Chipotle Mexican Grill Inc. unveiled a summer rewards program Monday aimed at winning back once-loyal customers who abandoned the fast-casual chain after a string of food safety issues was reported at locations nationwide.

The Chiptopia Summer Rewards program launches on July 1. Customers who frequent the restaurant can get as many as nine free entrees over the course of the program, which ends in September. Customers who pick up Chipotle at least 11 times per month between July and September can earn a $240 "Catering for 20" bonus reward, according to the company.

"While Chiptopia Summer Rewards lasts just three months, we will be carefully listening to our customers and using what we learn as we consider the design of an ongoing rewards program," Mark Crumpacker, chief creative and development officer at Chipotle, said in a news release.

The program rewards customers by how often they visit. Participants get rewards on their fourth, eighth and 11th visits of the month. The company is also offering bonus rewards for people who eat at the chain at least four times per month over the course of the rewards program.

Chipotle executives first brought up the idea of a temporary rewards program during an earnings call in April, Eater reported. The idea was floated as one to entice customers back to the chain, which saw E. coli and norovirus outbreaks at multiple locations in the second half of 2015. Dozens of people were also infected with salmonella after eating at Chipotle restaurants in Minnesota.

The company saw a 29.7 percent drop in same-store sales in the first quarter of 2016, according to Eater. Hit hardest was Chipotle's "most loyal" customers, "i.e. the one who visits 25 or more times per year," the food website reported.