A recent food festival celebrating Southern California’s top restaurants has turned into a nightmare for 80 attendees who fell violently ill after attending the event.

The LA Times’ 101 Best Restaurants event, held earlier this month, brought together the region’s culinary elite, but for many, the celebration ended in painful cramps, nausea, and vomiting.

Mark Kapczynski was one of the unlucky ones. “It was pretty painful, probably the most painful experience I’ve ever had,” he recalled.

Kapczynski and his wife attended the festival, where they sampled dishes from various restaurants, including Providence, a renowned eatery serving fresh seafood.

After eating oysters from Providence, Kapczynski felt bloated immediately. By the next day, his symptoms worsened, with severe abdominal pain, chills, and discomfort.

The LA County Department of Public Health has launched an investigation into the outbreak, identifying 80 cases of norovirus infection. Emergency room physician Dr. Ali Jamehdor warned that the illness is particularly severe.

“Patients who come in after eating contaminated shellfish are very, very ill,” Dr. Jamehdor said. “Vomiting, diarrhea, significant abdominal cramping – it’s all due to a bug called vibrio, specific to oysters.”

Providence stated that the oysters were sourced from farms near Vancouver, British Columbia, Canada and that health inspectors at the event had signed off on all handling and serving regulations.

The California Department of Public Health issued a statewide alert on Canadian oysters 10 days after the event, warning that the shellfish could cause illness.

The FDA notes that people infected with norovirus can experience symptoms for 12 to 48 hours.