ta je zagaivanje, koji su tipovi zagaivanja, 邸ta su polutanti. Interaktivna prezentacija sa ukr邸tenicom, asocijacijom i zadacima koji e uenicima odr転ati pa転nju i aktivnost.
The document discusses pH and its impact on microorganisms. It defines pH as the negative logarithm of hydrogen ion concentration and describes the pH scale. It provides examples of the optimal and tolerated pH ranges for various bacteria, and discusses how pH affects the growth and development of different groups of microorganisms in foods. It also gives approximate pH values of various foods and explains how other environmental factors can interact with pH to impact microorganism growth.
15.uticaj procesnih parametara na rast i razmno転avanjeMaja Andjelkovic
油
Temperature is a key process factor that affects microbial growth and reproduction in foods. Microorganisms have three cardinal temperatures - minimum, optimum, and maximum temperatures - for growth. The optimum temperature for the growth of most pathogenic and spoilage microorganisms in foods is around 30属C.
The document discusses various extrinsic environmental factors that affect the growth of microorganisms, with a focus on temperature. It describes how microorganisms can be classified based on their optimal temperature ranges for growth, including psychrophiles, mesophiles, and thermophiles. The effects of temperature on microbial physiology and metabolism are explored, as well as its implications for food storage and safety.
Redox potential (Eh) is a physicochemical concept that reflects the ratio of oxidized and reduced forms of metabolites in a substrate. It acts selectively on the development of microorganisms in foods. Eh is expressed as a Eh-value, which is actually a measure of the oxidizing or reducing power of a chemical system. Reductions and oxidations are inseparable processes based on the transfer of electrons from one material to another. Materials that easily release electrons are good reducing agents, and those that easily accept electrons are good oxidizing agents. The redox potential of a substrate depends on pH, chemical composition, presence and mutual relationship of reductive (SH groups of proteins, hydrogen sulfide, ascorbic acid
The document discusses water activity (aw), which is an important factor that determines the development of microorganisms. aw represents the available water content in a substrate that microorganisms can use for their metabolic activity. It is defined as the ratio between the equilibrium vapor pressure of water in a food and the vapor pressure of saturated water vapor at the same temperature. aw values range from 0-1 and influence the growth and toxin production of various microorganisms. Foods are categorized based on their aw values as high, intermediate, or low moisture foods.
The document discusses pH and its impact on microorganisms. It defines pH as the negative logarithm of hydrogen ion concentration and describes the pH scale. It provides examples of the optimal and tolerated pH ranges for various bacteria, and discusses how pH affects the growth and development of different groups of microorganisms in foods. It also gives approximate pH values of various foods, meats, seafoods, and dairy products.
This document discusses nutrient utilization and microbial growth. It summarizes that microorganisms require nutrient-rich mediums containing amino acids and vitamins for growth. Milk contains low levels of free amino acids and peptides, so microbes have developed complex proteolytic systems to break down milk proteins into usable peptides and amino acids. These systems include extracellular proteinases and intracellular peptidases that hydrolyze proteins and peptides. The proteolytic system allows microbes to obtain essential amino acids needed for growth.
This document discusses the nutrients and conditions needed for the growth of microorganisms in foods. It notes that microbes break down proteins, fats, and carbohydrates in foods and can produce beneficial or harmful compounds. Under favorable conditions like sufficient nutrients and proper storage, microbe populations can increase exponentially to 107 cells/g within 8 hours. Controlling intrinsic factors such as pH, water activity, and antimicrobial components is important for microbiological control of foods.
The document discusses pH and its impact on microorganisms. It defines pH as the negative logarithm of hydrogen ion concentration and describes the pH scale. It provides examples of the optimal and tolerated pH ranges for various bacteria, and discusses how pH affects the growth and development of different groups of microorganisms in foods. It also gives approximate pH values of various foods and explains how other environmental factors can interact with pH to impact microorganism growth.
15.uticaj procesnih parametara na rast i razmno転avanjeMaja Andjelkovic
油
Temperature is a key process factor that affects microbial growth and reproduction in foods. Microorganisms have three cardinal temperatures - minimum, optimum, and maximum temperatures - for growth. The optimum temperature for the growth of most pathogenic and spoilage microorganisms in foods is around 30属C.
The document discusses various extrinsic environmental factors that affect the growth of microorganisms, with a focus on temperature. It describes how microorganisms can be classified based on their optimal temperature ranges for growth, including psychrophiles, mesophiles, and thermophiles. The effects of temperature on microbial physiology and metabolism are explored, as well as its implications for food storage and safety.
Redox potential (Eh) is a physicochemical concept that reflects the ratio of oxidized and reduced forms of metabolites in a substrate. It acts selectively on the development of microorganisms in foods. Eh is expressed as a Eh-value, which is actually a measure of the oxidizing or reducing power of a chemical system. Reductions and oxidations are inseparable processes based on the transfer of electrons from one material to another. Materials that easily release electrons are good reducing agents, and those that easily accept electrons are good oxidizing agents. The redox potential of a substrate depends on pH, chemical composition, presence and mutual relationship of reductive (SH groups of proteins, hydrogen sulfide, ascorbic acid
The document discusses water activity (aw), which is an important factor that determines the development of microorganisms. aw represents the available water content in a substrate that microorganisms can use for their metabolic activity. It is defined as the ratio between the equilibrium vapor pressure of water in a food and the vapor pressure of saturated water vapor at the same temperature. aw values range from 0-1 and influence the growth and toxin production of various microorganisms. Foods are categorized based on their aw values as high, intermediate, or low moisture foods.
The document discusses pH and its impact on microorganisms. It defines pH as the negative logarithm of hydrogen ion concentration and describes the pH scale. It provides examples of the optimal and tolerated pH ranges for various bacteria, and discusses how pH affects the growth and development of different groups of microorganisms in foods. It also gives approximate pH values of various foods, meats, seafoods, and dairy products.
This document discusses nutrient utilization and microbial growth. It summarizes that microorganisms require nutrient-rich mediums containing amino acids and vitamins for growth. Milk contains low levels of free amino acids and peptides, so microbes have developed complex proteolytic systems to break down milk proteins into usable peptides and amino acids. These systems include extracellular proteinases and intracellular peptidases that hydrolyze proteins and peptides. The proteolytic system allows microbes to obtain essential amino acids needed for growth.
This document discusses the nutrients and conditions needed for the growth of microorganisms in foods. It notes that microbes break down proteins, fats, and carbohydrates in foods and can produce beneficial or harmful compounds. Under favorable conditions like sufficient nutrients and proper storage, microbe populations can increase exponentially to 107 cells/g within 8 hours. Controlling intrinsic factors such as pH, water activity, and antimicrobial components is important for microbiological control of foods.
1. KATEDRA ZA HIGIJENU I TEHNOLOGIJU NAMIRNICA ANIMALNOG POREKLA
FAKULTET VETERINARSKE MEDICINE UNIVERZITET U BEOGRADU
Uticaj procesnih faktora u proizvodnji
namirnica na razvoj zajednice
mikroorganizama
RELATIVNA VLA貼NOST
Pripremio: Neeljko Karabasil
MIKROBIOLOGIJA NAMIRNICA
2. KATEDRA ZA HIGIJENU I TEHNOLOGIJU NAMIRNICA ANIMALNOG POREKLA
FAKULTET VETERINARSKE MEDICINE UNIVERZITET U BEOGRADU
FAKTORI KOJI UTIU NA RAST MIKROORGANIZAMA
EKSTRI貼IN faktori
INTRI貼IN faktori - temperatura
- pH - relativna vla転nost
- aw
- prisustvo i
-hranljive materije
koncentracija gasova
-antimikrobne komponenete
-biolo邸ke strukture - prisustvo i aktivnost
ostalih mikroorganizama
MIKROBIOLOGIJA NAMIRNICA
3. KATEDRA ZA HIGIJENU I TEHNOLOGIJU NAMIRNICA ANIMALNOG POREKLA
FAKULTET VETERINARSKE MEDICINE UNIVERZITET U BEOGRADU
DEFINICIJA...
VODA se mo転e nai u tri agregatna stanja
- tenom...voda
- vrstom...led
- gasovitom...vodena para
- me邸avina...vla転an vazduh ...vazduh
VLA貼NOST
- RELATIVNA VLA貼NOST
- APSOLUTNA VLA貼NOST (masa vodene pare sadr転ana u zapremini vazduha, kg/m3)
- SPECIFINA VLA貼NOST (koliina vodene pare po kilogramu vla転nog vazduha)
MIKROBIOLOGIJA NAMIRNICA
4. KATEDRA ZA HIGIJENU I TEHNOLOGIJU NAMIRNICA ANIMALNOG POREKLA
FAKULTET VETERINARSKE MEDICINE UNIVERZITET U BEOGRADU
DEFINICIJA...
Relativna vla転nost je termin kojim opisujemo koliinu vodene
pare u me邸avini vazduha i vode
aw
P
FORMULA RH = 100 x
Po
Relativna vla転nost je mera kojom se ukazuje na koliinu vodene
pare u vazduhu (pri odreenoj temperaturi) [P] u odnosu na
maksimalnu koliinu vodene pare koju vazduh mo転e da primi pri
toj temperaturi [Po] i izra転ava se u procentima.
MIKROBIOLOGIJA NAMIRNICA
5. KATEDRA ZA HIGIJENU I TEHNOLOGIJU NAMIRNICA ANIMALNOG POREKLA
FAKULTET VETERINARSKE MEDICINE UNIVERZITET U BEOGRADU
DEFINICIJA...
Relativna vla転nost zavisi od temperature vazduha
Topao vazduh mo転e da primi vi邸e vodene pare nego
hladan vazduh.
PRIMER 1. Relativna vla転nost od 100 % ukazuje da vazduh
sadr転i maksimalnu koliinu vode pri datoj temperaturi, a svaka
koliina dodatne vlage rezultirae kondenzacijom.
PRIMER 2. Ako je relativna vla転nost 50 %, to ukazuje da
vazduh sadr転i polovinu koliine vodene pare koju mo転e da primi
pri datoj temperaturi. Kako temperatura vazduha pada, koliina
vlage u vazduhu se menja i relativna vla転nost raste (po邸to koliina
vlage koju hladan vazduh mo転e da dr転i je manja)
MIKROBIOLOGIJA NAMIRNICA
6. KATEDRA ZA HIGIJENU I TEHNOLOGIJU NAMIRNICA ANIMALNOG POREKLA
FAKULTET VETERINARSKE MEDICINE UNIVERZITET U BEOGRADU
DEFINICIJA...
Trend RELATIVNA VLA貼NOST - TEMPERATURA
Relativna vla転nost
TEMPERATURA
VLA貼NOST
Temperatura
MIKROBIOLOGIJA NAMIRNICA
7. KATEDRA ZA HIGIJENU I TEHNOLOGIJU NAMIRNICA
FAKULTET VETERINARSKE MEDICINE UNIVERZITET U BEOGRADU
Znaaj RH kao faktora sredine
uslovi skladi邸tenja
aw (povr邸ine i dubljih delova matriksa)
Temperatura
rast mikroorganizama na povr邸ini proizvoda
MIKROBIOLOGIJA NAMIRNICA
8. KATEDRA ZA HIGIJENU I TEHNOLOGIJU NAMIRNICA
FAKULTET VETERINARSKE MEDICINE UNIVERZITET U BEOGRADU
Znaaj RH kao faktora sredine
uslovi skladi邸tenja
1
RH
aw
Primer 1. RH 2
Niska aw vrednost proizvoda + visok %
Primer 2.
RH (uslovi skladi邸tenja) = adsorpcija
vode namirnicom Visoka aw vrednost proizvoda + nizak %
RH (uslovi skladi邸tenja)= desorpcija
vode/isparavanje iz namirnice
Do postizanja RAVNOTE貼E AW = RV
MIKROBIOLOGIJA NAMIRNICA
9. KATEDRA ZA HIGIJENU I TEHNOLOGIJU NAMIRNICA
FAKULTET VETERINARSKE MEDICINE UNIVERZITET U BEOGRADU
Znaaj RH kao faktora sredine
uslovi skladi邸tenja
T
aw
CIRKULACIJA VAZDUHA
aw
RH
MIKROBIOLOGIJA NAMIRNICA
10. KATEDRA ZA HIGIJENU I TEHNOLOGIJU NAMIRNICA
FAKULTET VETERINARSKE MEDICINE UNIVERZITET U BEOGRADU
Znaaj RH kao faktora sredine
TAKA ROSE je ona temperatura pri kojoj vazduh prilikom
hlaenja postaje zasien i u tom trenutku poinje izdvajanje
magle ili rose na povr邸inama (namirnica!!!)...
Stimuli邸e razvoj mikroorganizama
Taka rose zavisi od tri vrednosti:
BAKTERIJE KVARA
T vazduha Zahtevaju visoku aw
Pseudomonas
Acinetobacter
RH
Moraxella
Mogu se razmno転avati i pri
T proizvoda ni転im vrednostima aw
bacili, kvasci, plesni
MIKROBIOLOGIJA NAMIRNICA
![KATEDRA ZA HIGIJENU I TEHNOLOGIJU NAMIRNICA ANIMALNOG POREKLA
FAKULTET VETERINARSKE MEDICINE UNIVERZITET U BEOGRADU
DEFINICIJA...
Relativna vla転nost je termin kojim opisujemo koliinu vodene
pare u me邸avini vazduha i vode
aw
P
FORMULA RH = 100 x
Po
Relativna vla転nost je mera kojom se ukazuje na koliinu vodene
pare u vazduhu (pri odreenoj temperaturi) [P] u odnosu na
maksimalnu koliinu vodene pare koju vazduh mo転e da primi pri
toj temperaturi [Po] i izra転ava se u procentima.
MIKROBIOLOGIJA NAMIRNICA](https://image.slidesharecdn.com/13-2007relativnavlaznost-120629155309-phpapp01/85/13-predavanje-relativna-vlaznost-4-320.jpg)
