The way the butcher explained to me, it’s not so much the volume that’s the problem, it’s the time between cleanings which gives microbes time to multiply in ideal conditions with lots of nutrients from blood and optimal temperature. Any crevice that’s hard to clean becomes a focal point for contamination and it doesn’t really matter if you’re butchering one cow or a hundred, because if you leave that biofilm there for even a few days, it can grow enough to contaminate future batches.

The other side of it is that many forms of contamination sporulate, so short of using a powerful surfactant to wipe it all away, the spores will survive basically forever until they hit growing conditions.