By CANDICE CHOI
AP Food Industry Writer

NEW YORK – Chipotle repeatedly told employees they need to stay home if they feel sick and the restaurant chain kept all its U.S. locations shuttered early Monday as executives went over new food safety procedures.

The presentation for workers, which comes after Chipotle has been slammed by a series of food scares, was broadcast live at hundreds of theaters and hotel conference rooms around the country.

Co-CEO Monty Moran noted that two of the four incidents had been the result of norovirus, which is typically caused by sick workers.

“If you’re feeling sick, especially if you’ve vomited, whether at work or at home, you need to let your manager or your field leader know right away,” Moran said in a broadcast from a restaurant in Denver.

With an estimated 50,000 employees in attendance to view the presentation that lasted more than an hour, Chipotle Mexican Grill Inc. postponed opening its restaurants for four hours Monday, to 3 p.m. local time.

As a peace offering to inconvenienced customers, Chipotle was offering free burritos to people who sent via text a code to the company. Moran urged employees to be “incredibly hospitable” to customers as the company pushes to win back business.

“We need you to be your very best,” he said.

Chipotle is trying to bounce back from plunging sales since an E. coli outbreak came to light in late October, and a separate norovirus incident in December. The declines have persisted, with January sales down 36 percent at restaurants open at least 13 months.

To work through the crisis, Chipotle has hired Rubenstein Public Relations, which helped organize the national worker     meeting. The Denver Company said employees watched the presentation at more than 400 locations around the country.

In New York City, employees filed into two theaters inside Regal Cinemas in Union Square. Many had orange pieces of paper on which they had been told to take notes, though that proved difficult in rooms darkened during the presentation. Employees, who were paid for attending, said they were told to come wearing their uniforms.

In a short video, employees were told to watch for symptoms such as nausea, vomiting, explosive diarrhea, yellowing of the skin and eyes and dark urine.

“When anyone vomits in the back of the house or the front line, this is a red event, which means we close the restaurant immediately,” said Gretchen Selfridge, a Chipotle restaurant support officer.

Executives also covered procedural changes that ranged from handwashing rules and the marinating of meat, to centralized locations where tomatoes and lettuce are chopped. During a brief question-and-answer period in which Chipotle selected screened questions, one employee asked whether the company planned to start chopping vegetables in restaurants again.

When the question appeared onscreen, employees in New York City groaned. One said upon leaving that cutting vegetables in stores is hard work.

How long it takes Chipotle to bounce back remains to be seen.

Other companies hit by food scares have taken about a year or more to recover, Chipotle executives note, though they acknowledge that their situation may differ because it involved more than one incident, and they received intense exposure in both social and mass media.

In the meantime, Chipotle has said it does not plan to slow down its rate of new store openings. Chipotle already has more than 2,000 locations, primarily in the U.S.