Don't read this if you're about to have a good meal

By Kay Harvey
Knight Ridder News Service

You'll eat a pound of dirt in your lifetime. Most of us have heard that bit of folk wisdom. But should we believe it?

Nope. Now, the gritty truth: A pound is just the appetizer.

"We actually eat more than a pound of dirt in our lifetime," says Susan Moores, a St. Paul, Minn., dietitian and spokeswoman for the American Dietetic Association. "Probably several pounds, depending on how long an individual lives."

It's a tough thing to swallow. But the good news is dirt probably won't hurt you — depending on what you call dirt. Put it this way: Typical soil won't hurt you, say experts on soil and food. Unless it's contaminated by things you really don't want to read about over your morning coffee.

Dirt is hardly the lone substance invading our culinary turf. It's virtually impossible to get all the foreign objects out of food on its way to processing, according to the U.S. Food and Drug Administration. So, the FDA has settled on monitoring what it considers acceptable levels of unappetizing offenders.

Here's your official warning: Do not continue reading this story if you're eating.

In processed cornmeal, for example, FDA guidelines allow one or more whole insects, 50 or more insect fragments, two or more rodent hairs and one or more rodent excreta per 50 grams. In a can of peaches, 3 percent of the fruit can be moldy or wormy. And canned mushrooms will pass inspection if they have no more than an average 20 or more maggots per 100 grams.

Surprised? So was Jay Bell, now a faculty member in the University of Minnesota's College of Agriculture, when he once worked at a job counting tomatoes before they were shipped.

"It was my job to count the maggots, too," he says. "It was pretty amazing how high they'd let the number go."

But bugs and worms won't hurt you, either, he says. In many cultures, people eat insects. And in many packaged products, they are exposed to heat — which kills disease-producing organisms — during processing.

As a professor of soil science, Bell has the dirt on dirt, too. For those who don't make a distinction, he likes to establish the difference between soil and dirt.

"Soil is a living body that occurs on the surface of the Earth," he explains. "It has to be able to support plant material, and it usually has something growing in it. Once you remove it from the surface of the Earth, it's dirt. Dirt is what you have under your fingernail."

And on some of your vegetables when you pick them out at the supermarket produce counter.

Unlike soil, which is full of nutrients, dirt no longer supports organic matter so has lost most of its nutritional value. That indicates it's low in calories, if that helps anyone to better accept it as part of the standard American diet.

Some mothers have been known to tell their children not to complain about a little dirt on their veggies because dirt has minerals in it. But Bell doubts there's much nutritional value in dirt.

"Whether it's got minerals in it or not, it probably just passes through the human body," he says. "I doubt the minerals are available in a way that's going to do you much good."

Dirt is most likely to cross one's palate when eating root vegetables, especially those with crevices in them, such as potatoes and carrots, food experts say.

It's also common in leafy greens, such as lettuce and spinach, which tend to collect blowing soil and retain it when they are pulled out of the ground.

"Almost any fresh fruit or vegetable is going to catch some dirt," says Moores, the dietitian. "I made a tuna salad the other day, and the celery was just stuffed with mud." She did her best to wash the mud off, a practice she advocates.

Soil and dirt aren't the only substances that get on food. "Dirt" on food is to most people "anything we're not planning on," says Donald Vesley of the University of Minnesota School of Public Health.

He agrees that inert particles of dirt carrying nothing dangerous are probably irrelevant.

"What's of most concern would be pathogenic organisms, bacteria or viruses," he says.

Pathogens — micro-organisms able to cause disease — are the real bad guys. They can be present in raw food or make their way onto food during processing and handling.

Publicized cases of food contamination in the manufacturing, restaurant and cruise-ship industries have brought the topic of food safety to the dinner table, says Vesley, a professor in the division of environmental and occupational health.

He emphasizes the importance of hand washing before eating or preparing food; keeping kitchen tools sanitized; cooking hamburger, poultry, pork, fish and eggs thoroughly; and storing perishable foods properly.

"Keep it hot, keep it cold, or don't keep it," he advises.

But there are two schools of thought on the subject of the zealous washing of fresh fruits and vegetables. One is that ingesting normal nonfood substances can help the body build up immunities to some diseases. The other is that dirt on food can hurt you and you'd better scrub those potatoes with a vengeance.

Bell, the soil science professor, says he doesn't wash his fresh produce particularly vigorously.

"My wife does," he says. "She likes to have it as clean as possible. But I don't. I don't see a problem with it."