After two separate E.coli occurrences that sickened 60 customers of Chipotle Mexican Grill, the federal agency that monitors public health announced that the outbreak is now over.

The Centers for Disease Control and Prevention (CDC) said in a statement on Monday that the most recent illness in connection to the outbreak was reported last December 1.

However, the investigators also said that they still could not pinpoint a specific contaminated food or ingredient responsible for the illnesses, which occurred late last year in 14 different states. Chipotle officials even say that there could be a possibility that they may never identify what caused the sickness.

The CDC was able to confirm that 57 percent of those who were affected by the first outbreak and 80 percent of the people affected by the second were female. There were no reported deaths, but 22 of the 60 total people who became ill were confined to the hospital.

"We are pleased that the CDC has concluded its investigation, and we have offered our full cooperation throughout," Chris Arnold, a spokesman for Chipotle, said in a statement. "Over the past few months we have taken significant steps to improve the safety of all of the food we serve, and we are confident that the changes we have made mean that every item on our menu is delicious and safe."

The outbreak caused the company's stock to plunge at about 26 percent over the past three months. Chipotle's shares bounced back by 4.3 percent on Monday, closing at $472.64, after the CDC announcement. Before the health scare, their shares traded around $747.

The question remains, however: Will the restaurant's loyal customers come back, or will the outbreaks cause a permanent dent on Chipotle's reputation as an establishment that serves "food with integrity"? Only time will tell.