Dec. 27, 2010 -- A chef's toughest critic isn't the woman at the corner table who sent back her cod, or the man at table five nibbling on a steak tartar appetizer -- unless one of them is a Michelin inspector. Chances are, they'll never know.

The super secret spies of the restaurant industry, Michelin inspectors are the anonymous, incorruptible keepers of the coveted Michelin star rating. They've been writing anonymous reports of restaurants for over 100 years.

"We say it's a little like the CIA," said inspector "M," with a laugh. She asked that her identity not be revealed. "My whole life is staying under the radar, staying away from cameras, using fake names, trying to sneak in and out of restaurants unnoticed."

Along with their boss, Jean Luc Naret, the director of the Michelin Guide, about 90 inspectors around the world decide which restaurants will win the culinary equivalent of an Oscar, a Nobel Prize and Megamillions jackpot all at once.

"Very simple," Naret said. "There's no different type of cuisine. There's only two types -- the good one and the bad one. We only recommend the good one."

It takes years of expert training to become a Michelin inspector, many of whom come from extensive culinary backgrounds.

"Most of them have gone to culinary school or perhaps hospitality school," Naret explained. "All of them have worked in a restaurant as professional chef or in a hotel in food and beverage and, most importantly, all of them are passionate, almost obsessive foodies."

"M" said she eats out about nine times a week. Not wanting to draw attention to herself with taking notes at the table, she spends two to three hours after each meal writing extensive reports from memory.

"We have taste memories because we've eaten thousands of the same thing over and over and over again," she said. "[It] gives you a bit of a measurement to know if this is a good or less good version of something."

"It's like the Best in Show," she added. "That's what we're looking for."

If the name "Michelin" brings the tires on your car to mind, you're not too far off. The Michelin rating began in France in 1900 as a marketing gimmick to sell tires. The Michelin brothers thought their customers would burn more rubber if given a list of hotels and restaurants to explore.

Restaurants Are Reviewed Several Times and Can Lose Stars

To this day, a restaurant with a two-star rating in the Michelin Guide is noted as "worth a detour," and a restaurant with three stars, the highest rating, is noted as "worth a special journey."

The Guide covers 23 countries, and out of the 45,000 rated restaurants, less than 100 have the top rating -- only nine American restaurants carry three stars. One of those restaurants is famed French chef Eric Ripert's Le Bernardin in New York City. Ripert said he remembers the day his restaurant was awarded the three-star rating.

"I find this card on the floor," he said, pointing to a Seven of Clubs playing card. "And I said 'This is the lucky card! I'm getting three stars!'"

He said he now keeps that lucky card taped to his desk. "To remind me of that lucky day," he said.

But don't think that once the restaurant has earned a three-star rating, it can just coast along. Restaurants can still lose stars and Jean Luc Naret said when it happens, the chef usually has an excuse. Losing a rating takes more than just having a dirty fork on the table. It's about the food.

"They change the produce, the recipe, it is not as good as it used to be," Naret said. "There is always a reason, and you say 'well, I should tell you I lost my sous chef' or 'oh I should tell you I actually been sick this year,' 'I'm actually in the process of selling the restaurant,' or 'I break up with my wife,' anything can happen -- but there's always a good reason."

Naret, who will be leaving Michelin soon, said he has been seen as somewhat of a controversial figure.

"The thing I really didn't anticipate was the incredible love and hate affair that the chef has with the Michelin Guide," he said.

Critics of the Guide question the consistency of the rating system, and some have said that it has expanded too far too fast. Japan is one country critics use as an example. Shortly after Michelin arrived, Tokyo now has more three-star restaurants than Paris. Naret defended this.

Inspectors Usually Ask for a Table for One

"You have to compare apple to apple," Naret said. "There are only 15,000 restaurants in Paris. There are 160,000 restaurants in Tokyo, so obviously, more restaurants, more Michelin stars."

Inspector "M" also insisted that all Michelin stars are consistent, whether it's given to a place with placemats or white linen. She admitted being an inspector leads to a lonely dining life.

"Most of the time we dine alone," she said. "It gives us the ability to really focus on the food and the ambience and capture the entire experience."

To cover their tracks, "M" said sometimes two inspectors will dine together and write two separate papers. It's better than saying "table for one," right?

"When you're really, really into food and very passionate about food, everything else that's going on around you isn't so important," she said.