betwee n the conventional method and the Petrifilm plate method by a linear regres sion analysis, the correlation coefficient in total microorganisms was 0.99 , 0.95, and 0.94 in pork, beef, and chicken samples, respectively. The corr elation coefficient in coliform count was 0.83, 0.96, and 0.81 in pork, bee f, and chicken samples, respectively. Based on the high correlation in the total microorganism count, it might be possible to replace the conventional methods with the Petrifilm plate method. For coliform counts, the Petrifil m plate method also showed a generally high correlation coefficient, except for pork samples, which are more subject to contamination. The Petrifilm p late method was simpler and less time-consuming in sample preparation and, in procedures, faster than the conventional method. These results suggested that the 3M Petrifilm plate method could replace the conventional methods in the analysis of microorganism contamination measurement in meat products .