Bacte LAB Agar prep, QC Flashcards
- 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
Culture Media
microorganisms with special nutritional/environmental requirement
Fastidious
microorganism that require only basic nutritional/environmental requirements
Nonfastidious
Classification of Culture Media
Based on Consistency:
- Liquid media
- Semi-solid media
- Solid media
- Biphasic media
Classification of Culture Media
Based on Use:
- Simple Media (general purpose/Supportive)
2.Enriched Media
- Enrichment Media
- Selective Media
- Differential Media
Simple Media (general purpose/Supportive) example
Nutrient Agar
Enriched Media example
Blood Agar Plate
Enrichment Media example
Thioglycolate broth
Selective Media example
MacConkey Agar
Differential Media
Hektoen Enteric Agar
Tubes for Biochemical Test
Butt - SIM
Slant - Citrate
Butt-slant - LIA and TSI
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
A. Raw Material Parameter
A. Raw Material Parameter
___________ is the most important raw material used for agar preparation.
Water
A. Raw Material Parameter
Parameters of water to be checked: (3)
presence of copper ions, conductivity and pH
- Autoclaving is done to sterilized the media
- Indicators should be used to check temperature and pressure.
- Sterilization indicators: Biological indicators and Bowie Dick test
B. Sterilization Parameter
B. Sterilization Parameter
- Suggested cycle temperature: Stage 1
(20-121°C)
B. Sterilization Parameter
- Suggested cycle temperature: Stage 2
(<100-121°C)
B. Sterilization Parameter
- Suggested cycle temperature: Stage 3
(121-121°C)
B. Sterilization Parameter
- Suggested cycle temperature: Stage 4
(121-80°C)
- 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
C. Physical Parameters
▪ Control Organism
Inoculated in soybean casein digest (SCD) broth and incubated for __ hours to get a cell density comparable to ___ McFarland’s standards
D. Microbiological Parameters, 4, 0.5
D. Microbiological Parameters:
Colony count should be ____ - ____ cfu/mL (0.08-0.1 absorbance at 625 nm) 10uL inoculum for selective/nonselective media
107-108
In Microbiological Parameters:
Routine QC of microbiological performance of culture media
Ecometric Method
Productivity Ratio
This is a very crucial parameter for the determination of the quality of media
E. Contamination Parameter
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
3
E. Contamination Parameter
Two plates from test batch must be incubated at ____ for __________
37C , 24 hours
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 _________________
contaminated
is an indication of the level of solidification of the agar in the medium
F. Gel Strength Parameter
F. Gel Strength Parameter
A gel strength of about ___ – ___ dynes/cm2 will give satisfactory results
300 - 500
