Why is the agar in the Petri dish red?
The red blood cells remain intact in the agar and make the plates a blood red color. It is an enriched, non-selective differential medium that supports growth of a variety of bacteria and can detect hemolytic activity of the microorganism.
What type of bacteria grow on blood agar?
Blood Agar is used to grow a wide range of pathogens particularly those that are more difficult to grow such as Haemophilus influenzae, Streptococcus pneumoniae and Neisseria species. It is also required to detect and differentiate haemolytic bacteria, especially Streptococcus species.
Which agar is red?
MacConkey Agar
Result Interpretation on MacConkey Agar The red colour is due to production of acid from lactose, absorption of neutral red and a subsequent colour change of the dye when the pH of medium falls below 6.8.
Why are blood agar plates used?
Blood agar is a general purpose, enriched medium often used to grow fastidious organisms and to differentiate bacteria based on their hemolytic properties.
How do you sterilize blood agar?
Boil to dissolve the agar, and sterilize by autoclaving. To sterile Blood Agar Base which has been melted and cooled to 45 to 50°C, add 5% (vol/vol) sterile defibrinated blood that has been warmed to room temperature.
What are petri dishes made of?
glass
A petri dish is a flat, shallow dish made of glass or plastic with a suitable lid. A petri dish is used to culture different types of cells, including bacteria and molds. It often contains a nutritional medium on which the cells can grow.
What are blood agar plates?
Blood agar plates (BAPs) contain mammalian blood (usually sheep or horse), typically at a concentration of 5–10%. BAPs are enriched, differential media used to isolate fastidious organisms and detect hemolytic activity.
Why is human blood not used in blood agar?
Agar prepared with human blood is not recommended, partly because of the safety risk to laboratory personnel, but mainly because it is said to result in poor bacterial isolation rates, although there are few published data to support this (2).
How long do blood agar plates last?
Stack them (plates) like 5-10. The middle ones won’t get moisture. They will be safe for 1-2 weeks or more at 2-8 ºC if the fridge is in good conditions.