Utjecaj ultrazvuka visoke snage na inaktivaciju i revitalizaciju odabranih mikroorganizama

undergraduate thesis

• Title (english): Influence of high intensity ultrasound on inactivation and recovery of selected microorganisms
• Author: Iva Šušić
• 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: 2017-09-19, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Food Technology

Abstract

Svrha ovog rada je utvrditi utjecaj ultrazvuka visoke snage na inaktivaciju i revitalizaciju bakterijske kulture Listeria innocua ATC 33090. Određivan je utjecaj na istjecanje staničnog sadržaja, stupanj redukcije, oporavka te na fizikalne čimbenike (pH, provodnost). Uzorci su ultrazvučno tretirani sondom frekvencije 20 kHz uz tri nezavisne varijable, amplituda (75%, 100%), vrijeme tretmana (5min, 10 min) i temperatura (40°C, 60°C). Rezultati su analizirani metodom odzivne površine (RSM) koristeći program STATGRAPHICS Centurion. Najviša inaktivacija bakterijske kulture od 4,309 log10 CFU/mL postignuta je pri 40°C i 100% amplitudi, no također pri tim uvjetima postignut je i potpuni oporavak. Potpuna inaktivacija bez oporavka postignuta je pri 60°C i 75% amplitudi nakon 10min tretmana te pri 60°C i 100% amplitudi što potvrđuje i istjecanje staničnog sadržaja prema apsorbancijama pri 260nm i 280nm.

Abstract (english)

The aim of this final work is to determine the influnece of high intensity ultrasound on reduction and recovery of Listeria innocua ATCC 33090. The influence of high intensity ultrasound on the leakage of intercellular content, the degree of reduction and recovery as well as physical factors (pH, conductivity) were determined. Samples were treated with the ultrasound probe with a frequency of 20 kHz with three independent variables, amplitude (75 %, 100 %), duration of treatment (5min, 10 min) and temperature (40 °C, 60 °C). The results were analyzed by surface method (RSM) using the STATGRAPHICS Centurion program. The highest reduction of microorganisms (4,309 log10 CFU/mL) was achieved at 40°C and 100% of amplitude, but also at that conditions full recovery was achieved. Full inactivation without recovery was achieved after 10min of treatment at 60°C with 75% amplitude and also at 60°C with 100% amplitude what confirms leakaging of intercellular content according to absorbency at 260nm and 280nm.

• Keywords: ultrazvuk visoke snage; inaktivacija; revitalizacija; mikroorganizmi
• Keywords (english): high intensity ultrasound; inactivation; recovery; microorganisms
• Language: croatian
• URN:NBN: urn:nbn:hr:159:575499
• 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: 2017-10-03 12:42:45