Methods of Measuring Growth Flashcards
True or false. The higher the OD, lesser light is absorbed.
False. The more the light is absorbed.
Reduces bacterial load
Serial dilution
Method in viable count in which culture and media are mixed
Pour-plate method (microaerophilic: reduced need for oxygen)
Medium used in 3rd phase of most probable no. technique
Eosin Methylene Blue (EMB)
Where to get samples for most probable no. technique
Water, food, air
Three phases in most probable no. technique
Presumptive, confirmatory, completed
Downside of direct cell count
Reveal higher no. compared to viable as it considers both dead and alive (great plate count anomaly)
Medium used in 1st phase of most probable no. technique
Lauryl Sulfate Tryptone Broth (LSTB)
Optical density measures
the amount of light unscattered
Durham tubes are used to
Check turbidity
The standard range in serial dilution
30 - 300
No. of cells in grids in counted
Direct cell count
What is measured in spectrophotometer?
Optical density (OD)
Downside of spread-plate method
Affected by the environment
Method in viable count in which agar is in plate already
Spread-plate method
In direct cell counting, sample is placed into a?
Petroff-Hauser counting chamber (haemocytometer)
Downside of serial dilution
Tedious process
Solution for great plate count anomaly
Use highly selective media (depending on goal), vary culture conditions
Advantage and disadvantage of spectrophotomerer
ADV: Quick (~10 mins.)
DIS: Counts dead cells
Basis for results of most probable no. technique
Gas production, turbidity
Types of diluent
NSS, PBS
True or false. Colony growth on plate reflects no. of cells in sample.
True
Use of membrane filters w/ specific pores
Filtration
Medium used in 2nd phase of most probable no. technique
Brilliant Green Lactose Bile Broth (BGLB) [45 deg. C, 24H, turbidity]
