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. 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. BAPs also contain meat extract, tryptone, sodium chloride, and agar.