The effect of pH, sodium chloride, sucrose, sorbate and benzoate on the growth of food spoilage yeasts

The effects of pH, concentration of NaCl, concentration ore sucrose and concentrations of sorbic and benzoic acids on growth were examined for 30 strains of food spoilage yeasts, representing Debaryomyces hansenii, Yarrowia lipolytica, Kloeckera apiculata, Zygosaccharomyces bailii, Zygosaccharomyces rouxii, Kluyveromyces marxianus, Pichia membranaefaciens, Pichia anomala and Saccharomyces cerevisiae. Zygosaccharomyces bailii did not grow at pH 7.0 and Z. rouxii, Kl. apiculata and P. membranaefaciens did not grow at pH 8.0. Only KI. apiculata grew at pH 1.5-2.0. The remaining species grew at pH 2.5-8.0. None of the species grew at 20% NaCl but strains of D. hansenii, Z. rouxii and P. anomala grew at 15% NaCl. S. cerevisiae and K. marxianus were the least salt tolerant, showing no growth at 7.5% NaCl and 10% NaCl, respectively. Medium pH influenced growth in the presence of NaCl. For Y. lipolytica, D. hansenii and S. cerevisiae, greatest tolerance of NaCl occurred at pH 5.0-7.0, but for KI. apiculata, D. membranaefaciens and Z. bailii best tolerance occurred at pH 3.0. K. apiculata grew in the presence of 12.5% NaCl at pH 2.0. All yeasts grew at 50% sucrose, with Z. rouxii, Z. bailii and P. anomala and D. hansenii growing at 60-70% sucrose. Medium pH in the range 2.0-7.0 had little effect on ability to grow in the presence of high sucrose concentrations. Z. bailii and Y. lipolytica were the species most tolerant of sorbate and benzoate preservatives (750-1200 mg l(-1)) at pH 5.0. (C) 1997 Academic Press Limited.