The point that myself and others here are trying to make is that these types of toxins are VERY rarely if ever seen in home brewing. Mostly because of a combination of factors including the boiling of wort, the low ph, the preservative nature of hops, the presence of alcohol, etc. Not saying it couldn't happen, but the possibility for this type of infection is rare.
To get back to the original topic that fueled this, it's a stretch to make an argument in home brewing for using sanitary fittings to prevent this type of infection. Yes they're nice and don't have all the nooks & crannies for stuff to hide, but when you look at the rest of a brew rig that includes barbed hose fittings, threaded pump fittings, pump head internals, plate chillers, false bottoms, etc. there are just too many other areas that could allow potential nasties to breed. The bottom line is that either welded sanitary fittings or o-ring based weldless fittings are just fine for home brewing and using one over the other is not going to get you out of the risk of an infection.
I'm not arguing that TCs probably aren't overkill for the home brewer. I'm just raising the point that just because there aren't / haven't been significant issues doesn't mean that there couldn't be issues. My original issue was with your statement "no issue" associated with weldless fittings. That statement remains de facto wrong. The risk is low but probably acceptable for a home brewer. On the other hand, if I brought a tank with a weldless fitting on a product contact surface into a process at my plant, I'd get b-tch-slapped by my quality manager. Different world. At work, we have to have processes that have food safety designed in for a couple of reasons. First, I can't guarantee that every person who works on the process knows all of the gory details about how to effectively clean harborage points, etc. Second, we couldn't afford to tear down every single non-sanitary fitting and manually clean it. Designing to 3A standards is a pre-req for being able to truly do CIP. Otherwise, we couldn't have one guy clean 5 1000-gallon vessels, about 600' of process piping, a few dozen valves, and a couple of plate heat exchangers all in about 3 hours, 4 max.
Here's another example of how anal we are at work - most of our equipment framing is square 304 stainless tube (product surfaces have to be 316, but 304's ok for framing). If you want a hook or something, it has to be welded on. No drilling a hole and putting a bolt in. Why? During cleaning, water could get in with some contaminants and the interior of the framework could harbor something. Again, it's a different world. You could do surgery in our cold filling rooms (and the scrub-in procedure is only slightly less rigorous).
If I weren't DIYing TCs onto my kettles, Stout would probably be my first choice, since at a glance, their product line looks the most like everything I work with at my day job.
And just to nitpick - our pHs aren't low. That's why people who make and store starter wort have to go through canning conditions. pH 5 isn't low. A good rule of thumb for a liquid product - if it's not in the refrigerated section and it wasn't sterilized in-process, it's got enough acidity. Fruit juices (pH 2-4), soda (pH 2-3), etc. Even those can spoil after opening.
Please describe your sanitary beer homebrewing setup. What is your cleaning procedure?
Currently under construction, but uses TC fittings everywhere feasible, and most product contact surfaces are stainless. The only fittings that don't satisfy sanitary design criteria would be the hose barbs, weldless fitting on the cooler MLT (which will probably get upgraded to a SS MLT eventually), pump internals, and the NPT fittings on the inlet/outlet of my plate cooler (plates themselves are usually CIPable with sufficient flow). The ball valves aren't CIP-able, but do have TC-fittings. Tank fittings are all TCs, the HERMS coil is stainless with TCs, etc. I even got lucky and scavenged a couple of sanitary RTDs with tri-clamp fittings from a pile of equipment heading off to be junked at work.
Cleaning procedure post brew will be along these lines:
MLT: Remove and dispose of mash solids. Rinse with water until no visible product residue remains. Remove false bottom, tear down fittings, and clean by hand (scrub with cleaner, rinse, star-san, dry. For the MLT itself, hook up to a higher-flow pump, circulate hot PBW solution through MLT (with a sprayball), one of the pumps, HERMS coil. If I'm not getting enough flow through the rest of the tubing, I'll circulate the HERMS coil separately. I'll probably start with ~20 minutes at the concentration on a PBW package and ~140-150F. Then rinse to clean water, a quick star-san circulation, then remove weldless bulkhead and hand-clean around the bulkhead and all threaded product contact surfaces.
BK: Remove and manually clean trub filter / pickup tube separately. Rinse away all visible solids from BK to drain. Reconnect discharge tubing, fill BK with hot water from tap, and flush through tubing and plate until no visible residue. Reverse flow through plate to backflush. Then, circulate with hot PBW solution, sprayball in the tank. Use a booster pump as needed to get needed flow through plate. Rinse and drain, circulate star-san, and drain. If I'm not satisfied that the plate is getting cleaned, I'll bake it.
Tubing/barbs - pull off barbs, toss in bucket with warm PBW solution. Nylon bristle bottle-brush (of appropriate diameter) to get inside first few inches of tubing. Hose barbs scrubbed by hand. Star-san and dry.
Pumps and valves - I'll probably do a tear-down after my first batch to see how the internals of the head fared and decide from there. If the water flushes are sufficient to get to no visible residue on contact surfaces, I might just let them pass with the CIP only. You figure that there will be no shortage of localized turbulence inside the housing, which helps. I did get the 3 piece ball valves so that teardown will be easier for those.
Next brew-day, re-assemble everything dry, do a quick circulation of star-san through then HERMS, MLT, BK, plate, and pumps while the strike water is warming up.
The key takeaway here is that you can use other fittings as long as you understand where they can be problematic.
