Food chemist Dr. Jörg Rau works as head of the department for food of animal origin at the Chemical and Veterinary Analysis Agency Stuttgart (CVUAS) as a part of official food control in the state of Baden-Württemberg, Germany. His longstanding areas of experience include the use and further development of identifying spectroscopy (FT-IR, MALDI-TOF MS) for food testing and veterinary diagnostics.
MALDI-TOF mass spectrometry (MALDI-TOF MS) is used for many applications in food analysis. The identification of an unknown protein containing sample is achieved by comparing the obtained mass spectrum with reference spectra stored in a database. The appropriate database is the key for a reliable identification. The instrument and software systems used by most users allow easy creation of custom reference entries. These are transferable within a given instrument platform, and therefore can be shared by different institutions. Thus, the creation of reference spectra has only to be done once for various laboratories. In addition to microorganisms, for which manufacturers already offer extensive databases, own supplements can also be developed for other topics. Examples are the differentiation of animal species in muscle meat and cheese by MALDI-TOF MS to reveal potential food fraud. Also, the rapid establishment of these applications in the laboratory is promoted by collegial exchange.
To provide details of existing, high quality database entries by users for users, a list has been compiled and made available for download from the non-commercial MALDI-UP website (https://www.maldi-up.ua-bw.de). MALDI-UP provides an actual overview of existing database entries and contact details of the respective creator of the entries, allowing bilateral exchange. This offer is used by an increasing number of users. As of the beginning of 2021, more than 2000 reference spectra from 27 institutions from different application areas are listed, including more than 600 entries on meat, 150 entries on dairy products and more than 900 entries on microorganisms. In addition, detailed information on more than 4500 individual single spectra is provided in a further section, which can also be passed on for validation purposes. MALDI users interested in non-commercial sharing are invited to use MALDI-UP.