Comparison of an Improved Rose Bengal‐Chlortetracycline Agar with Other Media for the Selective Isolation and Enumeration of Moulds and Yeasts in Foods

摘要

Summary.A modification of the medium (RBC) of OvercastWeakley (1969) containing 50 p/m of rose bengal and 10 p/m of chlortetracycline was compared with the oxytetracycline‐glucose‐yeast extract medium (OGY) of Mossel, VisserMengerink (1962) and with acidified (pH 4·5) malt extract agar for the selective isolation and enumeration of moulds and yeasts in foods. The results obtained from several foods confirm earlier observations that media containing antibacterial agents are superior to acidified ones for isolating moulds from foods. Little difference in counts was observed for yeasts on the 3 media and there was no significant difference in the counts of moulds or the incidence of recovery of moulds on the RBC or OGY. Both media suppressed growth of bacteria but the RBC medium restricted the diameter of mould colonies thereby aiding counting and preventing overgrowth of slowly growing strains by more luxuriant species such as occurs on