Chipotle Will Now Cook Steak Using Gourmet French Technique

— -- Another change is coming to Chipotle: how the company cooks its steaks. A Chipotle spokesperson told ABC News the company is beginning to prepare the steak used in its burritos, bowls and tacos using a French culinary technique to help prevent future pathogen outbreaks at its restaurants.

Chris Arnold, a spokesman for Chipotle, said the steak will be cooked "sous vide" at an off-site central kitchen and then marinated and seared on grills in the restaurants.

"Sous vide is a cooking technique that cooks at low temperatures over longer periods of time, and is used by a number of great chefs. If there is any difference to customers, it would be that the steak may be more tender than it was before," Arnold said.

Chipotle's steak was previously grilled in each restaurant location, according to the company website. Chipotle's beef barbacoa and pork carnitas though have long been cooked in central kitchens, Arnold said.

Last year, the Denver-based restaurant chain was hit with an E. coli outbreak that affected 53 people in nine states. Its location in Boston was forced to temporarily close after customers became ill from norovirus. On Tuesday, Chipotle announced sales fell in February and the company expects a loss of $1 a share or more in its first quarter -- the first quarterly loss for the company since it went public.

"Central cooking sounds like a much safer process," William Schaffner, a professor of infectious diseases at Vanderbilt University, told ABC News. "Pathogen testing is very elaborate, expensive and would not produce 100 percent results."

“The whole brand has to do with freshness and cooking in front of you, and [the new cooking method] is a bit in conflict with that,” Schaffner said. “But if you could get people to taste and compare the beef that was cooked centrally and beef locally, I bet people could not in a reliable fashion tell the difference using today’s technology.”

The Wall Street Journal reported yesterday that the company is considering "stepping back" from some of the food safety changes it recently implemented, including high-resolution DNA-based testing on some ingredients.

Arnold addressed The Journal's reporting, telling ABC News today, "Our commitment to establishing Chipotle as a leader in food safety remains fully intact. Over the last few months, we have implemented a number of programs and procedures to enhance food safety — including prep of some ingredients in central kitchens, high resolution testing of ingredients, and procedural changes in our restaurants. Any changes we may make to our initial plans will be to strengthen what we are doing."

On its website, Chipotle describes its high-resolution testing as "the practice of taking a large number of samples from a relatively small amount of the ingredient," which it says, for example, "substantially reduces the risk that unsafe cilantro will go undetected."

In addition to implementing changes to how its steak is prepared, Chipotle is preparing and testing tomatoes, romaine lettuce and bell peppers in its central kitchen, according to the Chipotle website. The company previously diced tomatoes at its restaurants, the company website explains.

Sam Oches, editor of Quick Service Restaurant (QSR) magazine, said he isn't surprised if Chipotle is fine-tuning its food safety process.

"With 2,000 restaurants, any decision they make is at an enormous scale," Oches said. "So you have to do it right. You have to go all in for whatever program you do."

Oches said he applauded Chipotle's move to hire a food safety czar and its decision to offer free burritos to customers last month.

"It’s hard to understate how shocking this whole thing has been because Chipotle for many years has been the gold standard," Oches said. "It’s to say this can happen to any company. There will be so many lessons learned in this. There will be textbooks written about this. Any company that wants to scale fresh locally-sourced food will have to study Chipotle. We’re watching food safety history be written."