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Effects of pH and Water Activity on Microbiological Stability of Salad Dressing
R S Meyer1, M A Grant1, L O Luedecke2
1Nalley's Fine Foods, Inc., 3303 South 35th Street, Tacoma, Washington 98411.
Abstract:
The water activity and pH of an experimental starch-based salad dressing were varied to evaluate inhibitory effects on microorganisms selected from groups known to be principal dressing spoilage agents. Dressing samples were inoculated with Lactobacillus fructivorans , Zygosaccharomyces bailii , or a yeast isolated from a spoiled commercial salad dressing. Both yeast and L. fructivorans displayed a minimum growth pH of approximately 3.55 to 3.60. The minimum aw observed was 0.89 for yeast growth and 0.91 for L. fructivorans . Combinations of aw and pH which imparted microbial stability without use of preservatives are described.
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