It is 2 p.m. on a Monday and unusually warm for October in Philadelphia. An iPod plays French music as Jihed Chehimi bumps around his station. The day usually starts at 11 a.m. or 12 p.m. “I’m always late!” he laughs. It’s a lifestyle choice. Jihed’s commute is a quick drive—probably with the windows down and Buena Vista Social Club playing—over the Walnut Street Bridge to Penn’s campus from his home in Fairmount. Late, or fashionably late, Jihed always begins his day in style, giving endless smiles and second–hand whiffs of European cologne.

There is something precise about the way he slips the blue latex gloves on his hands. It is quick, clean, automatic. After 25 years conducting lab research on viral immunology, it’s a habit. But Jihed is no longer pipetting DNA into a test tube; he traded his lab specimens for radishes and rose water. The muscle memory is obvious. Jihed glides through a baguette with his serrated knife and carefully layers salmon, radish, egg, capers and caviar, then douses it all with a squeeze of fresh lemon to create La Josie: The Swedish Salmon Smörgås.

Two years ago, Jihed walked two blocks westward from his laboratory at the Wistar Institute at 35th and Spruce Streets to begin a new experiment: Chez Yasmine Food Truck. Jihed hardly looks like your typical food truck guy. Instead, he looks like he’s ready for a vespa ride by the Seine. The slim, tanned fifty–something wears fitted jeans and an abstract–design button–up shirt. His sleek, shaved head hides behind a pair of tinted aviators. He is mysterious—like his accent, which is somewhere between French and Arabic.

Jihed was born and raised in Tunisia and received his PhD in Immunology and Infectious Disease in Paris. He came to Philadelphia in 1987 to teach at Penn's School of Medicine. In 2000, he transitioned to the Wistar to conduct grant–funded research on AIDS and Hepatitis C. When the cut–throat competition to renew grants became unbearable, he left.

Jihed and his research friends had toyed with the idea of opening a food truck before. “The friends left, but the idea didn’t,” he smiles. The small cart is nestled between Chinese and Indian, just above the Trolley stop. It is named after his daughter Yasmine—who is Tunisian and Swedish, by her mother.

It took 19 months to create the menu. According to Jihed, he “tested dishes the right way” at dinner parties. The physical truck part was not so easy, either. “For months, I could not attach the truck to my car. Every day it fell off into the middle of the street, until the Asian fruit cart guy,” Jihed points across Spruce, “taught me how to use the, quest–ce que c’est…?” Jihed does a cranking motion at his employee Seth. “A car jack? Ah yes, the car jack—but I still can’t back up!”

The real hard work is found in Jihed’s mission to create a unique culinary experience. Chez Yasmine’s menu appears more strange than his career path, because it is. It starts with the Wistar Sandwich, and features cuisine from Vietnam, Sweden and France—all the way back to Tunisian specialties. “People tell me the menu is random, but no—it it is my heritage, my story—except the grilled cheese and PB and J… they stay on the menu because they are nostalgic for my students.” He also names each item after his most loyal students, or “kids.” “Wharton students tell me it is a great marketing strategy, but I say I’m not a business person, I’m a scientist, a nerd—it’s a thank you to Chez Yasmine’s sponsors.”

Whether it is tailoring a dish to food allergies or cooking on the spot, it is always the customer and the experience that matters. “Some students can’t afford the food, but we still make it work… I don’t care about losing money. Without my students, there is no food cart.”