CRONOBACTER SELECTIVE BROTH BASE (CSB)
Principles and uses
Cronobacter Selective Broth (CSB) is a selective medium for the enrichment of Cronobacter spp. from food products and ingredients intended for human consumption and the feeding of animals, and environmental samples in the area of food production and food handling. The ISO normative 22964 recommends this medium for the selective enrichment of Cronobacter spp.
Enzymatic digest of animal tissues and meat extract provide nitrogen, vitamins, minerals and amino acids essential for growth. Sodium chloride supplies essential electrolytes for transport and osmotic balance. Sucrose is the fermentable carbohydrate providing carbon and energy. Bromocresol purple is a pH indicator. Cronobacter (formerly Enterobacter sakazakii) is currently considered and 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 and reducing the time between the preparation and its administration, to impede the multiplication of microorganisms.
ISO 22964 FDIS:2016 describes a horizontal method for the detection of Cronobacter spp. and recommend this medium for the enrichment of Cronobacter spp. in food, in animal feed and in environmental samples. A yellow/orange coloration in the broth after incubation (due to sucrose fermentation) indicates presumptive Cronobacter. If the broth is still purple in colour after incubation, the sample is presumed to be negative for Cronobacter.
