Evaluation of the robustness of FT-IR spectra of lactobacilli towards changes in the bacterial growth conditions.

In order to use Fourier Transform Infrared (FT-IR) spectroscopy for identification of microorganisms on a routine basis, it is important that the spectra are robust against small, uncontrollable variations in the bacterial growth conditions. In this study, the effect of small variations in growth temperature, growth time, growth medium and atmospheric conditions on the separation of Lactobacillus based on their FT-IR spectra was investigated. The resulting spectra were shown to be robust against the variations in the cultivation conditions, and the separation of both strains and species was unaffected. Larger variations in the growth medium influenced only the separation of strains. FT-IR spectroscopy for identification of lactobacilli therefore seems to be robust against small variations in the cultivation conditions.