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

FELICE, CARMELO JOSÉ; MADRID, ROSSANA ELENA; OLIVERA, JUAN MANUEL; ROTGER, VIVIANA INÉS; VALENTINUZZI, MÁXIMO EUGENIO

Journal of Microbiological Methods

Año: 1999 vol. 35 p. 37 - 42

The impedancimetric method is a technique for the rapid evaluation of milkbacterial content and also of its subproducts. Several authors have made use of cultureconductance changes during bacterial growth for quantitative and qualitativeassessments of microbial growth. However, interface capacitance curves, Ci, have notbeen used. In this paper, we quantify bacteria in cow raw milk by following their growthas the above-mentioned capacitance change time course event. With it, bigger growthvariations, shorter detection times and a better coefficient of correlation with the platecount method were obtained than those yielded by conductance curves. Calibrationwas performed by plotting initial known concentrations, IC [CFU/ml], as a function ofthe time detection theshold (TDT).