Zov’s restaurant in Irvine was forced to shut down briefly Wednesday in the wake of a foodborne illness probe tied to four sick customers, health department officials said Thursday.

The sickened guests ate at Zov’s on Portola on three different dates between Sept. 16-22, said Deanne Thompson, a spokeswoman for the county’s Health Care Agency. All four people tested positive for shigella, an intestinal disease that triggers severe diarrhea.

Health investigators cleared Zov’s to reopen the same day after the restaurant’s owners took quick action during a four-hour closure to sanitize the restaurant and discard all ready-to-eat foods including fresh produce.

Employees, who cannot return to work until they are medically cleared by the health agency, were also given training on proper hand-washing, Thompson said.

The restaurant reopened late Wednesday using staff from the other restaurants, said Armen Karamardian, vice president of operations at Zov’s – which has locations in other parts of Orange County.

“We are reviewing all policies and procedures to ensure that such an incident will not be repeated. In 27 years of operating restaurants, this is the first such case we’ve experienced,” Karamardian said.