Description
Orange Serum Agar AM 142 is based on the formulae described by Hays and Murdock in 1951 for the cultivation and total count of organisms and yeasts capable of surviving the low pH found in fruit juices and orange juice concentrates, and causing ‘off-odour’ spoilage.
Much work was performed and documented by people such as Hays, Murdock and Brokaw, Hays and Riester, Murdock, Folinazzo and Troy, to establish that the described formulae of Orange Serum Agar and a variant, Orange Serum Broth concentrate, produced high counts and both Hay and Murdock confirmed that they were superior to Tomato Juice Agar for the maximum growth of putre¬factive organisms found in juices.
Organisms that may be isolated by the fruit processing industry include aerobes, such as acetobacter and Bacillus coagulans; microaerophils, such as lactobacilli and leuconostoc; butyric acid-forming anaerobes, such as clostridia and saprophytic and pathogenic yeasts and moulds.
Of the above mentioned list, leuconostoc and some strains of lactobacillus tend to grow in high numbers at this pH and are associated with spoilage. Yeasts may also be implicated.
