A comment by UC Davis professor of medicine, Dr. M. Eric Gershwin, will probably give many moms the shivers. In a CNN story today, he says that if your child's pacifier falls on the floor, put it right back in his or her mouth.

OK, that's really hard to do, but it does draw attention to his point:  The human immune system will offer a child better protection in the future if it is exposed to germs and allergens at a young age.

In the story, written by Elizabeth Landau, Gershwin called the immune system "a complicated, multiorgan, chemical and genetic nightmare" that evolved about 250,000 years ago and is unlikely to improve just by eating certain foods.

The CNN story originated at the American Association for the Advancement of Science annual meeting, being held this this week in Chicago. The article opened with futuristic musings about diets personalized for individual health profiles, saying that blanket dietary recommendations are missing the mark.

In his AAAS presentation, UC Davis food chemist Bruce German said food manufacturers' profits depend on lowering the cost of production and making their products cheaper.

"No one's getting healthy in this model," he was quoted. "It's clear we have to move toward a consumer-driven food supply."

In a consumer-driven food world, he said, the industry would focus on improving all aspects of the consumer's health. People would receive dietary recommendations based on a very specific individualized health assessment, taking into account age, sex and medical history.

A question not addressed in the story: Even if people know exactly what they should be eating, will they be willing to give up fried chicken, donuts, french fries and ice cream?