Among other constituents, the culture medium blood agar contains sheep’s blood (or another mammal’s blood) in solid gelatinous agar. Heating blood agar results in red blood cell breakdown and the consequent release of factors essential for the growth of particular bacteria such as Hemophilus influenzae and Hemophilus ducreyi.
After aforementioned heat treatment, blood agar takes on a brown color reminiscent of chocolate – chocolate agar.
Anand C et al: Pig and Goat Blood as Substitutes for Sheep Blood in Blood-Supplemented Agar Media. J Clin Microbiol, 2000 38(2):591-594. Go to reference
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