Isolate and enumerate spoilage organisms of citrus products with Thermo Scientificâ„¢ Oxoidâ„¢ Orange Serum Agar (Dehydrated). Orange Serum Agar is developed specifically for the isolation and enumeration of microorganisms that are capable of surviving citrus products.1 The low pH of these products limits the growth of microorganisms to those capable of tolerating the acidic environment. Organisms known to grow in single strength and concentrated citrus juices are lactic acid and acetic acid bacteria, yeasts, and molds2. Of this group of organisms, lactic acid bacteria have been mainly implicated as the cause of spoilage and these have been identified as Lactobacillus plantarum, Lactobacillus brevis, Leuconostoc mesenteroides and Leuconostoc dextranicum3.Tryptone in the medium provides amino acids and other complex nitrogenous substances while glucose serves as fermentable carbohydrate and energy source. Yeast extract supplies vitamins which stimulate growth. Orange serum provides an optimal environment for the recovery of acid tolerant microorganisms from citrus fruit products.In comparative studies carried out by Murdock et al.4 Orange Serum Agar was found to be a superior medium when compared to other media used for the total count and detection of spoilage organisms.Not all products are available for sale in all territories. Please inquire.Remelâ„¢ and Oxoidâ„¢ products are now part of the Thermo Scientific brand.