I take umbrage at the misconception brought up constantly that Reb Moshe was a da'as yochid on milk from companies in the US.
1. Reb Moshe was not mechadesh the heter. It was an accepted psak before he arrived. Rabbonim were meikel, albeit never wrote Teshuvos.
When R' Moshe came to the US in 1937, pure milk regulations were at most 30ish years old, but mostly (at the federal level) fairly new from within the last decade - New Deal era laws.
To call whatever psak there was from whatever rabbanim were there "accepted psak", when the metzius of commercial/industrial milk production and its regulation was itself so new...
There's no "mesorah from past generations" for anyone to know about.
There's also no mekor for "doros of erlicher yidden" in the US... How many medakdikim in halacha were there in the US pre 1900? a couple of hundred? total since Jamestown?
My family has been in the US for over 110 years shomer shabbos - One great grandfather was a Rav who did not leave his house on shabbos so he wouldn't see the chillul shabbos. The other GGF was a shochet - (which wasn't a raaya that he kept shabbos as anyone who knows the metzius could tell you) and then a mocher seforim after he was in a sleigh accident traveling the thousand islands region to shect for people. Go get some books about what the Metzius was...All for the Boss, Lieutenant Birenbaum, Tzidkus stands Forever...
This is just historical ameratzus, plain and simple.
This goes for the sugyas you throw out there too
It is pretty clear that Yidden cross the Williamsburg bridge on Shabbos (opened dec 1903), cover their hair with a sheitel that looks like their own (truly look like their own is a recent invention), shave with a machine (invented in 1915), and say Mezonos on a pretzel (Hard - invented 1850, Soft - last 1800's intro to US).
Regarding
Rabbonim were meikel, albeit never wrote Teshuvos.
sorry to go modern on you but "pics or it didn't happen". There are hundreds if not thousands of teshuvos written by american rabbanim in the early decades of the 20th century, on many many different topics - and it's reasonable to expect that if there was a "accepted psak" that honestly is quite a chiddush - we would have a written record of it. (my GGF has a long back and forth in his tsuva seforim with Rav Henkin about a chiddush of his regarding the kashrus of stam grape juice - but nothing regarding stam milk...
)(Hebrewbooks was started to preserve these tshuvos...)
(It's like the assertion that the minhag was always a 72 minute alos. R' Dovid Braunfeld searched hundreds of luachs and seforim written pre-war and older, and didn't find even ONE backing the claim, but the proponents say "it's was the minhag, just not written...
)
The Shulchan Aruch does not mention government supervision.
Correct. It does mention what milk requires in order to be considered "Cholov Yisroel": supervision by a jew.
Anything else is Chalav Akkum.
Putting a name tag on a goy that says "FDA", does not make him a yid.
@Dan I sort of enjoy watching these kind of people making themselves look silly. I think you were a bit quick on the ban button...sorry, rule 11...