It’s was easier for NASA to fix the carbon dioxide problem on Apollo 13 than it is for an observer to determine the origin of a plate of cold food being picked apart with oversized tweezers by men and women in white lab coats.

Yes, another investigation is under way by the consumer advocates at the Center for Science in the Public Interest.

These are the people who informed us, thank you very much, that all the foods we love, such as egg rolls and cheese nachos and lasagna and movie theater popcorn, contain deadly calories and so much grease that if you dropped a hardened block of it on your toe, you’d probably break it. Imagine how it jams up your arteries.

These are also the people who conduct studies and brandish sound bites for deliberate headlines that appeal to the fear of the intimate enemy–the high fat and high salt–to make the point that food kills. Over the years, they’ve become experts in using the media to get a hearing. So that when they release pronouncements, they go for as big a bang as they can.

To observe the science behind their most recent investigation, an oath is taken: The type of food cannot be revealed; descriptions have to be general, and cities where meals are bought will remain anonymous until the investigators issue the results next month. “We have to preserve an embargo so we can sell the story to all the major media,” says a spokesman for the center.

And so a deal is struck, and on a humid morning in late May a journalist is escorted into a private lab in an industrial park in the Baltimore suburbs. This is where chemists can determine anything about a food, from its fat content to what kind of preservatives it has. They can even lift fingerprints off a potato. Or so they say.

Before they begin their work, the lab workers don blue rubber gloves, oversized plastic lab glasses and white coats. Their task this morning is to methodically sort, weigh and grind up 50 restaurant meals laid out on a giant metal table. The food, bought at chain restaurants in two cities, had arrived in the overnight mail in a jumble of Tupperware and plastic foam containers.