Utjecaj parametara na preživljavanje bakterije Listeria monocytogenes

undergraduate thesis

• Title (english): Influence of environment parameters on the survival of the Listeria monocytogenes bacterium
• Author: Vitka Gres
• Mentor: Ksenija Markov (mentor)
• Granter: University of Zagreb; Faculty of Food Technology and Biotechnology; (Department of Biochemical Engineering); (Laboratory for General Microbiology and Food Microbiology); Zagreb
• Defense date and country: 2014-09-11, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Biotechnology

Abstract

Cilj ovog rada je bio ustvrditi preživljavanje bakterije Listeria monocytogenes u hranjivom bujonu i mlijeku pri različitim temperaturnim uvjetima tijekom različitog vremenskog perioda. Listeria monocytogenes ima veliku toleranciju na ekstremne uvjete okoliša, pa tako može preživjeti uz raspon pH od 4,3 do 10 i na temperaturama od <1 °C do 45 °C. Rezultati istraživanja pokazali su da bakterija L. monocytogenes dobro preživljava pri temperaturi od 4°C, oko 62% stanica preživjelo je temperaturni tretman smrzavanjem na -20°C tijekom 21 dan, dok zagrijavanje uzoraka na 80°C/10 min smanjuje broj živih stanica za 4-5 log jedinica. Kombinacijom temperatura, zagrijavanje na 80°C/10 min, a zatim pohranjivanje uzoraka na -20°C može se značajno smanjiti pa čak i potpuno uništiti L. monocytogenes.

Abstract (english)

This thesis researches the Listeria monocytogenes bacterium and tries to establish it’s survival parameter at different temperature conditions in different time periods in different mediums (broth and milk). It has great tolerance for extreme environmental conditions, and it can survive in pH range between 4.3 and 10 and temperatures from 1 °C to 45 °C. Results show that the bacteria has a good survival rate at 4°C, about a 62% survival rate after a temperature treatment which involved freezing to -20°C during 21 days, while heating the sample to 80°C in a time period of 10 minutes reduces the cell count for 4-5 log units. Combinig the heating and freezing procedure can greatly reduce and even destroy L. monocytogenes.

• Keywords: Listeria monocytogenes; temperatura; bujon; mlijeko
• Keywords (english): Listeria monocytogenes; temperature; broth; milk
• Language: croatian
• URN:NBN: urn:nbn:hr:159:952790
• Study programme: Title: Biotechnology; Study programme type: university; Study level: undergraduate; Academic / professional title: sveučilišni/a prvostupnik/prvostupnica (baccalaureus/baccalaurea) inženjer/inženjerka biotehnologije (sveučilišni/a prvostupnik/prvostupnica (baccalaureus/baccalaurea) inženjer/inženjerka biotehnologije)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Access restricted to students and staff of home institution
• Created on: 2017-04-26 11:43:03