APPLICATION OF MALDI-TOF MASS SPECTROMETRY FOR IDENTIFICATION OF BACTERIA ISOLATED FROM TRADITIONAL SLOVAK CHEESE “PARENICA”

Abstract

In this study, the cultivable population of bacteria from a traditional Slovak cheese “Parenica†made from cow milk were identified using MALDI-TOF mass spectrometry (MS). A total of 100 “Parenica†cheese packages from four producers were examined, including n=50 smoked and n=50 non-smoked cheese samples. The lactic acid bacteria (LAB) were cultured on MRS, APT and MSE agars at 30 °C, coliform bacteria on VRBL agar at 37 °C, total count of bacteria (TCB) on Plate count agar at 30 °C and enterococci on Enterococcus selective agar at 37 °C. Gram-positive and gram-negative strains were subjected to identification by MALDI-TOF MS profiling. MALDI-TOF MS identification revealed four genera belonging to LAB including Lactococcus, Lactobacillus, Enterococcus and Leuconostoc. Lactobacillus was the most represented genus with seven species: Lactobacillus curvatus (L. curvatus), L. delbrueckii, L. fermentum, L. casei, L. paraplantarum, L. plantarum and L. sakei.. Escherichia coli, Enterobacter asburiae, Klebsiella oxytoca and K. pneumoniae were the most identified bacteria species from Enterobacteriales order.