Enumeration of Staphylococcus aureus in foods with special reference to egg-yolk reaction and mannitol negative mutants.

摘要: A comparison between the original tellurite-glycine medium (Zebovitz. Evans and Niven, 1955) Chapman's (1945) sodium chloride-mannitol-phenol red agar has shown latter's superiority for enumeration of Staphylococcus aureus. Nevertheless had three shortcomings. First, besides micrococci, many Bacillus species grow well on this may therefore obscure colonies S. The Bacilli be virtually eliminated by adding 1 mMol/liter azide to medium. Next, it was confirmed that some strains ato'eus lose their capacity dissimilating mannitol; among 1160 strains, mostly from clinical sources, 4.4% were found unable dissimilate manoitol aerobically. To permit detection such mutants agar, addition 0.5% glucose effective, although numbers coagulasenegative, catalase-positive cocci, growing with a typical halo, further increased measure. last disadvantage viz. its inhibitory properties (due high NaCI content), towards sublethally impaired cells aureus could not overcome at all. Therefore, suitability most recently developed modified tellurite-glycine-eggyolk Baird-Parker (1962) evaluated. Out 522 human food origin 97.5% characteristically Baird-Parker's agar. coagulase-negative, Lancefield group D streptococci, Proteus Bacillas developing quite limited generally did lead overcrowding above has, so far, rendered excellent service in ecological studies occurrence development foods incriminated staphyloenterotoxicosis.