| abstract |
A microorganism culture medium comprising a derivative A′ of a chromogen A, and a chromogen B, where the chromogen A is a chromogen being oxidized to a colorant, and the chromogen B is a chromogen being reduced to a colorant. The derivative A′ acts as a substrate of an enzyme generated when a microorganism is growing, and is then converted to the chromogen A, and the derivative A′ and the chromogen B are substantially not colored in the culture medium unless a microorganism is inoculated. |