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Psihrotrofne bakterije u pravilu čine >70-90% ukupno prisutne mikrobne populacije u ohlađenom sirovom mlijeku. Za mljekarsku industriju od presudne je važnosti brzo određivanje broja psihrotrofnih bakterija u sirovom mlijeku. U 30 uzoraka sirovog mlijeka određivao se ukupan broj psihrotrofnih bakterija metodom protočne citometrije referentnom metodom prema međunarodnoj normi HRN ISO 6730. Identifikacija i klasifikacija bakterija provodila se usporedbom MALDI-TOF spektra masa s referentnim spektrima pohranjenim u bazi podataka i obradom pomoću MALDI Biotyper računalnog programa. MALDI-TOF tehnikom u ohlađenom sirovom mlijeku identificirano je 20 rodova i 35 bakterijskih vrsta. MALDI-TOF tehnika pokazala se prikladnom za brzu i točnu identifikaciju psihrotrofnih bakterija uzgojenih na hranjivoj podlozi, te u kombinaciji s metodom protočne citomerije pruža sveobuhvatniji uvid u mikrobiologiju sastava sirovog mlijeka. Psychrotrophic bacteria generally make up > 70-90% of the total microbial population present in refrigerated raw milk. For the dairy industry, it is crucial to quickly determine the number of psychrotrophic bacteria in raw milk. In 30 raw milk samples, the total number of psychrotrophic bacteria was determined by flow cytometry by reference method according to HRN ISO 6730. The identification and classification of bacteria was performed by comparing the MALDI-TOF mass spectra with the reference spectra stored in the database and processed using the MALDI Biotyper computer program. The MALDI-TOF technique in refrigerated raw milk identified 20 genus and 35 bacterial species. The MALDI-TOF technique has proven to be suitable for the rapid and accurate identification of psychrotrophic bacteria grown on a nutrient medium and in combination with the flow cytometry method, provides a more comprehensive insight into the microbiology of raw milk composition. |
