Utjecaj toplinskog zagrijavanja na stresne parametre odabranih mikroorganizama

undergraduate thesis

• Title (english): Influence of thermal heating on stress parameters of selected microorganisms
• Author: Gloria Hradec
• Mentor: Anet Režek Jambrak (mentor)
• Granter: University of Zagreb; Faculty of Food Technology and Biotechnology; (Department of Food Engineering); (Laboratory for Food Processes Engineering); Zagreb
• Defense date and country: 2017-07-17, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Food Technology

Abstract

Cilj ovog rada je istražiti utjecaj toplinskog zagrijavanja na stresne parametre bakterijske kulture L. innocua, kao surogat patogene L. monocytogenes. Određivan je utjecaj povišene temperature na istjecanje staničnog sadržaja, stupanj redukcije i oporavka, nastanak biofilma kao i na fizikalne čimbenike (pH, provodnost). Uzorci su tretirani pri temperaturnom rasponu 20ºC do 60ºC u vremenskim periodima 5 min i 10 min. Toplinski tretman pokazao se efikasnim pri postizanju redukcije broja tretiranih stanica, a povećanjem temperature i trajanja toplinskog tretmana zabilježeno je pojačano istjecanje unutarstaničnog sadržaja, smanjenje pH vrijednosti, povećanje provodnosti te je zabilježena pojava slobodnih radikala kao posljedica oksidacijskog stresa u stanici. Također je i zabilježen nastanak biofilma kao posljedica izlaganja stanica stresnim uvjetima. Oporavak stanica zabilježen je pri temperaturama 20ºC do 50ºC. Pri 60ºC nije došlo do oporavka tretiranih stanica.

Abstract (english)

The aim of this work is to investigate the influence of heating on the stress parameters of bacterial culture L. innocua, as a surrogate of the pathogenic L. monocytogenes. The influence of elevated temperature on the leakage of intercellular content, the degree of reduction and recovery, biofilm formation as well as physical factors (pH, conductivity) were determined. The samples were treated at a temperature range of 20ºC to 60ºC in time periods of 5 min and 10 min. Heat treatment was shown to be effective in reducing the number of treated cells. Increased temperature and duration of heat treatment resulted in increased leakage of intercellular content, increased concentracion of free radicals resulting from oxidative stress, decreased pH value, increased conductivity and biofilm formation. Recovery of the cells was recorded at temperature range of 20ºC to 50ºC. At 60ºC there was no recorded recovery of treated cells.

• Keywords: biofilm; L. innocua; oporavak; redukcija; toplinsko zagrijavanje
• Keywords (english): biofilm; heating; L. innocua; recovery; reduction
• Language: croatian
• URN:NBN: urn:nbn:hr:159:188212
• Study programme: Title: Food Technology; Study programme type: university; Study level: undergraduate; Academic / professional title: sveučilišni/a prvostupnik/prvostupnica (baccalaureus/baccalaurea) inženjer/inženjerka prehrambene tehnologije (sveučilišni/a prvostupnik/prvostupnica (baccalaureus/baccalaurea) inženjer/inženjerka prehrambene tehnologije)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2017-07-17 08:20:23