Food Microbiology Test assessment
and answers graded A+
What are microbes? - ANS✅✅microscopic organisms
Most important microbes associated with food: - ANS✅✅- Viruses (0.1 micrometers)
- Bacteria (1 micrometer)
- Yeasts (10 micrometers)
- Molds (100 micrometers)
- Parasites (varying sizes)
Parasites - ANS✅✅- found in raw and undercooked foods
- seafood, meat, vegetables
- also transmitted by water, soil, or person-person contact
- e.g. poor hygiene or unsanitary facilities among food service workers
Viruses - ANS✅✅- food is a transportation medium between hosts
- do not multiply in food; reran in food that is under- or not cooked
Norovirus:
- leading cause if gastroenteritis, the stomach flu
Hepatitis A:
- causes liver disease
- spread primarily through contaminated food or water
- raw shellfish are a source
- can be prevented by vaccination
Molds - ANS✅✅- grow in a tangled mass of mycelium
- molds replicated by spores caller conidia, visible at the top of the hyphae
- spores are dispersed through the air
, Molds (Fungi) - ANS✅✅- many molds are spoilage organism's
- some molds contribute character to cheeses (blue cheese) & fermentations (soy sauce)
- not known to cause gastrointestinal distress but some molds cause allergic reactions, respiratory
problems and/or long term health consequences
- some molds on crops and foodstuffs produce "mycotoxins" (poisonous substances causing illness,
e.g. aspergillum spp.)
Rhizioids (molds, cont.) - ANS✅✅Root-like structures that anchor mold to a food
- trim about 2cm from the top of cheese or firm fruits and vegetables to avoid consuming mold
rhizoids
Yeasts (Fungi) - ANS✅✅- yeast can be spoilage organisms (fruit & juices, yogurt, mayonnaise)
- yeasts perform food fermentation (starter cultures in bread, wine, beer, and other alcoholic
fermentations)
Bacteria - ANS✅✅Primary organisms implicated in foodbourne disease (on their own or their
toxins)
- salmonella spp, clostridium botulinum (toxin is very difficult to destroy; forms spores),
Staphylococcus aureus
Bacteria beneficial effects - ANS✅✅- Probiotics: bacteria with health benefits
- Fermentations (lactic acid bacteria)
Vegetative bacteria produce spores in unfavourable conditions - ANS✅✅- spores develop in
response to unfavourable growth conditions
- vegetative bacteria die while spores are 'pseudo dormant' (period in an organism's life cycle when
growth, development, and physical activity are temporarily stopped)
- spores germinate into vegetative states when favourable conditions return
What are implications of spores in food products? - ANS✅✅- spores have greater resistance to
heating drying and irradiation processing than bacteria
- many spores are thermoduric (bacteria resistant to heat treatment at high temperatures.) and acid
resistance
and answers graded A+
What are microbes? - ANS✅✅microscopic organisms
Most important microbes associated with food: - ANS✅✅- Viruses (0.1 micrometers)
- Bacteria (1 micrometer)
- Yeasts (10 micrometers)
- Molds (100 micrometers)
- Parasites (varying sizes)
Parasites - ANS✅✅- found in raw and undercooked foods
- seafood, meat, vegetables
- also transmitted by water, soil, or person-person contact
- e.g. poor hygiene or unsanitary facilities among food service workers
Viruses - ANS✅✅- food is a transportation medium between hosts
- do not multiply in food; reran in food that is under- or not cooked
Norovirus:
- leading cause if gastroenteritis, the stomach flu
Hepatitis A:
- causes liver disease
- spread primarily through contaminated food or water
- raw shellfish are a source
- can be prevented by vaccination
Molds - ANS✅✅- grow in a tangled mass of mycelium
- molds replicated by spores caller conidia, visible at the top of the hyphae
- spores are dispersed through the air
, Molds (Fungi) - ANS✅✅- many molds are spoilage organism's
- some molds contribute character to cheeses (blue cheese) & fermentations (soy sauce)
- not known to cause gastrointestinal distress but some molds cause allergic reactions, respiratory
problems and/or long term health consequences
- some molds on crops and foodstuffs produce "mycotoxins" (poisonous substances causing illness,
e.g. aspergillum spp.)
Rhizioids (molds, cont.) - ANS✅✅Root-like structures that anchor mold to a food
- trim about 2cm from the top of cheese or firm fruits and vegetables to avoid consuming mold
rhizoids
Yeasts (Fungi) - ANS✅✅- yeast can be spoilage organisms (fruit & juices, yogurt, mayonnaise)
- yeasts perform food fermentation (starter cultures in bread, wine, beer, and other alcoholic
fermentations)
Bacteria - ANS✅✅Primary organisms implicated in foodbourne disease (on their own or their
toxins)
- salmonella spp, clostridium botulinum (toxin is very difficult to destroy; forms spores),
Staphylococcus aureus
Bacteria beneficial effects - ANS✅✅- Probiotics: bacteria with health benefits
- Fermentations (lactic acid bacteria)
Vegetative bacteria produce spores in unfavourable conditions - ANS✅✅- spores develop in
response to unfavourable growth conditions
- vegetative bacteria die while spores are 'pseudo dormant' (period in an organism's life cycle when
growth, development, and physical activity are temporarily stopped)
- spores germinate into vegetative states when favourable conditions return
What are implications of spores in food products? - ANS✅✅- spores have greater resistance to
heating drying and irradiation processing than bacteria
- many spores are thermoduric (bacteria resistant to heat treatment at high temperatures.) and acid
resistance
