OLEARY L4 Fungi Flashcards
Process of fungi in food production?
- Yeast (Saccharomyces cerevisiae) converts glucose to alcohol
glucose - 2 pyruvate - 2 acetylaldehyde - 2 ethanol
What is the yeast conversion of glucose to alcohol called?
Fermentation
What is the stirrer used for?
To keep the microorganisms, nutrients and temperature evenly distributed
What are probiotics?
Live microorganisms that when administered in adequate amounts, confer a health benefit on the host
What are examples of beneficial probiotic strains?
-Lactobacillus acidophiles
-Bifidobacterium longum
What are bacterial spoilage effects?
-Texture/taste
-Gas/swollen packaging and cxans
-Off odours
-Slime
Fungal spoilage?
-Moulds visible
-Texture/ structure
-Off odours or flavours
-Gas
What are the conditions needed for bacterial growth?
FATTOM
Food - prefer high protein foods like meat, dairy products, cooked veg
Acidity - pH between 4.6-7.6 for growth
Temp - danger zone is 41-135 degrees
Oxygen
Moisture/water
What displaces oxygen?
nitrogen gas
What is a foodborne illness?
Any illness arising from the consumption of contaminated food
What are some features of P.expansum and A.flavus?
-2 major food spoilage fungi
-No active spore dispersal mechanism
-2-3um spores act like fine dust carried by air turbulence
-Unwettable, resist dessication and UV radiation
What are some features of Fusarium graminearum?
-Major plant pathogen
-Wettable - dispersed by rain droplet impact
Which fungi twist and collapse ejecting spores as humidity increases?
Cladosporium
Which fungi fire ballistospores into the air as humidity increases at hight hours?
Mirror yeast
Features of moulds?
Exist as multicellular, filamentous colonies
-Favour solid surfaces
-Mostly asexual spores
-Aerobic or faculative anaerobes
Features of yeasts?
-Exist as unicellular, filamentous colonies
-Favour liquid environments
-Mostly sexual reproduction
-Aerobic or faculative anaerobes
-Dimorphic can exist as mould or yeast e.g penicillium marneffei
What is an example of a dimorphic fungi?
Penicillium marneffei
Do moulds grow well in low nutrient environments?
Yes they are much less fastidious than bacteria
What is the dgeree of aw tolerance?
The minimum level at which germination and growth can occur
What are moulds usually - temp wise - what moulds can grow at a high or low temp
Most moulds are mesophilic
-Cladosporium can grow at -7 (also fusarium, penicillium)
Aspergillus can grow up to 60 degrees
