Utjecaj pohrane na rast bakterije L. monocytogenes u kuhanom kravljem siru

master's thesis

• Title (english): Occurence of Listeria monocytogenes in boiled cow cheese
• Author: Josipa Rožić
• Mentor: Lidija Kozačinski (mentor)
• Committee member: Estella Prukner-Radovčić
• Committee member: Ivana Filipović
• Committee member: Lidija Kozačinski
• Granter: University of Zagreb; Faculty of Veterinary Medicine; (Department of Hygiene and Technology of Foodstuffs); Zagreb
• Defense date and country: 2014-02-24, Croatia
• Scientific / art field, discipline and subdiscipline: BIOMEDICINE AND HEALTHCARE; Veterinary Medicine; Veterinary Public Health and Food Safety

Abstract

U radu je istražena dinamika rasta bakterije L. monocytogenes u kuhanom kravljem siru
tijekom pohrane na 4º i 13ºC kroz dvadesetosam dana. Sir korišten u pokusu inicijalno nije
sadržavao bakteriju L. monocytogenes. U uzorcima inokuliranima s 104 CFU/ml L.
monocytogenes, utvrdili smo da bakterija kontinuirano raste te je dvadesetosmog dana
pohrane na temperaturi od 4°C utvrdena u broju 2,25 log/cm2, odnosno 2,35 log/cm2 u drugoj
skupini uzoraka držanih na temperaturi od 13°C. Medutim, dinamika rasta bakterije L.
monocytogenes nije pokazivala izrazite razlike ovisno o temperaturi pohrane sira, te je razlika
imedu najviših vrijednosti iznosila 0,10 log/cm2 zadnjeg dana pohrane uzoraka.
Ovo je istraživanje pokazalo da bakterija L. monocytogenes može rasti u kuhanom kravljem
siru, te da je prisutna u siru i nakon dvadeset osam dana pohrane u hladnjaku i na povišenoj
temperaturi. To je cini potencijalnom opasnošcu po zdravlje ljudi i u slucaju kada je pravilno
cuvana do isteka roka trajanja.

Abstract (english)

In this study, the dynamics of bacterial growth in boiled cow chees during 28 day storage on
temperatures of 4°C and 13°C was examined. Cheese sample use in this study was initialy
negative on Listeria monocytogenes. In samples inoculated with 104 CFU/ml, growth of L.
monocytogenes was observed during 28 days of storage on both temperatures. The number of
bacteria at day 28 ranged 2,25 log/cm2 at 4°C, while at 13 °C it was 2,35 log/cm2. However,
the dynamics of bacterial growth didn't show distinct differences depending on temeprature of
storage of the cheese, and difference on the last day of the study was 0,10 log/cm2 highest at
13°C.
Our experiment has shown that L. monocytogenes can grown in boiled cow cheese, and after
28th days of storage on refridgerator (+4°C) and abusive (+13°C) temperature. That makes
Listeria monocytogenes potential threat to human health, although the food is properly stored
until the expiry date.

• Keywords: Listeria monocytogenes; ucestalost nalaza; kriterij sigurnosti hrane
• Keywords (english): Listeria monocytogenes; prevalence; food safety objective
• Language: croatian
• URN:NBN: urn:nbn:hr:178:246554
• Study programme: Title: Veterinary Medicine; Study programme type: university; Study level: integrated undergraduate and graduate; Academic / professional title: doktor/doktorica veterinarske medicine (doktor/doktorica veterinarske medicine)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Access restricted to students and staff of home institution
• Created on: 2016-01-14 10:28:45