The enumeration of Streptococcus thermophilus (Str) in the presence of Lactobacillus acidophilus (LAC) and Bifidobacterium longum (BL) on ST agar at 37degreesC/48h/aerobically and on Lee's agar at 37degreesC/48h/microaerophilic condition were shown to be non-selective for Str. ST agar allowed the growth of LAC and Lee's agar supported the growth of LAC and BL. ST agar (aerobically) and Lee's agar (aerobically and under microaerophiliae) were incubated at 30, 35, 37 and 45degreesC. At 30 and 45degreesC LAC with ST agar and either LAC and BL with Lee's agar were inhibited. The recovery of Str was efficient under all conditions. The tests were carried out using isolated and mixed suspensions of these microorganisms. Counts were also made with Str fermented skim milk with added probiotics. The ability of each medium to inhibit the organisms was also tested.5941858370372