Estimation of bacterial growth rates from turbidimetric and viable count data

Abstract

The relationship between maximum specific growth rates (μ max) determined from viable counts and turbidemetric measurements for a range of bacterial species is examined in order to assess the potential of turbidemetric methods in predictive microbiology. Two methods for the estimation of μ max from turbidemetric data are presented. One is based on absorbance and the other on transmittance measurements. Both are compared to estimates obtained by viable count methods. Calibration factors, a function to correct the non-linearity of absorbance measurements, and variance stabilising transformations for corrected absorbance measurements and for viable count data, are determined. It is concluded that turbidimetric measurements may be used reliably for estimation of μ max.