Dairy-based salad dressings are susceptible to Zygosaccharomyces parabailii (Zygo) growth, which causes spoilage by producing off-flavors. Zygo growth also damages packaging containers due to gas production during fermentation. Zygo, a yeast similar to Saccharomyces cerevisiae, is tolerant of low pH and can survive in high-acid dairy-based salad dressings, shortening the dressing’s shelf life. Therefore, the goal of this research was to evaluate the effectiveness of different organic acids to slow or stop Zygo growth over a 45-d period. Lactic, acetic, and gluconic acids were used alone and in different combination in a reduced-fat ranch dressing formulation. Ten different formulations of dressing were acidified to a pH of 4.1. A pre-enriched culture of Zygo was added to each sample until a final concentration of 10⁴ cfu/mL of Zygo was achieved. The dressing was stored in incubators at 4°C, 10°C, and 25°C for 45 d and evaluated at d 0 and every 5 d during the storage period for microbial growth using tryptone glucose yeast extract agar (TGYE) with 0.5% acetic acid for selectivity. The different acid combinations had varying effects based on storage temperature. At 4°C, no Zygo growth was observed; Zygo concentration was dependent on the acid’s ability to reduce the initial inoculated load. Gluconic acid had the most significant effect on initial Zygo death in all samples at 4°C, so samples prepared with gluconic acid had the least amount of growth over the incubation period. At 10°C, samples containing combinations of acids and gluconic acid by itself were less effective at preventing growth. Acetic acid and lactic acid by themselves were the most effective at reducing growth, but did not prevent it. Samples stored at 10°C generally had 1–2 log growth. At 25°C, the type of acids use played a less significant role as the cfu/mL reached 10⁷ after 10 d. These results highlight the importance of storage temperature compared with acid type or combination on Zygo growth. This information may be used by food manufacturers to extend the shelf life of dairy-based products that are susceptible to Zygo contamination.