It depends on your purpose. For example, if you want to study a protein function and need to get large amount of it. Then you may transfer a plasmid which can express this protein into a bacterial like E.coli. This is a great method in scientific researches. But this also needs to be strictly controlled in case of mutation or something else to create an uncontrolled creature.
you answered yourself there buster.
They are typically referred to as Lactic acid bacteria.
