Incorrect preparation of the nutrient-deprived media.

Dr. Lee: ‘If the contamination doesn’t seem widespread, another issue could be incorrectly prepared media. Let’s review the preparation steps. Check your lab notebooks: Were all components measured and added properly? Did anyone notice any issues during the preparation process?’

Elena: ‘Dr Lee, our media were already prepared so this cannot be the issue.’

Dr. Lee: ‘Good observation Elena.’

Consider your other options: