Bacte LAB Agar prep, QC

Question 1

• Contains nutrients needed by microorganism to grow
• Widely employed for isolation, identification and sensitivity testing of different pathogenic microorganism
• Selection of culture media is based on the nutritional need of the microorganism of interest

Answer 1

Culture Media

Question 2

microorganisms with special nutritional/environmental requirement

Answer 2

Fastidious

Question 3

microorganism that require only basic nutritional/environmental requirements

Answer 3

Nonfastidious

Question 4

Classification of Culture Media

Based on Consistency:

Answer 4

1. Liquid media
2. Semi-solid media
3. Solid media
4. Biphasic media

Question 5

Classification of Culture Media

Based on Use:

Answer 5

1. Simple Media (general purpose/Supportive)

2.Enriched Media

3. Enrichment Media
4. Selective Media
5. Differential Media

Question 6

Simple Media (general purpose/Supportive) example

Answer 6

Nutrient Agar

Question 7

Enriched Media example

Answer 7

Blood Agar Plate

Question 8

Enrichment Media example

Answer 8

Thioglycolate broth

Question 9

Selective Media example

Answer 9

MacConkey Agar

Question 10

Differential Media

Answer 10

Hektoen Enteric Agar

Question 11

Tubes for Biochemical Test

Answer 11

Butt - SIM

Slant - Citrate

Butt-slant - LIA and TSI

Question 12

Parameters of water to be checked: presence of copper ions, conductivity and pH

• Petri dishes should be checked for residual EtO toxicity (MPL – 1ug/g; GC method)
• Borosilicate glassware should be used (Soda glass can leach alkali in the media)
• Blood is checked for sterility, homogeneity, viscosity and color

Answer 12

A. Raw Material Parameter

Question 13

A. Raw Material Parameter

___________ is the most important raw material used for agar preparation.

Answer 13

Water

Question 14

A. Raw Material Parameter

Parameters of water to be checked: (3)

Answer 14

presence of copper ions, conductivity and pH

Question 15

• Autoclaving is done to sterilized the media
• Indicators should be used to check temperature and pressure.
• Sterilization indicators: Biological indicators and Bowie Dick test

Answer 15

B. Sterilization Parameter

Question 16

B. Sterilization Parameter

• Suggested cycle temperature: Stage 1

Answer 16

(20-121°C)

Question 17

B. Sterilization Parameter

• Suggested cycle temperature: Stage 2

Answer 17

(<100-121°C)

Question 18

B. Sterilization Parameter

• Suggested cycle temperature: Stage 3

Answer 18

(121-121°C)

Question 19

B. Sterilization Parameter

• Suggested cycle temperature: Stage 4

Answer 19

(121-80°C)

Question 20

• Gross physical appearance to be checked: excessive bubbles/pits, unequal filling of plates, cracked medium in plate and freezing or crystallization
• Mean thickness of the medium in plate: 4.0+/- 0.2mm
• pH value must be checked before and after autoclaving

Answer 20

C. Physical Parameters

Question 21

▪ Control Organism
Inoculated in soybean casein digest (SCD) broth and incubated for __ hours to get a cell density comparable to ___ McFarland’s standards

Answer 21

D. Microbiological Parameters, 4, 0.5

Question 22

D. Microbiological Parameters:

Colony count should be ____ - ____ cfu/mL (0.08-0.1 absorbance at 625 nm) 10uL inoculum for selective/nonselective media

Answer 22

107-108

Question 23

In Microbiological Parameters:

Routine QC of microbiological performance of culture media

Answer 23

Ecometric Method
Productivity Ratio

Question 24

This is a very crucial parameter for the determination of the quality of media

Answer 24

E. Contamination Parameter

Question 25

E. Contamination Parameter

To check for contamination, it is suggested that:
Whole batch must be kept at least ___ days at RT then checked for any growth

Answer 25

3

Question 26

E. Contamination Parameter

Two plates from test batch must be incubated at ____ for __________

Answer 26

37C , 24 hours

Question 27

E. Contamination Parameter

If there is any growth, the process is repeated, and if again there is any growth, the prepared batch is inferred as _________________

Answer 27

contaminated

Question 28

is an indication of the level of solidification of the agar in the medium

Answer 28

F. Gel Strength Parameter

Question 29

F. Gel Strength Parameter
A gel strength of about ___ – ___ dynes/cm2 will give satisfactory results

Answer 29

300 - 500