Nearly 500 people who ate at Chipotle last year got sick. Some of those people are suing the Mexican chain.

The company will be closing all of their stores for four hours today (Monday) to hold a staff meeting about food safety. The meeting will be held at Chipotle headquarters in Denver and will be broadcast to all of the company's stores. It will be hosted by CEO Steve Ellis and will run from 11 a.m. to 3 p.m.

The meeting's purpose is to discuss an improved food safety program which includes a changes to how employees wash and cut tomatoes and lettuce, shredding cheese at a central site instead of at individual restaurants, and new ways to marinate chicken and steak.

The CDC says the outbreak which began last July appears to be over. The cause of the outbreak remains unknown.

The restaurants will re-open after the meeting.