FILE - In this Wednesday, Nov. 11, 2015, file photo, Rosanna Fleming enters a Chipotle restaurant for lunch as another customer enters a second door in the background in Portland, Ore. Chipotle reports financial results Tuesday, Feb. 2, 2016. (AP Photo/Don Ryan, File)

NEW YORK | Chipotle is likely to report its first quarterly decline in sales in at least a decade Tuesday after an E. coli outbreak linked to its restaurants sickened dozens of customers and damaged its reputation as a reliable place to get a fresh food.

FILE - In this Wednesday, Nov. 11, 2015, file photo, Rosanna Fleming enters a Chipotle restaurant for lunch as another customer enters a second door in the background in Portland, Ore. Chipotle reports financial results Tuesday, Feb. 2, 2016. (AP Photo/Don Ryan, File)

The Denver company warned last month that it believes sales fell 14.6 percent at established locations. It would be the first drop-off since it went public in 2006, a dramatic turn for a chain whose explosive growth is partially due to its success in positioning itself as a superior alternative to fast food.

The Centers for Disease Control and Prevention said this week that the outbreak appeared to be over and Chipotle Mexican Grill Inc., which has more than 1,900 locations, is about to launch a campaign to win back customers.

In coming weeks, Chipotle will step up advertising and roll out deals to revive sales and restore its reputation.