Dear experts,
I observed the phenomenon that when we leave the blood agar plate for over 3 months, there was a change from red to extreme dark red ( or light black color). I would like to ask what happened in the blood agar plates. Are there any changes in the pH? Similar phenomenon happens when I put the blank blood agar plate overnight in the 5%CO2 incubator at 37oC, the red color changed to dark red color (without bacteria). Could anyone suggest the reason for this?
Any suggestions, and explanations on any aspects such as hemoglobin oxidation, acidification, pH changes, etc are appreciated,
Thank you very much for your time and help in advance,
Regards,
Le Phuong.