When Adonis Maracallo sat down for dinner Sunday night at the Chipotle Mexican Grill on Court Street in Brooklyn, he wasn’t thinking about E.coli.

Mr. Maracallo, 25, has been eating at Chipotle for years; he even worked at one of the chain’s stores in Manhattan. But like many customers, Mr. Maracallo decided to steer clear for a while after a string of public health scares damaged Chipotle’s reputation in 2015 and 2016, switching to Dos Toros Taqueria for his Mexican fix.

Late last year, however, Mr. Maracallo was ready to give Chipotle another chance. Now, he eats there as often as three times a week, without any concern that he might get sick.

“I loved the food,” he said. “I missed it.”

That is just what Brian Niccol, Chipotle’s chief executive, who stepped in to revive the fast-casual brand in February 2018, wants to hear. Four years after reports of E.coli and Norovirus sent customers fleeing, Chipotle has made a significant comeback. Last week, the chain’s stock price reached a high of $759, surpassing the mark it set in August 2015, not long before the crisis began.