Bacteria is bacteria. Food bacteria is no different, with the slight caveat that if using it commercially, you should either use a known pure strain and rotate, or test culture randomly for pathogens.
Being that involved is definitely a labor of love. Even in a basic home lab you'd need incubator, deep freezer, autoclave, centrifuge, microscope, misc glassware, and then all the consumables.
If doing it on a small scale, you could get away with using substitutes... pressure cooker instead of autoclave. Dehydrator with temp setting for incubator. Surplus centrifuge. Glycerin from the pharmacy as cryoprotectant. And you could make consumables yourself. Make a meat broth for tryptone, can buy yeast extract from the store, etc. Or just use skim milk base for everything and ammonium hydroxide or sodium hydroxide to neutralize lactic acid buildup if you want to up colony counts. For aseptic handling, you could use regular syringes and a canning jar with a hole drilled in it and stoppered with a cheap rubber stopper, then inoculate. Lots of creative solutions.
But yeah, to do it all the time esp in dairy, you'd need to work for a culture house or in-house lab for a plant. And then it would quickly become the same thing, industrialized. Make a 1,000 liter batch, centrifuge, test for pathogens, repeat.
