Hi there,

The easiest is to start from an isolated clone and to check its phenotype according to the strain genotype (auxotrophy markers and antibiotics resistance/sensitivity).

Hello, first use solid media and see any difference in colony morphology after growth. If you have the ability to make a microscope just use it to see the stains which are nicely visible under phase contrast microscopy if any bacterial contamination you can easily detect it.

You could try to test the MUT property