Chipotle Mexican Grill is trying really hard to get out of the penalty box.

Their latest effort harkens back to their heritage as a restaurant chain focused on fresh, healthy ingredients. This week, the Mexican chain announced it had finally found the right formula to eliminate all additives from its tortillas — a step that makes the restaurant preservative-free for all but its drinks.

But it remains to been seen if this new claim will be enough to erase the stigma it acquired after a string of foodborne illnesses scared people away from the chain. While Chipotle was sorting out its food safety issues, customers found other restaurant options with healthy halos, including fast casual rival Panera. So Chipotle needs to win back those diners.

What's more Chipotle may be confusing matters by quibbling over what constitutes a truly additive-free menu.

"It's going to take [Chipotle] time to get back on track," said Bonnie Riggs, an NPD Group analyst. "They still have their work cut out for them for consumers to find them trustworthy."

The focus on healthy, fresh, and "clean" food is a good start.

In January, Panera touted a claim that its menu was "100 percent clean" after having reviewed more than 450 ingredients that it sells in stores and reformulating 122 of them, including a large majority of its bakery-cafe recipes. Since then consumers have a more positive perception of Panera.

Panera continued to build on its clean menu by disclosing Friday that its soda fountains will feature signage that lists each beverage's caloric and sugar content. It will also be launching some new, low-sugar beverages.

YouGov BrandIndex, a market research firm, polled hundreds of consumers over age 18 about which brands they would consider eating the next time they went out to eat. The scores that brands receive are the percentage of respondents that said they would eat at that location the next time they went out to eat.

For Panera, that percentage score fluctuates between the high 20s and mid 30s for the general public and the mid-to-high 30s for consumers who consider themselves "healthy eaters."

In the chart below, the dark blue line represents these self-described healthy eaters, while the lighter blue line signifies the general population.