2. Blood Agar. Most commonly used medium
Blood Agar. Most commonly used medium. 5-10% sheep or horse blood is added to melted agar at 45-50°C. Blood acts as an enrichment material and also as an indicator. Certain bacteria when grown in blood agar produce haemolysis around their colonies. Certain bacteria produce no haemolysis.
Types of heamolysis :
(a) beta, the colony is surrounded by a clear zone of complete haemolysis.
(b) Alpha (a) haemolysis. The colony is surrounded by a zone of greenish zone due to formation of biliverdin.
(c) Gamma (y) No haemolysis, there is no change in the medium surrounding the colony,

3. Blood agar : 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. β- Hemolytic activity will show lysis and complete digestion of red blood cell contents surrounding a colony. Examples include Streptococcus haemolyticus. α-Hemolysis will only cause partial lysis of the red blood cells (the cell membrane is left intact) and will appear green or brown, due to the conversion of hemoglobin to methemoglobin. An example of this would be Streptococcus viridans. γ-Hemolysis (or nonhemolytic) is the term referring to a lack of hemolytic activity.[6] BAPs also contain meat extract, tryptone, sodium chloride, and agar.

5. Chocolate agar (CHOC) or chocolate blood agar (CBA) – is a non selective, enriched growth medium used for isolation of pathogenic bacteria. It is a variant of the blood agar plate, containing red blood cells that have been lysed by slowly heating to 80 °C. Chocolate agar is used for growing fastidious respiratory bacteria, such as Haemophilus influenzae and Neisseria meningitidis. In addition, some of these bacteria, most notably H. influenzae, need growth factors such as NAD (nicotinamide adenine dinucleotide)= (factor V) and hemin= actor X), which are inside red blood cells; thus, a prerequisite to growth for these bacteria is lysis of the red blood cells. The agar is named for the color and contains no actual chocolate
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