magistrsko delo
Vesna Blagojević (Author), Rok Fink (Reviewer), Klemen Bohinc (Mentor), Anamarija Zore (Co-mentor)

Abstract

Uvod: Mikrobiološka kontaminacija površin, ki prihajajo v stik z živili predstavlja velik higienski problem, saj lahko mikroorganizmi povzročijo kvarjenje živil in okužbe povezane s hrano. Eden glavnih vzrokov za pojav izbruhov okužb povezanih s hrano, je sekundarna kontaminacija živil z mikroorganizmi, pritrjenimi na kuhinjske površine. V domačih kuhinjah so z mikroorganizmi najpogosteje onesnažene deske za rezanje, različni kuhinjski pripomočki, krpe, kuhinjski ročaji ter kuhinjski pulti. Prvi in najpomembnejši korak za mikrobiološko kontaminacijo površin, je adhezija tj. začetni privlak med mikroorganizmi in površino ter pritrjevanje celic na površino. Na bakterijsko adhezijo vplivajo dejavniki okolja, lastnosti površin ter lastnosti mikroorganizmov. Namen: Namen naše študije je bil ugotoviti stopnjo adhezije bakterije Escherichia coli na pogosto uporabljene kuhinjske površine (bukev, granit, iveral in Teflon) ter ugotoviti vpliv UV-C svetlobe na preživetje Escherichia coli na izbrani površini. Metode dela: Vse analizirane površine so bile izpostavljene enakim okoljskim dejavnikom. Vzorčnim površinam smo določili hrapavost, omočljivost in pretočni potencial. Število adheriranih bakterijskih celic smo določali po metodi decimalne razredčitve, s sprotnim nacepljanjem na gojišče. Učinkovitost UV dezinfekcije smo določali takoj po kontaminaciji izbrane površine z bakterijo Escherichia coli in po 24 urni inkubaciji. Rezultati: Največja hrapavost je bila izmerjena na lesu, sledita pa mu Teflon in iveral. Najbolj hidrofoben material je Teflon, sledijo pa mu les, iveral in granit. Vse vzorčne površine imajo negativen naboj. Rezultati kažejo, da je največja stopnja adhezije bakterije Escherichia coli izmerjena na Teflonu, sledi iveral, les in granit. Ugotovili smo tudi, da je učinkovitost UV dezinfekcije nižja po 24 urni inkubaciji. Razprava in zaključek: Na podlagi rezultatov smo ugotovili, da na adhezijo Escherichia coli na izbrane kuhinjske površine bolj vpliva hidrofobnost, kot površinska topografija. Ugotovili smo tudi, da je po tretiranju z UV-C svetlobo po 24 urni inkubaciji bakterij na površini Teflona preživelo več bakterijskih celic, kot pri tretiranju z UV-C svetlobo neposredno po kontaminaciji površine z Escherichia coli.

Keywords

magistrska dela;sanitarno inženirstvo;bakterijska adhezija;kuhinjske površine;lastnosti površin;UV dezinfekcija;

Data

Language: Slovenian
Year of publishing:
Typology: 2.09 - Master's Thesis
Organization: UL ZF - University College of Health Studies
Publisher: [V. Blagojević]
UDC: 614
COBISS: 120955139 Link will open in a new window
Views: 28
Downloads: 14
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Other data

Secondary language: English
Secondary title: Escherichia coli adhesion capacity to kitchen worktops - beech wood, stone, coated particle board and Teflon
Secondary abstract: Introduction: Microbiological contamination of food contact surfaces is a major hygiene problem, as microorganisms can cause food spoilage and foodborne infections. Secondary contamination of food with microorganisms attached to kitchen surface is one of the main causes of outbreaks of food-related infections. Cutting boards, various kitchen utensils, cloths, kitchen handles and kitchen counters are the most common source of microorganisms in domestic kitchen. The first and most important step of microbiological surface contamination is adhesion, i. e. initial attraction between microorganisms and the surface. Bacterial adhesion is influenced by environmental factors, surface properties and the properties of microorganisms. Purpose: Purpose of our study was to determine the adhesion level of Escherichia coli to commonly used kitchen surfaces (beech, granite, coated particle board and Teflon) and to determine the effect of UV light on the survival of Escherichia coli on selected surface. Methods: All analysed surfaces were exposed to the same environmental factors. We determined the sourface roughness, wettability and flow potential. The number of adhered bacterial cells was determined by the method of decimal dilution followed by drop plate method. The effectiveness of UV disinfection was determined immediately after contamination of the selected surface with Escherichia coli and after 24 hours of incubation. Results: The highest roughness was measured for wood, followed by Teflon and coated particle board. The most hydrophobic material is Teflon, following by wood, coated particle board and granite. All of the sampled surfaces possess negative charge. Results show the highest level of Escherichia coli on Teflon, followed by coated particle board, wood and granite. We also found that efficiency of UV disinfection is lower after 24 hours when compared to 0,5 h of incubation. Discussion and conclusion: Based on these results, we concluded, that the adhesion of Escherichia coli on chosen surfaces is mainly influenced by hydrophobicity, when compared to surface topography. Moreover, the UV disinfection is more efficient directly after contamination of surface with Escherichia coli, than after 24 hour incubation of bacteria on surface.
Secondary keywords: master's theses;sanitary engineering;bacterial adhesion;kitchen surfaces;surface properties;UV disinfection;
Type (COBISS): Master's thesis/paper
Study programme: 0
Thesis comment: Univ. v Ljubljani, Zdravstvena fak., Oddelek za sanitarno inženirstvo
Pages: 49 str., [2] str. pril.
ID: 16429413