In a “Final Report” submitted inside the Chicago Department of Public Health, investigators determined the staple herb used in many dishes at Carbon Mexican Grill “was the most likely food-vehicle causing this outbreak.” View Full Caption DNAinfo/Ed Komenda

BRIDGEPORT — The likely cause of the summertime E. coli outbreak that sickened more than 60 people who ate at a neighborhood Mexican restaurant was cilantro, the city has ruled.

In a “Final Report” submitted by the Chicago Department of Public Health, investigators determined the staple herb used in many dishes at Carbón Live Fire Mexican Grill “was the most likely food-vehicle causing this outbreak.”

The fast-spreading E. coli outbreak was probably due to “a heavily contaminated food item” rather than an ill food worker, the report said.

Though investigators were unable to find E. coli in the cilantro or cilantro-containing food collected from the restaurant or the restaurant's distributor, the Health Department based its final report on the “strong statistical association” of raw cilantro consumption and foodborne illness, “and the high percentage of cases explained by cilantro consumption."

In foodborne illness investigations involving produce and other perishable food items, health experts say it’s often difficult to definitively identify a singular food item as the source of an outbreak.

When they can identify a specific food, though, Cilantro is a common culprit.

“Given the high probability, they’re pretty confident it was the cilantro," said Bill Marler, a Seattle-based lawyer representing more than 30 customers who said they were sickened after eating at Carbón. "Cilantro has been the source of dozens of foodbourne illness outbreaks over the years, both salmonella and E. Coli."

Read the health department's "Final Report" here:

Carbón owners have not answered requests for comment about the outbreak that forced them to cancel plans to participate in this year's Taste of Chicago festival and close both their restaurants until the Health Department completed an investigation.

During that investigation, all prepared food was thrown out, food-handling practices were reviewed, and all restaurant employees who handle food were tested at least twice for the bacteria.

Investigators collected information about restaurant employees and food preparation, copies of invoices for food items, and food samples, including steak, chicken, cilantro, elote (corn), elote mix, cheese, sour cream, grilled corn and pineapple salsa, salsa fresca, tequila lime sauce, red and green salsas.

Stool samples collected from victims revealed a toxin-producing E. coli called Shiga, a dangerous bacteria that can cause kidney failure. Victims often get sick from Shiga E. coli after eating food prepared by people who did not wash their hands well after using the bathroom.

The outbreak led Chicago resident Melissa Andrews, who spent days in the hospital after eating some of the restaurant's chicken tacos, to file a lawsuit against the restaurant. She seeks compensation for medical expenses, lost wages and her suffering.

E. coli symptoms include debilitating stomach cramps, diarrhea and vomiting. Though most cases clear up in a week, the worst of them can cause a type of kidney failure known as hemolytic uremic syndrome.

The most common form of E. coli every year causes about 96,000 illnesses, 3,200 hospitalizations and 31 deaths in the U.S., according to Food Safety News.The total number of victims in the Carbón outbreak reached 69, and 22 people were hospitalized.

On July 9, health officials cleared Carbón’s West Town restaurant to reopen at 810 N. Marshfield Ave. On July 29, the Health Department cleared the restaurant's flagship location to open.

Carbón had passed every one of nine city health inspections since 2011, according to city records. Four of those inspections happened after customers complained.

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