Impedance microbiology: quantification of bacterial content in milk by means of capacitance growth curves

The impedancimetric method is a technique for the rapid evaluation of milk bacterial content and also of its subproducts. Several authors have made us e of culture conductance changes during bacterial growth for quantitative a nd qualitative assessments of microbial growth. However, interface capacita nce curves, Ci, have not been used. In this paper, we quantify bacteria in cow raw milk by following their growth as the above-mentioned capacitance c hange time course event. With it, bigger growth variations, shorter detecti on times and a better coefficient of correlation with the plate count metho d were obtained than those yielded by conductance curves. Calibration was p erformed by plotting initial known concentrations, IC (CFU/ml), as a functi on of the time detection theshold (TDT). (C) 1999 Elsevier Science B.V. All rights reserved.