P2-07 Database Extension for Species Identification in Fermented Products By MALDI-TOF MS:  A Challenge or a Never-Ending Story?

Thursday, 30 March 2017
Marian Awad, Bruker Daltonics, Bremen, Germany
Danièle Sohier, Bruker Daltonics, Bremen, Germany
Simone Becker, Bruker Daltonics, Bremen, Germany
Markus Kostrzewa, Bruker Daltonics, Bremen, Germany
Introduction:  Lactic Acid Bacteria (LAB) and yeasts have helped to preserve foods and beverages for thousands of years by creating an environment unsuitable for food pathogens to survive. LAB and yeasts are used, worldwide, on an industrial scale; but, also, in thousands of local production units, creating thousands of local microbiomes. The description of new species is indeed a never ending-story… But, sometimes, some isolates cause food or beverage spoilage. This definitely makes database implementation for LAB and yeasts identification a challenge; or maybe, as well, a never-ending story!

Purpose:  Opening strategies for developing the database are to focus on fermentation processes, one after another. This helps in creating a road map; starting, first, with processes used at industrial scale, then moving to local productions to enlarge the database, as much as possible.

Methods:  In the step-by-step database implementation program, isolates from dairy, meat, and malt fermentation processes and strains collections were characterized, using both 16S rDNA sequencing and Maldi-TOF Mass Spectrometry (MS). To set up a Reference MS Profile (MSP) for each isolate, a minimum of 20 MSPs were obtained. Whenever possible, three or more different isolates were analyzed per species.

Results:  The database contains, currently, 272 different MSPs representing 104 species of Lactobacillacae and 730 MSPs representing 193 species of yeasts. Blind isolates were analyzed and were accurately identified and distinguished from over 7,311 other microorganisms present in the overall database.

Significance:  The integration of Maldi-Tof MS combined to a fit-for-purpose database into existing fermentation and ripening processes helped to improve quality assurance practices, providing accurate identification and short time to result. This high-throughput, routine platform is a promising technology that can be used to dissect microbiomes from local fermented products and to identify candidates for new starter cultures with specific functionalities.