master's thesis
Mikrobiološka kvaliteta mlijeka u proizvodnji sira od sirovog mlijeka

Vlatka Zebec (2016)
Sveučilište u Zagrebu
Agronomski fakultet
Opće stočarstvo
Metadata
TitleMikrobiološka kvaliteta mlijeka u proizvodnji sira od sirovog mlijeka
AuthorVlatka Zebec
Mentor(s)Dubravka Samaržija (thesis advisor)
Abstract
U radu su na temelju dosadašnjih istraživanja prikazani znanstveni rezultati istraživanja mikrobiološke kvalitete sirovog mlijeka i sira na primjeru Paškog, Krčkog i Domiati sira. Paški i Krčki sir su najpoznatiji tvrdi ovčji sirevi u Hrvatskoj, a Domiati je bijeli meki sir koji zrije u salamuri, veoma popularan u Egiptu i zemljama Bliskog Istoka. U proizvodnji većine tradicionalnih sireva koristi se sirovo mlijeko koje može biti izvor patogenih bakterija i mikroorganizama uzročnika kvarenja. Stoga je poznavanje izvora kontaminacije, načina njihovog rasta u mlijeku i njihovog uništenja presudno za dobivanje zdravstveno ispravnog sira. Učinkovita metoda za kontrolu rasta mikroorganizama je primjena HACCP sustava u proizvodnom postrojenju i primjena načela dobre proizvođačke, poljoprivredne i veterinarske prakse u primarnoj proizvodnji mlijeka. Tijekom pokusnog razdoblja prosječni broj somatskih stanica u ovčjem mlijeku (n=15) koje se koristilo u proizvodnji Krčkog sira (n=9) bio je 407 000 mL-1, a ukupan broj bakterija 750 500 cfu mL-1. U ovčjem mlijeku koje se koristilo u proizvodnji Paškog sira tijekom pokusnog razdobljaod tri godine utvrđeni prosječni broj somatskih stanica bio je manji od 200 000 mL-1 a ukupni broj bakterija manji od 5000 cfu mL-1 (n=720). Na temelju rezultata higijenske kvalitete mlijeka i jedno i drugo ovčje mlijeko ispunjava propisane kriterije Pravilnika (NN 102/00). Rezultati mikrobioloških analiza na pojavnost patogenih bakterija u Paškom siru (n=240) tijekom trogodišnjeg praćenja bili su negativni te su u potpunosti sukladni odredbama Pravilnika o mikrobiološki kriterijima za hranu (NN 156/08). Suprotno, 45% uzoraka Krčkog sira u istraživanom razdoblju bilo je pozitivno na bakterije Staphylococcus aureus i Escherichia coli. Mikrobiološkim analizama kravljeg mlijeka (n=50) i Domiati sira (n=50) utvrđena je prisutnost patogenih bakterija iznad dozvoljenih granica propisanih Uredbom EZ 853/2004 i ES 1008/2000. U usporedbi s Paškim i Krčkim sirom Domiati sir je podložniji pojavnosti patogenih bakterija. Razlog tome je visoki postotak vlage i pH u sirnom tijestu i tehnologija proizvodnje u kojoj se koriste niske temperature obrade sirnog gruša i kratko trajanje zrenja.
Keywordshygienic quality sheep milk patogenic bacteria mikrobiological quality Paški cheese Krčki cheese Domiati cheese legislation
Committee MembersDubravka Samaržija (committee chairperson)
Sanja Sikora (committee member)
Samir Kalit (committee member)
GranterSveučilište u Zagrebu
Agronomski fakultet
Lower level organizational unitsOpće stočarstvo
PlaceZagreb
StateCroatia
Scientific field, discipline, subdisciplineBIOTECHNICAL SCIENCES
Agronomy
Dairy
Study programme typeuniversity
Study levelgraduate
Study programmeProduction and Processing of Milk
Academic title abbreviationmag. ing. agr.
Genremaster's thesis
Language Croatian
Defense date2016-03-22
Parallel abstract (English)
Reviewing previous scientific research results of microbiological quality of raw milk and Paški, Krčki and Domiati cheese are shown. Paški and Krčki cheese are famous Croatian hard sheep cheese, while Domiati cheese, which ripens in brine, is very popular in Egypt and Middle East countries. In the production of most traditional cheeses raw milk is used, which can be source of pathogenic bacteria and spoilage microorganisms. Therefore, knowledge of the origin, the way of their growth in milk and their destruction is crucial to obtain a safe cheese. An effective method to control growth of microorganisms is the application of the HACCP system in the production plant and the application of the principles of good manufacturing, agricultural and veterinary practices in the primary production of milk. During the experimental period the average number of somatic cells in the sheep's milk used in the manufacture of Krčki cheese was 407 000 mL-1 and the total bacterial count of 750 500 cfu mL-1. The sheep's milk used in the manufacture of Paški cheese during the experimental period of three years average number of somatic cells was less than 200,000 mL-1 and the total bacterial count of less than 5000 cfu mL-1 (n =720). Based on the results of hygienic quality of milk both sheep milks comply criteria prescribed by Pravilnik (NN 102/00).The results of microbiological analysis on the incidence of pathogenic bacteria in the Paški cheese (n=240) during the three-year period were negative, and are fully compliant with the provisions of the Regulation for microbiological criteria for food (NN156/08). In contrast, 45% samples of Krčki cheese in the investigation period were positive for Staphylococcus. aureus and Escherichia coli bacteria. Microbiological analyzes of cow's milk (n=50) and Domiati cheese (n=50) was found the presence of pathogenic bacteria over the allowable limit prescribed by Regulation EC 853/2004 and EC 1008/2000. Compared with the Paški and Krčki cheese, Domiati cheese is more susceptible on the incidence of pathogenic bacteria. The reason for this is the high percentage of moisture and higher pH value in cheese curdand specificity of production technology, which uses low-temperature processing of cheese curd and short duration of ripening.
Parallel keywords (Croatian)higijenska kvaliteta ovčje mlijeko patogene bakterije mikrobiološka kvaliteta Paški sir Krčki sir Domiati sir legislativa
Resource typetext
Access conditionOpen access
Terms of usehttp://rightsstatements.org/vocab/InC/1.0/
URN:NBNhttps://urn.nsk.hr/urn:nbn:hr:204:297272
CommitterValentina Bezek