Question

Mannitol salt agar is defined as both a selective and a differential agar since it selects against non-halophiles and allows the researcher to distinguish between organisms that vary in their ability to ferment mannitol. True or false?

Answer 1

Answer: The above statement is true

Explanation:

Mannitol salt agar is a medium which contain high concentration of salt,about 7.5%-10%. It is commonly used as a selective and differential growth medium.Because of its high concentration of salt,it inhibits growth if non halophiles(as they only grow best in media containing less tha 0.2M salts). If the bacteria can ferment mannitol,an acidic byproduct is formed which turns phenol red agar into yellow.So only those bacteria grow well which can ferment mannitol.