Cronobacter sakazakii is a serious food pathogen. If you are looking for this pathogen, you want to detect this bacteria down to the last cell.
A part of the analysis is a streak on CCI agar. Therefore, the quality of the CCI medium is crucial to the analysis.
Cronobacter sakazakii should show blue to blue-green colonies on the CCI medium. This can be tested with CRM-CS.
Research shows that there is a difference in electivity between suppliers. The color of the colony can vary from blue to blue-green to green-yellow colonies. At one supplier, the medium contains undissolved substances that could be mistaken for colonies. The green-yellow colonies can easily be mistaken for unsuspicious Cronobacter sakazakii.
If this is the case at your laboratory, it is worth trying another media supplier for better electivity. To isolate the Cronobacter sakazakii properly, and Cronobacter not be missed.
Below are the CCI plates from four suppliers with the spread plate technique.
The used strain is Cronobacter sakazakii from reference material CRM-CS.