The scene: A couple of customers were eating dinner in the lounge at Ceviche in Silver Spring during a weekday. One was chowing down on Chef Javier Angeles-Beron’s ají de camarones, a Peruvian plate of breaded shrimp in yellow pepper sauce. But the diner stopped cold when he encountered a hard, sharp object. He called the waitress over to the table and asked her, more or less, What the hell is this?

“So the server came to the kitchen,” Angeles-Beron recalls. “She’s like, ‘[There’s] something on the plate. It’s like teeth. I told them it’s a [shrimp] tooth.’ I said, ‘Well, have you seen a shrimp in your life? Do you know what a shrimp looks like?’ [She says,] ‘Yeah, they kind of have this little piece in the front.’ ”

The solution: Angeles-Beron left his kitchen to investigate. He introduced himself to the guests in the lounge and asked about the shrimp. The diner, the chef remembers, said “Yeah, I found this. The server says it was the teeth of the shrimp. I was just concerned” about what kind of shrimp you’re serving. Angeles-Beron inspected the piece resting on the edge of the plate and knew immediately what it was—the corner of a plastic bag in which the shrimp are stored. “They wanted to know how plastic got into the shrimp,” he says, “So I showed them the bags.”

The bags are actually 2-pound vacuum sealed plastic containers that the line cooks snip open at the corners with scissors. They usually open the bags in the prep area, but “when we are extremely busy, sometimes they take the bag to the line,” the chef says. “They open it on the line.” One of those corners from the bag, Angeles-Beron explained to the customer, “probably fell in the sauce.”

Satisfied he wasn’t noshing on some mutant shrimp, the diner returned to his dish, which Ceviche promptly comped.