Comparison of combinations of diluents and media for enumerating Zygosaccharomyces rouxii in intermediate water activity foods

Combinations of five diluents (0.1% peptone, 40 and 50% glucose, and 18 and 26% glycerol) and three enumeration media (tryptone glucose yeast extract, dichloran 18% glycerol and malt extract yeast extract 50% glucose (MY50G) agars) were evaluated for recovering a xerotolerant yeast, Zygosaccharomyces rouxii, from foods with intermediate water activity (a w ). Combinations of 40% (a w 0.936) or 50% (a w 0.898) glucose diluent and MY50G agar (a w 0.890) were superior in recovering highest populations. The type of solute in the diluent, as well as a reduced a w , influences efficiency of recovering viable cells