L-Ornithine Decarboxylation Medium is used for the biochemical confirmation of Cronobacter spp. in food, in animal feed and in environmental samples. ISO 22964 describes a horizontal method for the detection of Cronobacter spp. and recommend this medium for biochemical confirmation of Cronobacter spp. Cronobacter (formerly Enterobacter sakazakii) is currently considered an emerging pathogen responsible for, un-weaned babies, risking severe meningitis and necrotic enterocolitis that can be the cause of mortality rate between 40-80%. The pathogenicity of Cronobacter for un-weaned babies makes it necessary to review the manufacturing process of the milk-based products specialized for babies, guaranteeing the absence of the bacteria in the final product Additional prevention measures at a hospital include the sanitary hygiene of the prepared food; reducing the time between the preparation and its administration, to impede the multiplication of microorganisms. Yeast extract provides nitrogen, minerals, amino acids and vitamins essential for growth, particularly of the B-group. Glucose is the fermentable carbohydrate providing carbon and energy. L-ornithine is added to test the presence of the enzyme ornithine decarboxylase. If the organisms possess such enzyme, it will be activated in an acid environment created by the initial fermentation of glucose. Once the amino acid is decarboxylated, diamine putrescine is produced. The result is an alkalinization of the medium, which turns it a purple or violet. Organisms without the enzyme will remain acidic due to the fermentation, resulting in a yellow color in the medium. Bromocresol purple is a pH indicator to indicate decarboxylase activity.
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