In fact, Kurth, fresh in town from the family farm in Missouri laid low by the Depression, took a job in that mayonnaise factory; he wanted to learn how to make the stuff for his salads.
The Kurths fried fish, all right, but they were a salad powerhouse. "The whole family helped," remembers Richard Kurth, 81, Jacob's son. Tons and tons came out of the back kitchen, the homemade mayonnaise mixed with shredded cabbage, potatoes or macaroni, a mighty 1,000 pounds a night (at 7 cents a pound), sold to Brock's, the lunch vendor that serviced the factories.
It is the same-recipe salad the family makes for the platters today - the flounder platter still priced to move, at $5 - though now the mayonnaise is store-bought and delivered.
So much else has changed. The block-long trolley works is sealed up like a tomb. Where the bindery stood, grassy lots are fenced (anomalously, with wood horse-country fences) to keep out short dumpers. Elestine Ashlock plants flowers at the fences' edge.
But Kurth's endures, its witch's-hat turret askew, its sign no longer lit, the white-tile walls chipping, its exhaust hoods looming like undersea beasts. Friday nights they still line up outside, eager for fried oysters and shrimp. (Forget phoning. They take the phone off the hook when the place gets busy.)
Richard has retired. His sons, Dave (and his son Dave) and Paul, run it now, with helpers who bread the fish and make the salads and hand-cut the fries. The unflappable Cecil Byrd is at the register, and on sandwich duty - two slices of white bread, a slab of trout or flounder, hosed down with hot sauce.
The fish and the top-selling shrimp (peeled and butterflied in the back) are dipped in a powdered-egg-and-flour slurry, then in cracker crumbs, making for good crunch and a classic of the corner-joint genre.
Dave Jr. drops them in his fry basket, dumps them out on the drain rack. (They're still working on getting rid of the trans fats.) By-weight orders are weighed on old hanging scales; platters get bagged in brown paper, the tops tucked like a bedsheet.
There's another fried-shrimpery in North Philadelphia, Sid Booker's, where the shrimp is sold from a bulletproof window at the diagonal corner of Broad and Belfield.
But it's an upstart (just 41 years old) from where Kurth's stands, a proud survivor of gang wars, job flight and decline.
In the '60s, a police inspector told Richard his best move was to move out: "But you can't run," Kurth says. "You got to hang in there."
And so the Kurths have. And so have their customers, lined up, patient, and loyal to a fault.
901 W. Susquehanna Ave.
215-763-6324 (Wed.-Sat.; takeout only; closed for vacation until July 18.)
Contact columnist Rick Nichols at 215-854-2715 or email@example.com. Read his recent work at http://go.philly.com/ricknichols