I agree with others that Tissue Culture is much more stringent than bacterial culture.
Coming from more of a plant tissue culture background, microbiologists blow my mind. I would never consider working outside of a flow bench being sufficiently sterile, but microbiologists do it all the time. We sterilize every piece of equipment and do all of our work in the flow bench, if we didn't it would be a mess.
I have always doubted that bench work is good enough unless you are using highly selective media. The worst part about bacterial cultures is that you really dont know for sure if it is contaminated with another bacteria, especially if the other bacteria is similar. Personally I dont get why more precautions are not taken.
Just for the record, when I worked in a microbiology lab we used a flow bench and flamed everything.
Not really true.
Each microbe smells subtly different. I rotated in a yeast lab in grad school. Not only could the members of the group tell the difference between different wild type strains by smell, they could also make a reasonable guess at some of the mutant strains.
If you're ever not sure about your bacterial culture, you can sequence the 16s gene. It's not difficult or time consuming.
Plus, when you innoculate a flask of bacteria, you're adding a billion cells! That one Staphylococcus epidermis
that flops in doesn't stand a chance of overtaking your culture.
Not all microbes smell that strong, and if you have them growing together I doubt your nose would know. Sequencing the 16s gene may be a good approach, I dont really know, but the better approach is good sterile technique to avoid the problem in the first place. That one contaminating microbe may seem insignificant among the millions you add, but that dosnt mean that they cant co-exist, and you would no longer have a pure culture. Further, you are assuming that the million cells you add are pure to start with...
Contamination is not always obvious, and even if you think you have a pure culture you may not. Even with plant tissue culture, contamination is not always easy to see and can spring up months after you think it is clean. Why microbiologists gamble like this when the solution is relatively simple I will never know.