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Gewählte Master / Diploma Thesis:

Patrick Danka (2018): MALDI-TOF MS-based identification of food chain-related lactobacilli.
Master / Diploma Thesis - Institut für Lebensmittelwissenschaften, BOKU-Universität für Bodenkultur, pp 106. UB BOKU obvsg

Data Source: ZID Abstracts
Abstract:
Fast and reliable detection of food-associated bacteria is essential for food quality and safety. Lately, Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF MS) has emerged as a powerful tool for the identification of food chain-related microorganisms, such as Lactobacillus spp., and it has been more frequently used instead of time-consuming conventional techniques due to its superior accuracy, rapidity and cost-efficiency. The identification is based on mass spectral fingerprints, which are matched and compared to reference mass spectra in the reference database. In this study, the MALDI Biotyper (Bruker) was used for the species-level identification of 383 Lactobacillus strains, with either on-plate or off-plate formic acid extraction applied for sample preparation. In addition, 15 further Lactobacillus species were included to the MALDI Biotyper database to enable more reliable identification for a wider pool of Lactobacillus spp. isolates. As a result, all 383 strains were identified correctly to genus level with at least one of the applied preparation techniques. For 369 of these strains, there was accurate genus-level identification with both methods. With the optimization, the identification rates were 97.7% and 98.7% at genus level, while 83.0% and 87.2% at species level for the on-plate and off-plate extraction, respectively. The latter yielded higher scores in significantly more cases and better species consistency could be established with it. However, the number of measurements where isolates were identified correctly was almost identical for the two methods. This study has proven that both, the on-plate and off-plate techniques are suitable and reliable for the identification of Lactobacillus species, but results that are more accurate at species level can be achieved with the off-plate extraction method. In conclusion, MALDI-TOF MS is an excellent tool for the accurate identification of Lactobacillus spp. isolates.

Beurteilende(r): Domig Konrad

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