CHICAGO – If you adjust for inflation and income, Americans have never spent less on food than they have in recent years. And yet many feel we’ve also never paid such a high price when it comes to factors other than dollars.

U.S. Department of Agriculture figures show the average American spent just 9.5 percent of his or her disposable income on food last year, a lower percentage than any country in the world.

And although meat consumption has risen slightly over the past 40 years, its impact on the pocketbook is less than half of what it was in 1970, falling from 4.1 percent to 1.6 in 2008.

The majority of this cheap protein is delivered by “factory farms” that house hundreds of animals in confinement. These concentrated animal feeding operations, or CAFOs, produce mass quantities of food at low cost.

“We have found the most efficient way to meet consumer demand for a high-quality, relatively inexpensive product,” said Dave Werner, spokesman for the National Pork Producers Council in Washington. “We’re the lowest-cost producer in the world, which is why we’re the No. 1 pork exporter in the world.”

But the system has also created disasters like August’s recall of half a billion salmonella-tainted eggs. Critics say the consolidation of food production has led to environmental damage, the loss of millions of small independent farms, rising health care expenditures and billions in tax-funded subsidies to produce cheap animal feed.

The House of Representatives held hearings last month on just what went wrong with the factory-farmed eggs implicated in the salmonella outbreak and if regulation could have helped. But many environmentalists, farmers and advocates of “sustainable” food say that, even with better regulation, this kind of agriculture is not sustainable and only artificially cheap.

“Cheap is in the eyes of the accountant,” said Daniel Imhoff, a researcher who edited the new book “CAFO: The Tragedy of Industrial Animal Factories.” “Somehow we’ve forgotten how to add the total costs of cheap meat production to our health, environment, the loss of vibrant rural communities with lots of family farms.”

The costs not calculated in the direct consumer price of meat and other animal products — called externalities — touch on a variety of issues. Among them:

HEALTH

Meat producers put antibiotics in feed to make the animals grow faster and to prevent disease. But this summer, officials from several federal agencies, including the Centers for Disease Control and Prevention, testified in support of new guidelines that would curb CAFOs’ non-therapeutic use of antibiotics, citing a rise in dangerous antibiotic-resistant infections.

The meat industry objects, saying no studies directly link drug resistance in humans to the use of antibiotics in animals.

A cheap meat supply also may affect health by encouraging people to eat more of it. Americans already eat more protein than the USDA dietary guidelines recommend — an average of 5.5 ounces of protein from meat, fish, beans and nuts combined daily. The USDA is expected to add eggs to that list of protein sources this year.

According to a recently published Harvard School of Public Health study that followed 84,000 women over 26 years, women who ate two servings per day of red meat had a 30 percent higher risk of developing coronary heart disease than those who had half a serving per day.

“So maybe it’s time to step back and ask if it really needs to be that cheap,” said David Kirby, author of “Animal Factory: The Looming Threat of Industrial Pig, Dairy and Poultry Farms to Humans and the Environment.” “Maybe we don’t need so much. Maybe we need better-quality animal products in moderation and less regularly.”

FOOD

While some CAFO supporters say these operations benefit from having enough money to hire consultants who help create safer and more efficient facilities, the multiple violations at the huge Wright County Egg operation linked to the salmonella outbreak show that larger doesn’t always mean safer.

Last year, the Consumers Union found that two-thirds of American supermarket chickens they tested were contaminated with salmonella or campylobacter, another bacterium that can sicken humans.

The relatively rapid consolidation of U.S. meat, poultry, egg and dairy production and processing greatly increases the potential for these “problems to spread fast and wide throughout the food system,” Imhoff said.

TAXPAYER DOLLARS

The meat industry doesn’t receive direct subsidies from the government. But it relies heavily on cheap corn and soy feed whose farming soaks up billions in subsidies each year. It also receives government grants for CAFO pollution management, and the government bought $150 million of pork from an industry damaged last year by swine flu fears.

ENVIRONMENT

On traditional farms, animal waste is used to fertilize crops. On CAFOs there are no crops, so an enormous amount of waste must be stored, pumped out and transported away.

Often, environmentalists say, the excrement creates toxic fumes (both while stored and when sprayed onto fields), leaks into waterways, runs off from fields and spills from lagoons and transit vehicles.

Defenders of CAFOs say environmental compliance is improving within the industry. “We support environmental standards, and problems are rare,” Werner said. “That’s not to say that there isn’t anyone out there who is not up to the standards, but that happens in every industry.”

FARMS

Representatives of the meat industry acknowledge that consolidation has led to the loss of millions of independent family farms.

Some, they note, now work as hired contractors who produce uniform animals under the rules and specifications of huge firms like Tyson or Smithfield. “As a contract grower for Smithfield, you have a guaranteed income,” Werner said.

Critics — including the USDA — say these practices put the remaining independent farmers at a disadvantage, especially when independents are given a lower price for their meat than the ones operating under contract.

ANIMAL WELFARE

Supporters of CAFOs say housing animals this way protects them from predators and harsh weather and makes it easier to feed and medicate them.

Animal rights supporters and other opponents say the crowded indoor conditions lead to stress that affects the animals’ health and increases the likelihood of mass infection. They also object to what they view as mistreatment of the animals, such as the clipping of chicken beaks to prevent closely packed birds from wounding each other.

Pastured chickens, a niche industry, are often raised in moveable outdoor pens. But Richard Lobb, spokesman for the National Chicken Council, said switching to such a system would not be feasible or wise on a large scale.

“We raise 9 billion, with a B, birds a year, and if you were to try to (pasture all the birds) in the mainstream chicken industry, you would need all of the farmland in the entire Deep South,” he said.

Many in the meat industry say CAFO practices meet consumer demand for a uniform, inexpensive product. With a record number of Americans using food stamps, cheap food strikes Lobb as a strange thing to complain about.

“Our food bill is high enough as it is,” he said. “I rejoice that there are people in this country who would be willing to pay a lot more for their food, but to me they are snobs.”

Imhoff responds that investing in more sustainable food practices would save money elsewhere.

“What we will hear time and time again from the industry is that we can’t afford to have increases in food production costs, but we haven’t tried,” he said. “And I don’t think as a society, as a country, people wouldn’t pay more if they understood what it took to make the food cheap.”

Kirby added: “It’s strange. In this country we are crazy about quality control for our kids’ toys, bedding, car seats … but then we will go out and buy the cheapest food we can find.

“This is what we put in our mouth, what we feed our children,” he said. “Why aren’t we regulating it better, and why is ‘cheap’ such an important factor?”