Ayers & Johnson Agar (Stock Culture Agar) 500G

It is observed that in addition to supporting luxuriant growth, the medium also helped in maintaining the viability of Streptococci and various other organisms over a long period of time. They also observed that Streptococci maintained their viability for as long as four months when incubated in this medium at room temperature (25°C).The medium serves its main purpose (i.e. maintaining viability) chiefly due to its semisolid nature, a well-buffered environment and the presence of casein and dextrose, the latter, which serves as a source of energy. Many fastidious organisms like Mycobacterium species, S. pneumoniae , show good growth on this medium.