Comparative analysis of milk bacteria by two MALDI-MS systems

This study presents a comparative analysis of bacterial strains isolated from raw milk using two. MALDI-TOF MS systems: the Bruker Microflex LT Biotyper and the newer Zybio EXS2600 Ex-Accuspec. A total of 1,130 isolates were identified using the in-tube extraction method. The aim of the study was to assess identification accuracy at the genus and species levels. Both systems demonstrated high performance: the Bruker system identified 94.6% of the isolates to at least the genus level, and the Zybio system identified 91.3%. Both MALDI systems showed a high level of agreement at the species level - approximately 75% of Bruker identifications matched those obtained with the Zybio system. In the remaining ~ 25% of cases, discrepancies were observed at both the species and genus levels. The results indicate that both systems offer a comparable level of effectiveness for routine use. in microbiological diagnostics.