60k kids have avoided peanut allergies due to 2015 advice, study finds

I have a great example of this. For our first kid, we had created a Sterile Field in our kitchen for pacifiers, baby bottles, etc. The sanctity of the Sterile Field was never violated. We would wash things by hand and then BOIL them and place them into the Sterile Field. This kid is allergic to tree nuts and a few other things.

For baby number 2, soap and water is enough. There's no time for Sterile Field nonsense. This kid isn't allergic to anything.

There was a local mom who had 4 thriving kids. When their baby dropped the pacifier in the dirt, it just got brushed off and handed back to the baby. I don't think those kids had any allergies.

For what it’s worth I was raised like kid 2 and have a bunch of annoying allergies. It’s far too messy to look at individual cases.

Same. I grew up on a farm and was constantly outside and around dogs and horses. I need allergy shots as an adult.

I wonder if smearing a bit of probiotics on the pacifier could work even better than dropping it in the dirt?

The thing is, the sterile field is actually very important... for the first 3 or so months though. The immune system isn't developed enough yet and many medicines cause more harm at such a young age.

However this doesn't need to continue very long until basic cleanliness and medicine can be used effectively without harm.

I've not seen a lot of research about how allergies develop as you get older.

For me, as a kid: very, very allergic to cats, kinda allergic to many food items and a little to horse hair (only noticable when shedding in the spring)

As a young adult: Only 2-3 food allergies remain, cats still strong, hayfever starts.

Then I took some shots against the hayfever for 2-3 years, and the cat thing has mostly improved and the hayfever is basically gone. So only 2-3 food items remain.

without knowing anything, that sounds more dangerous for an infant to me

Probiotics is basically a marketing term, and scientifically meaningless. So: no.

As an adult I developed an allergic contact dermatitis reaction to some sulfates (sodium lauryl sulfate definitely, sodium laureth sulfate definitely, and something in raw onion juice) after a bad burn on one of my fingers. Probably due to exposure while it was healing, since it's in a lot of soaps like Dawn have one or more of the two. Self-testing to find a soap that didn't blister my hand and then to narrow down which ingredients caused the reaction was a long & unpleasant process. So it's definitely possible to develop new allergies as an adult, as well as to lose existing allergies.

Citation? I see studies testing the impact of various alleged-probiotic bacteria fairly frequently. What am I missing?

I wouldn't go as far as the commenter above but probiotic strains that we can actually produce are an absolutely tiny fraction of the bacteria that can exist in our gut. There's a reason fecal transplants are a thing, and it's not because they're fun for all involved.