We investigated the growth parameters of Saccharomyces rouxii isolated from spoiled chocolate syrup. The optimum pH range for S. rouxii was 3.5 to 5.5, whereas the minimum and maximum pH values that permitted growth were 1.5 and 10.5, respectively. For cells grown in 0 and 60% sucrose the optimum water activity (a,) values were 0.97 and 0.96, respectively. The optimum temperature for S. rouxii increased with a decreasing a, regardless of whether glucose or sucrose was used as the humectant. The optimum temperatures for S. rouxii were 28°C at an a. of >0.995 and 35°C at an a, of 0.96 to 0.90 in 2x potato dextrose broth with sucrose. Increasing the sorbate concentration (from 0.03 to 0.10%) caused the growth of S. rouxii to become more inhibited between a,s of >0.995 and 0.82. S. rouxii did not grow when the sorbate level was 0.12% (wt/vol). At lower sorbate levels, the effect of sorbate on the growth of S. rouxii depended on