CRYSTAL VIOLET TETRAZOLIUM AGAR BASE

Description

Microorganisms which are able to grow at refrigeration temperatures are usually referred to as psychrophilic. Species of Achromobacter, Alcaligens, Flavobacterium and Pseudomonas are included among the psychrotrophic bacteria as these organisms are able to grow relatively rapidly at commercial refrigeration temperatures. Many psychrotrophic microorganisms when present in large numbers can cause a variety of off-flavors as well as physical defects in foods. Their growth rate is highly dependent on temperature, and therefore, if the temperature is reduced, their growth rate is also slowed down. Thus the spoilage of refrigerated food is very much dependent on temperature. Crystal Violet Tetrazolium Agar Base is used for the detection of gram-negative psychrophilic bacteria causing food spoilage. It is based on the formulation by Olson and recommended by APHA for detecting gram-negative psychrotrophic bacteria. Standard methods for the detection of gram-negative psychrotrophic bacteria should be followed.