The ChromID Sakazaki Agar from Biomerieux is a chromogenic medium for the selective isolation and identification of Cronobacter spp (Enterobacter Sakazakii) in powdered infant formula (PIF).
The medium also detects Cronobacter spp in ingredients, baby food and production environment samples.
ChromID Sakazaki Agar is a ready-to-use and optimised formulation based on the RandF Enterobacter sakazakii chromogenic plating medium formula (ESPM) described by L Restaino et al in RandF Laboratories.
It contains two chromogenic substrates that reveal the two enzyme activities of Cronobacter spp strains: D-glucopyranosidase, common to all Cronobacter spp strains; and BD-cellobiosidase, which enables the detection of weak D-glucopyranosidase strains.
As a result, this medium provides a high level of sensitivity.
Typical colonies are blue-grey to blue-black within 24 hrs of incubation.
It can be used in the standard ISO/TS 22964 method but has been specially adapted to the new short protocol.
This simplified protocol allows a single selective 24-hour enrichment for PIF, ingredients, baby food and production environment samples followed by an isolation on the ChromID Sakazakii medium.
Thanks to the Cronobacter Enrichment Broth (CEB) supplement added to high-quality Biomerieux Buffered Peptone Water, this short protocol provides a higher sensitivity and a greater recovery than the ISO/TS 22964 protocol.
This commercially available method allows 48-hour Cronobacter spp detection versus 72 hours for ISO and is also useful for highly contaminated samples such as PIF production environment samples.
