For improved haemolytic reactions of organisms. Dissolve 40gms in 1000ml of distilled water. Gently heat to boiling with gentle swirling and dissolve the medium completely. Sterilize by autoclaving at 15psi (121°C) cools to 45-50°C, add 5-8 % defibrinated blood (sheep, goat), mix well. Before adding blood, the prepared medium is clear and yellowish-brown, then blood coloured and not haemolytic.
SHEEP BLOOD AGAR BASE is used for improved haemolytic reactions of organisms. Medium represents rich nutrients which provide optimal growth conditions for all relevant microorganisms are used improved haemolytic reactions of organisms. Fresh, defibrinated sheep blood is most suitable for determining haemolysis forms. Preparation of boiled blood agar after adding the blood, heat the culture medium for about 10 minutes at approx. 80°C with frequent swirling until it turns brownish (chocolate colour). The pH value of 6.8 stabilizes the red blood corpuscles and favours the formation of clear haemolysis zones. If the culture medium base is to be used without blood, the pH should, however, be adjusted to 7.2 to 7.4 since most bacterial colonies appear somewhere earlier and grow better in a slightly alkaline medium. On addition of 1 % glycerol and 25 % human blood when isolating tubercle bacilli from sputum, since recognizable mycobacteria colonies grow from even minimal amounts of sample material. However, that 0.1 % glycerol and 2.5 % human blood together with 100 IU/mol of penicillin as a selective agent are sufficient. On addition of 5mg/l gentamicin (e.g. 0.1ml gentamicin solution) to blood agar permits selective cultivation of Streptococcus pneumoniae and other Streptococci sp. as well as bacterioides, Clostridium sp. and yeasts. For the selective cultivation of Aeromonas sp. recommends an ampicillin sheep blood agar. ** Atmosphere of incubation is enriched with 5-10% CO2.