Identifikacija mikrobioloških povzročiteljev kvarjenja piva z masno spektrometrijo

Troha, Simon (author), Smole Možina, Sonja (mentor)

Pivo zaradi svojih lastnosti velja za mikrobiološko varno. Kljub temu pa je mikrobiološki kvar piva pogost problem v pivovarski industriji in razlog ekonomskih izgub. Med mikrobiološke povzročitelje kvarjenja spadajo tako grampozitivne kot gramnegativne bakterije in divje kvasovke, kontaminacija pa lahko povzroči motnost, kislost in spremembo okusa piva. Z naraščajočo priljubljenostjo nepasteriziranih, brezalkoholnih piv in piv z nizko vsebnostjo alkohola pa to predstavlja še toliko večjo skrb za pivovarsko industrijo. Za učinkovito odpravljanje težav je potrebna hitra in zanesljiva identifikacija bakterijskih vrst in tudi razlikovanje sevov iste vrste. Identifikacija bakterij v pivu večinoma poteka z uporabo standardnih fenotipskih testov po izolaciji na selektivnih gojiščih, kar je časovno potraten in manj specifičen postopek. Posledično se zaradi dolgotrajne analize povečajo tudi stroški skladiščenja in potreba po večji skladiščni kapaciteti. Ena od možnih načinov za hitro in zanesljivo identifikacijo mikroorganizmov v pivu je identifikacija z MALDI-TOF masno spektrometrijo (angl. matrix assisted laser desorption/ionization time-of-flight mass spectrometry). V diplomskem delu so predstavljeni najbolj pogosti mikrobiološki povzročitelji kvarjenja piva in njihova rezistenca na hmeljne spojine kot ključen faktor za zmožnost rasti v pivu. Predstavljena je tudi mikrobiološka identifikacija teh povzročiteljev z MALDI-TOF masno spektrometrijo v primerjavi z ustaljenimi metodami.

• Language: Slovenian
• Keywords: pivo, mikroorganizmi, bakterije, kvasovke, kvar piva, masna spektrometrija, identifikacija mikroorganizmov, MALDI-TOF MS
• Work type: Bachelor thesis/paper
• Typology: 2.11 - Undergraduate Thesis
• Organization: BF - Biotechnical Faculty
• Publisher: [S. Troha]
• Year: 2019
• PID: 20.500.12556/RUL-109799
• UDC: 579.67:663.4:543.51
• COBISS.SI-ID: 5093496
• Publication date in RUL: 08.09.2019

TROHA, Simon, 2019, Identifikacija mikrobioloških povzročiteljev kvarjenja piva z masno spektrometrijo [online]. Bachelor’s thesis. S. Troha. [Accessed 11 August 2025]. Retrieved from: https://repozitorij.uni-lj.si/IzpisGradiva.php?lang=eng&id=109799

Secondary language

• Language: English
• Title: Identification of microbiological spoilers of beer with mass spectrometry

Abstract

Beer is, according to its properties, considered as microbiologically safe beverage. However, there are numerous reported events of beer spoilage due to the presence of microorganisms, which are a big problem in the brewing industry and reason for important economic losses. Beer spoilers belong to groups of Gram-positive, Gram-negative bacteria and wild yeasts and their presence can lead to beer turbidity, acidity and unwanted flavour. With the increased popularity of unpasteurized, nonalcoholic and low-alcoholic beers, beer-spoilage organisms present even greater problem for the brewing industry. Effective problem solution therefore demands quick and reliable identification of beer spoilers to species and/or strain level. However, bacterial identification in most laboratories is still carried out by traditional methods such as incubation on culture media and subsequent characterization through biochemical and other tests, which are labour-intensive and very time-consuming tasks. This increases storage expenses and the need for bigger storage capacity. One of the approaches for quick microbiological identification is the implementation of MALDI-TOF MS (matrix assisted laser desorption/ionization time-of-flight mass spectrometry) instrument into standard microbiological practice. The thesis presents main beer spoilers and their resistance to hop compounds as the key factor for their growth in beer. It also presents microbiological identification by MALDI-TOF mass spectrometry and compares it with the standard methods in the brewing microbiological laboratory.

• Keywords: beer, microorganisms, bacteria, yeasts, beer spoilage, mass spectrometry, identification of microorganisms, MALDI-TOF MS