The antimicrobial effectiveness of sodium benzoate and potassium sorbate (0.05, 0.10, 0.20 and 0.30%, wt/wt), separately and in equal combinations, were evaluated against the growth of Zygosaccharomyces bailii in an artificially inoculated salsa mayonnaise stored at room temperature (23 to 25°C). Potassium sorbate was able to suppress the growth of Z. bailii significantly (P < 0.05) more than sodium benzoate did, whereas no significant difference in growth was calculated between potassium sorbate and the combination in equal amounts of the two preservatives. Equal concentrations of the two preservatives were, however, significantly (P < 0.05) more effective than sodium benzoate in suppressing the growth of the yeast in a salsa mayonnaise. At the investigated concentrations, the preservative systems did not prevent spoilage of the product by Z. bailii . Therefore, the use of yeast-free ingredients, clean and sanitary equipment, and strict adherence to good manufacturing practices during manufacture and packaging is required to produce a salsa mayonnaise free of spoilage microorganisms.
Keywords: mayonnaise; preservative.