there are a lot of factors to take into consideration with your question, firstly surely if you are using sanitizer after cleaning then there should not be a problem from bacteria spread, are you getting poor swab results.
if you do decide not to use pressure washers then you will need hot water and a very large flow rate which will add dramatically to the factories water cost and some areas will take longer to clean.
Have you tried using your pressure washers with both a high pressure nozzle and a rinse nozzle attached with a tap to switch between the two this way you can adjust both the pressure and flow to suit what you are cleaning and only use the high pressure where needed
Chris suggestion of a thermatech machine would work but be a little slow and you would also have to ensure fumes from burner where vented out from the factory and depending on how far this was it could be a problem.
If you are getting high bacteria counts are all belts etc being removed dipped and inaccessible areas being cleaned on a regular basis also do high level areas like girders etc have a cleaning schedule as bacteria could be spreading from these areas.