Potentiality of Fourier Transform Infrared Spectroscopy (FTIR) for discrimination and identification of dairy Lactic acid bacteria

Abstract

The potentiality of FTIR spectroscopy for the identification of lactic acid bacteria (LAB) used in the dairy industry was tested. For this purpose, spectra of different strains were recorded using standardized conditions. These strains were species of Lactobacillus (12 species, 3 subspecies), Lactococcus (4 species, 3 subspecies), Leuconostoc (3 species, 3 subspecies), Weissella (1 species) and Streptococcus (2 species) involved in the soft cheese industry. Spectral libraries were then established by statistical analysis. Reference strains were then tested on these libraries, and 100% of correct identifications were obtained at the genus and species level, 86% at the subspecies level. Well-identified strains were included in libraries. Wild isolates (n = 48) previously identified by biochemical tests and RAPD method were then tested. We obtained 100% at the genus level and 69% at the species level of correlation between FTIR and other methods. Finally, spectra of reference strains performed in other laboratories were tested with the same method, and the results tallied with official identification in 100% of the cases at the genus level and in 41% of the cases at the species level. These results concerning a few strains allow us to plan the development of a more complete database for rapid identification of LAB. FTIR spectroscopy / lactic acid bacteria / classification / identificationRésumé -Potentialités de la spectroscopie infrarouge à transformée de Fourier (IRTF) pour la discrimination et l'identification de bactéries lactiques d'intérêt laitier. La discrimination et l'identification de souches de bactéries lactiques d'origine laitière ont été étudiées par spectroscopie IRTF. Les spectres de 28 souches de bactéries lactiques appartenant aux genres Lactobacillus (12 espèces, 3 sous-espèces), Lactococcus (4 espèces, 3 sous-espèces), Leuconostoc (3 espèces, 3 sousespèces), Weissella (1 espèce) et Streptococcus (2 espèces) ont été enregistrés dans des conditions Lait 80 (2000) 445-459 445

Article

“…The recent development of whole bacterium analysis by FTIR (Fourier transform infrared spectroscopy) is of great potential for rapid identification of lactobacilli [1,2,48,49,128]. Bacterial spectra are usually recorded in the mid-infrared.…”

“…The principal advantage of this technique, as pointed out by almost all authors, is its simplicity with respect to genome analysis. Amiel et al [1] established libraries of species used in the cheese industry. Wild strains of lactobacilli isolated from raw milk cheeses from Normandy were well identified.…”

Identification of the Bacterial Microflora in Dairy Products by Temporal Temperature Gradient Gel Electrophoresis

“…Furthermore, bacterial identification by this technique stops at the genus level. More precise bacterial identification techniques use taxonomic and discriminating methods, including biochemical tests, 16S ribosomal DNA (rDNA) sequencing, sodium dodecyl sulfate-polyacrylamide gel electrophoresis of proteins (43), randomly amplified polymorphic DNA fingerprinting (46), and Fourier transform infrared spectroscopy (2). However, these methods are labor-intensive and time-consuming.…”

Potential of FTIR spectroscopy in chemical characterization of Termitomyces Pellets

“…Fourier-transform infrared (FTIR) spectroscopy has been known to be a very promising method to characterize biological samples by their chemical composition and provides qualitative and quantitative estimates of lipids, polysaccharides, nucleic acids, proteins [2,3]. FTIR spectrum is considered as a global "molecular fingerprint" which can be used for characterization, differentiation and identification of microorganisms [1] and has been widely applied for identification of bacteria [3][4][5], yeast, filamentous fungi [6,7] and also some mushrooms [8][9][10]. Various fungal genera have been identified by using dry spores, fruit bodies or cultural biomass as source material for FTIR.…”