Sailor,
I don't think we have changed brine in years, in fact I am certain of it. We use an ultra-filtration membrane, inline chlorine dosing and automated salinity. Listeria, like everywhere else in the plant, is on a sampling plan.
That't not much help to you but what we do for feta may be. We store feta for 4 weeks minimum in brine from the make. After the make the whey boiled with a steam pipe, salt added and is stored in barrels till after cheese draining. It is allowed to cool. It is then pumped into the aging containers and the cheese lowered in on racks. The whey/brine is dumped after each batch of feta is aged.
Others,
Whey not only provides acidity but also calcium. I would still add as much whey as you can to any brine, beer or not.