Orange Serum Agar

Orange Serum Agar is used for the cultivation of aciduric microorganisms associated with spoilage of products and is not intended for use in the diagnosis of disease or other conditions in humans. The low pH of fruit juices makes citrus fruit products susceptible to spoilage by yeasts, molds, and the bacteria Lactobacillus and Leuconostoc. In the 1950’s, Hays investigated spoilage in frozen concentrated orange juice. He found that an agar medium containing orange serum (juice) was superior to Lindegren Agar in isolating the microorganisms responsible for spoilage causing a buttermilk off-odor. Murdock, Folinazzo, and Troy found Orange Serum Agar, pH 5.4 to be a suitable medium for growing Leuconostoc, Lactobacillus, and yeasts. Orange Serum Agar is recommended for examining fruit beverages.