Jose Gavilanes and his wife typically avoid eating street food, but on Aug. 11, they wanted to enjoy the comfort food of their native country at the Ecuadorian Independence Festival on Lake Street in Minneapolis. Gavilanes ordered a plate of hornado, a slow roasted pork dish. His wife ordered a plate of potatoes with sausage.

A day later, both were ill with fevers, diarrhea and vomiting. The couple were two of more than 80 people who fell ill after eating salmonella-tainted food, including guinea pig meat, served by the festival's organizer, New York Plaza Produce.

The outbreak was the largest documented incident of food-borne illness at a single event in Minnesota since 167 prison inmates got sick in 2009, according to data from the Minnesota Department of Health. Health officials say they may never know the exact source of the contamination, because they have been unable to locate many people who didn't get sick after eating that vendor's food.

But a public health researcher said street fairs are difficult to regulate and especially vulnerable to food-borne illness. "If it's an event with a number of different vendors and diverse food, they may not all have been trained in proper preparation and food handling," said Dr. Jeff Bender, a veterinary public health professor at the University of Minnesota.

"We will never eat street food again," Gavilanes said in Spanish. "We learned that lesson."

The city of Minneapolis said last week that the vendor, Nieves Riera, whose food was the source of the salmonella, had a permit from the city to host the event and serve food, but she sold unapproved food and handled it in ways that violated the health code.

Daniel Huff, the city's director of environmental health, said Riera did not note that she would be selling guinea pig meat or pork. Other vendors did list guinea pig meat in their applications, Huff said.

On the July 16 permit application, obtained by the Whistleblower, Riera noted she expected 1,500 attendees at the festival at 1304 E. Lake St. Where the form asks whether there will be outdoor cooking and what type of food that would be served, she wrote, "Various food vendors will sell various cultural dishes." In her 2011 seasonal food vendor application, which was renewed in June, Riera said she was going to sell items such as bottled sodas, corn, cups of fruit, chicken, beans, rice and kebabs.

Riera told Whistleblower she "knows nothing" about what happened at the festival. She referred other questions to her attorney, but refused to give her attorney's name.

The event was held at Riera's New York Plaza Produce, which is regulated by the Minnesota Department of Agriculture. Last week, the store had a sign on the door saying "temporarily closed."

Food inspectors were not present at the festival, Huff said.

"Since we have events all summer long, we prioritize them," Huff said. "Just as we don't get to every restaurant every day, we don't do every event."

Josh Rounds, an epidemiologist with the Minnesota Department of Health, said that in probing outbreaks, health investigators look for unaffected people who ate food from the same supplier to narrow down the source of the contamination. But in this case, it's been difficult to find anyone who ate food from the vendor who didn't get sick, Rounds said.

"It's quite possible that we may never really know the source," Rounds said.

The Department of Agriculture said it took samples of several food products sold at the festival. Margaret Hart, a spokeswoman with the department, said inspection and complaint records from New York Plaza Produce were not immediately available.

Bender said this outbreak highlights some of the challenges in regulating street and mobile food vendors. He said this incident may have also been particularly challenging because it involved foods that may be unfamiliar to health inspectors.

Bender said the regulatory bodies, in this case the city of Minneapolis, need to have a conversation with the vendors to understand what will be on the menu, how they are preparing the food and how they plan to store and cool the food. But Bender noted that funding may be an issue.

"With an underfunded inspection unit, how many of these can you actively engage with — and especially at a cultural event?" Bender said.

Huff said he plans to meet with his staff after the investigation is complete to determine what changes can be made, including updating and revising permit applications or changing the criteria the department uses to determine which events it will inspect.

"We are always trying to figure out what is the best way we can educate folks," Huff said. "Ultimately, it's up to the people preparing food to do it correctly. … Regulators can only do so much."

Alejandra Matos • 612-673-4028 Twitter: @amatos12