undergraduate thesis
Milk pasteurization and sterilisation

Jurka Mašić (2010)
Josip Juraj Strossmayer University of Osijek
FACULTY OF FOOD TECHNOLOGY
Department of Food Technologies
Sub-department of Milk Technology
Metadata
TitleToplinski postupci obrade mlijeka
AuthorJurka Mašić
Mentor(s)Vedran Slačanac (thesis advisor)
Abstract
Mlijeko namijenjeno za konzumaciju mora biti pasterizirano ili sterilizirano. Pasterizacija je proces kojim se inaktiviraju glavne patogene bakterije i bakterije uzročnici kvarenja u sirovom mlijeku. Daljnje unaprjeđenje sigurnosti mlijeka postiže se pažljivom kontrolom postpasterizacijske kontaminacije (PPC), primjenom sirovog mlijeka dobre kvalitete i pažljivim upravljanjem uvjetima procesiranja. Međutim, preživljavanje i razvoj termorezistentnih bakterija ili bilo kakva postpasterizacijska kontaminacija dovodi do kvarenja mlijeka. Za očuvanje trajnosti mlijeka kroz duži period na sobnoj temperature potrebno je provesti sterilizaciju. Tradicionalni postupak uključuje zagrijavanje mlijeka u temperaturnom rasponu od 116 – 120 °C kroz 20 – 30 minuta. Danas se sve više primjenjuje UHT postupak. To je kontinuiran postupak sterilizacije pri kojem se primjenjuje temperatura do 150 °C. Najvažnija svrha termičkog tretmana je redukcija mikrobne populacije. Također dolazi do određenih kemijskih reakcija i promjena fizikalnih svojstva. Neke od važnih promjena su: promjena pH vrijednosti, precipitacija kalcij fosfata, prodiranje do proteina i interakcija sa kazeinom, Maillardovo posmeđivanje i tvorba kazeinskih micela. Dva najbitnija kinetička parametra su brzina reakcije inaktivacije pri konstantnoj temperaturi i utjecaj promjene temperature na brzinu reakcije. Termorezistentnost vegetativnih i sporogenih bakterija pri konstantnoj temperaturi je karakteriziana vremenom decimalne redukcije (D), to je vrijeme potrebno za redukciju 90% mikrobne populacije ili jedna decimalna redukcija.
Keywordsmilk pasteurization sterilization
Parallel title (English)Milk pasteurization and sterilisation
GranterJosip Juraj Strossmayer University of Osijek
FACULTY OF FOOD TECHNOLOGY
Lower level organizational unitsDepartment of Food Technologies
Sub-department of Milk Technology
PlaceOsijek
StateCroatia
Scientific field, discipline, subdisciplineBIOTECHNICAL SCIENCES
Food Technology
Engineering
Study programme typeuniversity
Study levelundergraduate
Study programmeFood Technology
Academic title abbreviationuniv. bacc. ing. techn. aliment.
Genreundergraduate thesis
Language Croatian
Defense date2010-06-11
Parallel abstract (English)
Liquid milk for consumption is mostly either pasteurized or sterilized. Pasteurization is a milk process, designed to inactive the major pathogenic and spoilage bacteria in a raw milk. Further improvements in shelf-life can be obtained by careful control of postpasteurization contamination (PPC), by use of good quality raw milk and carefully manipulations of the processing conditions. However due to survival and growth of thermouric bacteria or any post-pasteurization contaminants milk will spoil. To keep milk longer then few days at ambient temperature, it needs to be sterilized. The traditional process involves heated milk in the temperature range 114 – 120 Celsius degree for 20 – 30 minutes. More recently UHT process has been introduced. These are continuous sterilization process and involve temperatures in excess of 150 Celsius degree. One of the main purposes of heat treatment is to reduce the microbial population in raw milk. Also, chemical reactions take place and there are changes in physical properties. Some important changes are decrease in pH, precipitation of calcium phosphate, penetration of whey proteins and interaction with casein, Mallard brewing and modifications to the casein micelle. The two most important kinetic parameters are the rate of reaction of inactivation at a constant temperature and the effect of temperature change on reaction rate. The heat resistance of vegetative bacteria and microbial spores at a constant temperatures is characterized by their decimal reduction time (D), this is the time required to reduce the population of 90% or one decimal reduction.
Parallel keywords (Croatian)mlijeko pasterizacija sterilizacija
Resource typetext
Access conditionAccess restricted to students and staff of home institution
Terms of usehttp://rightsstatements.org/vocab/InC/1.0/
URN:NBNhttps://urn.nsk.hr/urn:nbn:hr:109:264202
CommitterIvana Šuvak