Comparison of Performance of Rapid Petrifilm Test Method and Standard Test Method for Enumeration of Aerobic Microorganisms, Coliforms and E.coli in Food

Abstract

Assuring food safety is currently a global challenge. Frequent testing of food samples for the presence of microorganisms should be performed as part of any food safety program. The conventional tests are in general laborious and time consuming. In this context, the use of alternative rapid tests becomes important. The objective of this study was to compare the performance of Petrifilm test method and standard colony count method for enumerating aerobes, Coliforms and Escherichia coli. The Aerobic Plate Count (APC), Coliform Plate Count (CPC) and E. coli obtained using Rapid Petrifilm test method were compared with the corresponding standard methods using 24 samples of 3 different foods, namely poultry, ready to serve drink (RTS) and milk powder. The counts obtained using Rapid Petrifilm method were not significantly (p<0.05) different from the counts obtained using the conventional methods. The APC obtained using Rapid Petrifilm test method showed a strong correlation with the corresponding conventional method for poultry, RTS and milk powder. The correlation coefficients between the two methods for APC were 0.9934, 0.9988 and 0.9978 for poultry, RTS and milk powder, respectively. The corresponding correlation coefficients for Coliform counts were 0.9891, 0.9940 and 0.9990 while the corresponding correlation coefficients for E. coli were 0.9817, 0.9969 and 0.9983, respectively. The study shows that the Rapid Petrifilm Test method can effectively be used for APC and CPC for foods.