363 MT1 Material Exam Study Guide.
Food Supply - answerEconomics (cost of food supply)
Convenience
Nutrition and health
Consumer Acceptance (shelf space, new foods)
Safety
Economics - answerLow cost of food supply
Less time spent preparing food
Compared to northern or 3rd world countries
C...
Food Supply - answer✔Economics (cost of food supply)
Convenience
Nutrition and health
Consumer Acceptance (shelf space, new foods)
Safety
Economics - answer✔Low cost of food supply
Less time spent preparing food
Compared to northern or 3rd world countries
Convenience - answer✔Food supply is made for convenience
Tech advances allow us to keep ready to eat foods for days
More ready to eat/ take out
Nutrition and Health - answer✔Processes foods are highly regulated *if they take a nutrient out
they must put it back)
Fractionated foods: how many steps and ingredients a food goes through
Functional foods: produced to achieve additional benefits
Consumer Acceptance - answer✔Shelf space is at a prime
Large number of foods introduced
Safety - answer✔Foods expected to be safe
Systems in place to reduce risk
Illness due to mistakes at some level
Moving Target of Food Supply - answer✔Change in consumer demographoc
New emerging tech
Changes in agriculture, climate change
Evolution of bacterua
Hazards in Food Supply - answer✔From greatest to least risk
- Microbiological
- Nutritional concerns
- environmental contamination
-natural toxins, pesticide residues, additives
Regulation of Food Supply - answer✔Food and Drug act and regulations (policy)
Canadian food inspection agency - CFIA (enforcement)
Food Microbiology history - answer✔Started in middle east
WIne, beer, bread
Raw materials and tech were available
Domesticated grains were known but not grown at large scale bc cultivation was a high risk
strat for survival
Agriculture - answer✔Made it available to sustain a alarge pop
^ pop ^ pathogen evolution
Easier spread of disease
Food Preservation Scientists - answer✔Appert: heat sterilized food for ^ shelf life
Pasteur: fermentation of wine, milk bacteria
Koch: diseases from contaminated water
Lister: LAB, concept of antiseptic
Escherich: ecoli
Taxonomy - answer✔A microbial species have a common set or pattern of correlating stable
properties
Compare AA sequence to try and infer relationships but is imprecise
SHare over 98.7% sequence identity on a full length of 16S rRNA gene type strain
Also depends on other criteria
Bacteria taxonomy Methods - answer✔1. DNA-DNA hybridization: 70% similiarity is cut off (if
they share similar dna they will hybridize)
2. Marker genes: conserved in sequence and fxn but have sufficient variability btwn species
- ribosomal rna: use one gene for species identification (simple, cheap, limited resolution)
3. Average Nucleotide Identity (ANI) btwn 2 species: requires genome sequence and describes
genetic relatedness
Sources of Microorganisms in Food - answer✔Plants & animals harbour commensal microbiota
Microbes colonize food processing facilities
Humans harbour microbes that are trabsfered during food handling
Contamination during slaughter
Heat processed foods have low CFU - post process contam
Fermented foods are inoculated w high cell counts of started cultures
Bacteria that Prevails in Food - answer✔Most are chemoheterotrophs (utilize aas, sugars in
food for ATP)
Have complex nutiritional reqs (specific environments)
Have a specific growth range and a specific survivial range (moisture, pH, temp)
Microbiotal Growth Curve - answer✔Lag phase: time needed to adapt and reroute metabolism
for growth
Exponential growth phase: double/divide every few mins-h
(generation t= t for one cell to double - reflection of how fast a culture will grow)
Stationary phase: may start to die off as nutrients are exhausted
Death
Rate of Growth - answer✔Determines how fast food will spoil or ferment
Determines whether a pathogenic bacteria will grow and produce toxins
Control Mechs - answer✔Accelerate growth in fermentation
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