Four people were sickened at an Aurora Vietnamese restaurant after being exposed to E. coli.
"We want to make sure the restaurants safe and preparing food appropriately and safely for the public," said Tri-County Health epidemiologist Bernadette Albanese.
Health officials shut down the restaurant, but now Denver7 is raising questions about why it wasn't done before.
Inspection records show Pho 75 on South Havana had been cited numerous times for critical food borne illness risks.
Most often for violations like raw meat not being kept at proper temperatures or being stored above ready to eat food.
"They've had a fair number of critical violations over a period of two or three years," explained Tri-County Environmental Health Director Brian Hlavacek.
Hlavacek said unless there is a serious health hazard, like an outbreak or sewer leak the health department doesn't have the authority to shut down a restaurant, sometimes until it's too late.
"It's very difficult and very frustrating for our staff who are working with these facilities," said Hlavacek.
Tri-County Health said all four customers tested positive for E. coli O157, the same strain that hit Jack in the Box in the 1990s, killing four children.
"It’s definitely a problem, I mean this is a serious organism -- while many people do recover it's an uncomfortable illness."
One of the four customers infected is 14-year-old Noah Thompson. His father posted on Facebook that the teen was admitted to the ICU after his kidneys started failing.
"When we get cases of those, they're our priority," said Albanese.
Health officials are still trying to determine exactly what caused the outbreak, and are asking anyone who visited the Pho 75 from May 24-June 10 to fill out this confidential online survey on its website.
"What we want to do is compare foods that people ate, between people that got sick and people that didn't get sick and see if something rises to the top," she said.
As for the restaurant, Tri-County Health said it is require all staff to go through training and clean the entire restaurant before it can re-open.