Author: Csaba Lovász
Experts and laboratories supervising food safety are faced with new challenges by globalized markets, and rapidly changing food industrial technologies and nutrition trends. One of the most important tasks of microbiological laboratories is the analysis of raw materials and products (feeds and foods) entering the food chain, fast and reliable detection and identification of the presence of pathogenic microorganisms. Detection of pathogenic microorganisms might take 5 to 8 days using standard microbiological culture methods, therefore, the emphasis of modern microbiological methods is shifting towards rapid instrumental analyses. Thanks to research in molecular biology, methodologies that can provide reliable results for a large number of samples in a short time are becoming routine laboratory methods.
One of the latest representatives of alternative microbiological methodologies is mass spectrometry (MALDI-TOF) and related software, with the help of which one can identify microorganisms. The acronym MALDI-TOF stands for a special mass spectrometer: MALDI (Matrix Assisted Laser Desorption Ionization) is a photoionization ion source, while TOF (Time of Flight) denotes a time-of-flight mass analyzer. Identification is based on gentically coded proteins found in microorganisms. Each microorganism has a characteristic protein profile that can be used for identification as a sort of fingerprint. This protein profile is determined during MALDI-TOF analysis, and then it is compared to the protein profiles of microorganisms found in the reference library. In this paper, I would like to present the basis of this method, its applicability for the identification of pathogenic microorganisms, and the place of this new methodology among microbiological tests.
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