Evaluation of the PetrifilmTM EB and TEMPO® EB systems with ISO 21528-2:2004 method for the count of Enterobacteriaceae in milk

Abstract

The development of alternative microbiological techniques is driven by the necessity to meet the current needs to deliver rapid results in the manufacturing process of foods, but it is important that these methods be evaluated for each application. The objective of the present study was to assess the Petrifilm™ EB and the TEMPO® EB systems with ISO 21528-2:2004 for the count of Enterobacteriaceae in pasteurized and UHT milk samples. We analyzed the microflora of 141 pasteurized milk samples, 15 samples of artificially contaminated pasteurized milk and 15 samples of artificially contaminated UHT milk. Investigation of the method Petrifilm™ EB and ISO 21528:2 regression analysis showed a high correlation in the samples, r = 0.90 for the microflora of pasteurized milk, r = 0.98 for artificially contaminated pasteurized milk and r = 0.99 for the artificially contaminated UHT milk. In evaluating the system TEMPO EB ® method and ISO 21528:2 correlation was also significant in the analyzed samples, with r = 0.86 for the microflora of pasteurized milk, r = 0.96 for artificially contaminated pasteurized milk and r = 0.99 for artificially contaminated UHT milk. No statistically significant differences were observed between the three methods conducted to analyze artificially contaminated pasteurized and UHT milk at three inoculum levels. In conclusion, the Petrifilm™ EB system and the TEMPO® EB system may be an alternative to the ISO 21528-2:2004 for the Enterobacteriaceae assay for milk as because of the ease-of-operation and the time reduction achieved for conducting the microbiological assay using these systems.

Assessment of Lactic Acid Bacteria and Enterobacteriaceae Counts in Bulgarian Probiotic Products by TEMPO® System and ISO Methods

“…Previous comparison studies of TEMPO ® system for examinations of different microbiological parameters (total viable count, coliforms, E. coli count) in various food matrices also showed high correlation with the respective reference methods [2,3,[13][14][15]. As an example, Zitz et al [16] evaluated three TEMPO ® applications to enumerate total viable count, total coliforms and E. coli in milk and soft fresh cheeses and found that the TEMPO ® methods showed equal or better precision and, for some parameters, higher recovery compared to the traditional MPN-based methods.…”

“…Of these, Enterobacteriaceae is usually tested as a hygiene indicator intended to verify the hygiene programs applied at the production premises [2,3].…”