Comparison of TEMPOp EC and TBX medium for the enumeration of Escherichia coli in cheese

摘要

TEMPOp EC (Escherichia coli) is based on glucuronidase activity and is a test for use with the TEMPO system for the automated 24 h enumeration of E. coli in food products. In this study, TEMPO EC was compared with TBX medium, the current standard plate method for the enumeration of E. coli in cheese. For comparative purposes, both naturally (92) and artificially contaminated (31) cheese samples were studied. Pearson correlation coefficients were determined as 0.954 and 0.978 between the two methods for naturally and artificially contaminated samples, respectively. Regression analysis yielded the following equations: log TEMPO EC = 0.340 + 0.889 log TBX medium and log TEMPO EC = 0.174 + 0.899 log TBX medium for naturally and artificially contaminated samples, respectively. In general, absolute differences did not exceed one log between results obtained by the two methods. Statistical analysis of the results showed good agreement between the two enumeration methods. TEMPO EC is a practical and reliable alternative to the current standard plate method for the enumeration of E. coli in foods.