Quantify Bacteria

Question 1

Direct Count

Answer 1

counting every cell under microscope

Question 2

Turbidometric method Spechophotometer

Answer 2

To measure light absorbance optical density (O.D.). Most typical; H2O for e.coli food setting. High OD, turban cloudy. The higher the OD higher cell number. 1:1000 2:2000

Question 3

Standard plate count

Answer 3

Count colonies on agar plate. Colony forming units. CFU/mL

Question 4

Bacterophage

Answer 4

non cell is a virus for bacteria.

Question 5

Plate assay

Answer 5

count plaque no colonies

Question 6

Count Plaque (how it looks)

Answer 6

Clear spots with no bacterial colonies present. Write results with PFU/nO at the end

Question 7

Plague forming unit

Answer 7

PFU/mL

Question 8

Colony Forming Unit

Answer 8

CFU/mL

Question 9

Standard Plate Count Quantification

Answer 9

Determines a series of dilution that will give the required dilution factors ON AN AGAR PLATE. You may use 9ml or 99 ml diluents.

Question 10

How does plaque shows

Answer 10

A plaque is a blank spot.

Question 11

How many colonies/plaques can you count

Answer 11

30-300

Question 12

plate count procedure

Answer 12

mix sample gently. use hockey stick to spread bacteria. untouch for 15 min. leave them at room temp for 2 days.

Question 13

Why is necessary to dilute sample

Answer 13

To decrease the bacterial population to a required concentration.

Question 14

Sources of error

Answer 14

x Not using aseptic technique

x Not using the clam method