You said bacteria in a softener, now you're off into filtration.
From your link to the guys selling a Pur-Gard... "When contaminants accumulate in a softener, they can seriously impair its ability to function properly, degrade water quality, and even result in premature mechanical wear or failure."
Now for that to happen means the softener is not backwashing correctly. So are you now saying bacteria can build up in an improperly operated softener with incomplete backwashing? If so I'll agree but, that is not what you said originally.
I see that those guys are also selling an annual softener service, just as if it is actually needed.
My claim is that harmful (read Coliform etc.) bacteria does not build up or become more of a problem in a softener because the water in a softener is replaced (a number of times actually) with each regeneration.
You should note that even in a house with a Legionella bacteria problem in the water heater, there is no mention of the same bacteria in the softener in the same house on the same water. Why do you suppose that is?
Bacterial growth is not limited to the water heater tank alone. Studies have found that even with increased water tank temperatures the bacteria will continue to propagate in the piping system itself and parts thereof. Simply raising the temperature of the water to above 160 in the tank will kill those bacteria in the tank but not in the rest of the system which is why Watts (and the code though nobody follows it) say to install an ASSE1040 tempering device at the point of use. Though a softener in good working order does indeed backwash the system there is plenty of time for bacteria to propagate during the time when the tank is in normal use and there is no proof that the back wash cycle will remove and or kill any and all bacteria present. Some bacterial strains do quite well in a salty environment.
Had I taken the time to watch their video concerning ASSE 1040 tempering devices and the connection to increased water temperatures and the ineffectiveness of simply raising system temperatures in an attempt to alleviate bacterial growth "within the system" .... the Watts link you posted doesn't show anything about the video but..." now I guess Watts and you are saying pasteurization doesn't work. LOL I suppose you sell the Pur-Gard too.
Watts is not saying that pasteurization does not work. They are saying that it is ineffective when limited to the storage tank alone. And no, I do not sell Pur-Gard
Tell me, how would anyone know there was more bacteria in a softener than the feed water going into it?
Good question and I suppose by assumption unless some lab has run tests but without wading through a lot of pages I can't say for sure
Also, what type of harmful bacteria might we find in a bag of salt?
Again, don't know, I assume that the salt has been treated and cleaned before bagging so hopefully none but why is bacteria in salt an issue? I guess one could make an argument for bacteria settling in the brine tank should someone leave the cover off but I am going under the theory that the bacteria we are talking about is coming from the water source.
As to non harmful bacteria in a filter, I've seen that may times in disposable cartridge filters; clear to black slimy, smelly etc. build up, same as in toilet tanks but softeners aren't filters that trap bacteria and the food they use to survive. I knew it was non harmful because a Coliform bacteria test found none.