A comparison study between Oxyrase anaerobic agar plates and conventional anaerobic method for the enumeration of lactic acid and bifidobacteria fromfermented milk

The traditional cultural methods to detect and enumerate anaerobic or facul tative anaerobic microorganisms need special techniques to prevent antibact erial effects of oxygen during the procedure. Supplementation of media with oxygen reducing membrane fragments (Oxyrase) for detection of anaerobic or facultative anaerobic bacteria was tested for the enumeration of lactic ac id bacteria in fermented milk products. In comparison with aerobic and CO2- incubation conditions the colony counts on the appropriate media were incre ased for streptococci only negligible for the lactobacilli slightly. The co lony dimension (diameter) of course, which can be seen as a more sensitive indication of better growth conditions, was increased significant with all lactic acid bacteria in comparison with aerobic incubation and in the tende ncy in comparison with CO2 incubation.