With reference to the Jewish prohibition of the eating of pork:
– The phrase as scarce as pork chops in a Jewish boarding house, and its variants, mean: extremely rare.—Cf. also the phrase as scarce as rocking-horse manure.
– The phrase like a pork chop in a synagogue, and its variants, mean: out of place; also unwelcome or unpopular.—Cf. also the phrase to stick out like a sore thumb.

 

AS SCARCE AS PORK CHOPS IN A JEWISH BOARDING HOUSE

 

These are, in chronological order, the earliest occurrences of the phrase as scarce as pork chops in a Jewish boarding house and variants that I have found:

1-: From The Price We Pay, by the U.S. cartoonist and columnist Jim Nasium (Edgar Forrest Wolfe – 1874-1958), published in The Pittsburgh Press (Pittsburgh, Pennsylvania) of Sunday 20^th October 1907:

Say! are you one of these guys who grab at this “How to be healthy” or “How to get rich” dope, or the “How to live to be a hundred years old” or “How to gain grace and beauty” articles in the magazines and daily papers? […]
[…]
You can take it from me, kid, that if every guy who goes up against this dope would weigh the cost as carefully as he does when he stacks up against the butcher or the iceman, the ones who wouldn’t pass it up would be as scarce as pork chops in a Jewish boarding house.

2-: From The Buffalo Enquirer (Buffalo, New York) of Monday 1^st December 1913:

WHEN CUTLER AND LEWIS MET.

Writes Howard Carr in the Chicago Inter-Ocean: “There has been many a tough battle fought between a set of ring ropes in the building that is now the Globe theater, where Charley Cutler and “Strangler” Ed Lewis wrestled Wednesday night. It is doubtful if a more vicious contest in a bout with the gloves was ever staged than the match that took place between the two burly grapplers. When the Globe was the old armory and Paddy Carroll was the matchmaker, a wrestler was as scarce as a pork chop at a Jewish feast. And if any one would have told a fight fan in those days that a pair of mat artists would raise a thousand wildly excited people to their feet he would immediately have been called a “bluejay” and the chances are he would have been sent to the detention hospital for observation as to his sanity.”

3-: From The Atlanta Constitution (Atlanta, Georgia) of Sunday 7^th March 1920:

Moley Is Certain Barons Will Finish Well in 1920 Race
Several Men of Major League Experience Have Signed With Birmingham.
By Tom Hanes.

Birmingham, Ala., March 6.—(Special.)—With one year checked up to experience, Carleton Molesworth’s gang of youthful pellet-jugglers is coming back to the Baronial fold Wednesday to limber up arms and limbs for the rapidly approaching mill.
Fruits of the sandlots have been plucked by the chubby chieftain and old heads on the local line-up this season will be as scarce as pork chops at a synagogue banquet.

 

LIKE A PORK CHOP IN A SYNAGOGUE

 

These are, in chronological order, the earliest occurrences of the phrase like a pork chop in a synagogue and variants that I have found:

1-: From Mack’s Raw Ones Have Proper Spirit, by Jim Nasium, published in The Philadelphia Inquirer (Philadelphia, Pennsylvania) of Wednesday 28^th July 1915:

Inhaling once more the fragrant odor of home cooking and with a lineup that looked as much out of place as a pork chop in a Jewish boarding house, Connie Mack yesterday introduced to a small but select local audience quite a bale of evidence in support of his widely discussed uplift movement by shooting in an array of talent that not only played real big league baseball, but displayed a gameness and indisposition to quit that was highly commendable.

2-: From The Gazette Times (Pittsburgh, Pennsylvania) of Sunday 15^th May 1921—the following is about the U.S. cyclist Frank Louis Kramer (1880-1958):

Frankie […] entered the six-day bicycle race at Madison Square Garden in 1912. […] All eyes were on him and his every movement was anticipated by each and every rider. Old Frankie was about as popular on that track as a pork chop at a Jewish picnic.
Toward the end of the week the viligance [sic] of all other entrants on the sprint champ began to get on his nerves and he gave up the idea of even starting a sprint, let alone winning the race. If ever anybody was “persona non grata” in an assemblage, it was Frankie Kramer.

3-: From Essendon Did Not Lie Down Says Alex Eason, who played with Footscray, published in The Sporting Globe (Melbourne, Victoria) of Saturday 1^st April 1939—the reference to Berlin is obscure:

Did Essendon lie down to Footscray when the pair met for the State Championship in 1924? Some say, and it has been written, that certain Essendon men were not trying.
For the first time we present the views of a Footscray player in that game. Alex Eason […] declares:
[…]
“Jones plays well because Tim Keary gives him the ball just where he wants it. So the other mob go out and throw a wet blanket over Keary, and Jones is snuffed out. […]
“I have seen too many men stopped by small things. A [illegible word beginning with ‘ch-’] maybe can turn only one way. The other crowd send out a cove to play him all the time from that side. He can’t get on his right leg to turn, and Jonah up the field feels like a pork chop in Berlin.”

4-: From The Mitchell Tribune (Mitchell, Indiana) of Thursday 6^th November 1958:

The Rev. and Mrs. Bill Cranford are back home this week from an unusual trip to California. They made the trip West in a Carpenter bus, which Bill drove through to Los Angeles, and returned home by train. The bus trip took 4½ days, and “wasn’t half bad,” said Bill. Mrs. Cranford was able to stretch her legs by walking around in the bus whenever she chose, but Bill had to stay behind the wheel.
On the last day of driving, Bill just pulled the throttle all the way out and “let ’er rip” (it had a governor—so it wasn’t too fast) on those long, straight Western highways. At length they reached the Los Angeles freeway, with cars going “zip-zip-zip” all around their big bus. “I felt like a pork chop at at [sic] a Jewish picnic,” says Bill.

5-: From Earl Wilson’s Broadway column, published in the Philadelphia Daily News (Philadelphia, Pennsylvania) of Saturday 8^th December 1962:

Singer Buddy Greco—a Frank Sinatra pal—opened at the Copacabana to great acclaim from the Late, Late Set. He followed brilliant singing comic George Kirby, who claimed he was “going over like a pork chop at a bar mitzvah” but was delightful.