Lab 11 Flashcards
(20 cards)
What are the 5 conditions for spoilage?
-water
-pH
-Physical structure
-oxygen
-temperature
what are Intrinsic factors?
composition, physical and biological state
what is Intrinsic composition?
Putrefaction Proteolysis and anaerobic breakdown of proteins, yielding foul-smelling amine compounds Cadaverine
what is the Physical structure of Intrinsic
grinding and mixing increase surface area and distribute microbes promotes microbial growth
what are Extrinsic Factors?
Includes temperature, relative humidity, gases, contaminating microorganisms.
what is the adequate temperature?
lower temperature delay microbial growth
Gases
atmosphere where oxygen promotes growth. -shrink wrap to package food in controlled atmospheres.
Relative humidity
high levels promote microbial growth
Osmophilic
prefer high osmotic pressure
Xerophilic:
prefer lower water activity
what does lower water activity lead to?
less microbial growth
What leads to lower water activity ?
salt and sugar
Food borne infection
microbes are transferred to consumer
Food intoxication
results from the toxin consumption in foods in which microbes have grown.
What is fermentation?
partial breakdown of carbohydrates taking place in the absence of oxygen
examples of fermentation-
Lactic- Dairy products such as : cheese, buttermilk, kefir, yogurt
Propionic- Fermented foods
Ethanol- Alcoholic beverage
What are the 3 methods for detection of food borne pathogens
Culture techniques
-Immunological techniques
-Molecular techniques
what is Culture techniques
too slow
what are Immunological techniques
very sensitive
what are Molecular techniques
sensitive and specific
