Chipotle will be reopening 43 restaurants in Oregon and Washington without solving the E. coli problem that has left dozens of their customers sick in the past several weeks.

All in all, ABC News reported that 15 people in Oregon and another 27 in Washington have been diagnosed with E. coli infection that health officials said is probably linked to the chain, as "most" of these patients have eaten at Chipotle restaurants before reporting sick.

However, it seems that the chain is ready to reopen the 43 restaurants that they voluntarily closed last month after branches underwent strenuous cleaning processes, as well as testing and replacing their ingredients this does not guarantee that the source of the outbreak will be discovered.

The Washington Department of Health said in a statement, "Food outbreak investigations do not always identify a specific food source. A common reason for this is that the contaminated food source was consumed before the food samples were collected." USA Today reported that the Oregon Health Authority Officials reckon that the Chipotle customers were most likely sickened by contaminated produce.

Steve Ells, Chipotle chairman and co-CEO said, "The safety of our customers and integrity of our food supply has always been our highest priority. If there are any opportunities for us to do better in any facet of our sourcing or food handling -- from the farms to our restaurants -- we will find them."

He also added an apology, saying, "We are sorry to those affected by this situation, and it is our greatest priority to ensure that we go above and beyond to make certain that we find any opportunity to do better in any area of food safety."

The limited menu in Chipotle also made it difficult to pinpoint the culprit, as many of these menu items share the same ingredients. Dr William Schaffner of the Vanderbilt University Medical Center and an expert on infectious diseases said, "What you really need in order for the finger to be pointed at the source is for people to eat different things: People who eat A get sick and people eat B do not. Many of the ingredients, lettuce for example, can be on any number of different products."

He also noted that people can get infected with low-contamination as well, but in testing these food sources, the results don't always come back positive. He explained, "A lot of foodborne outbreaks are due to low-level contamination of product. The testing...and cultures come back negative and [there] could still be low-level contamination."