Feeding swill to pigs was once a widespread food recycling tradition, the tempting ingredients of which were memorialized in E.B. White's Charlotte's Web: apple parings, meat gravy, carrot scrapings, meat scraps, stale hominy and leftover "middlings" from a grain mill.

But outbreaks of livestock disease over the last decade or so has put an end to troughs of slop, and most pigs now dine on tightly controlled diets that include superfoods like soy.

In the U.K., a small group of pro-swill activists is trying to the revive the historic role of pigs as food recyclers.

Slop The Hogs

Edd Colbert, campaign coordinator of The Pig Idea, said after a foot and mouth outbreak in 2001, European Union legislators banned the use of scraps from kitchens and caterers that contain meat for livestock feed. The group wants to overturn that ban.

"Pigs can convert this food back into pork, keeping food waste in the food chain," he said.

He said in the U.K, 15 million tons of food waste is sent to landfills every year, and only one million tons of that goes to anaerobic compost, the greenest available option other than feeding people or animals.

According to the Environmental Protection Agency, the U.S. generated more than 36 million tons of food waste in 2011, 96 percent of which went to landfills or incinerators.

To promote scrap recycling, the Pig Idea is raising just eight pigs on legally available waste like grains from beer brewers, excess produce from farmers and whey from cheese makers.

The campaign will hold a pork feast in November in Trafalgar Square to cook and show off the results, including nose-to-tail oddities like head cheese, fried ears and organ "sweetbreads."

Pigs can convert this food back into pork, keeping food waste in the food chain.

Underground Swill

In the U.S., only a small number of pigs still get the kind of menu Wilbur enjoyed.

According to Michael Westendorf -- extension animal scientists at Rutgers University -- "The biggest problem with that is it contains meat. And when it contains meat it opens up a number of federal regulatory systems," he said. "If you're going to feed it to cows, everyone gets nervous because of mad cow disease."

The scraps have to be cooked and turned into swill to kill off potential pathogens. He said efforts to turn food scraps into pellets of dry feed haven't found footing.

Dining halls at Rutgers have been giving their table scraps to pig farmers for about 15 years. Farmers in New Jersey are also using feed made from scraps from casinos and prisons, gathered by garbage collectors inspired to tackle the issue.

But Westendorf said his hopes are not high that food scraps in the U.S. will be turned into large scale feed anytime soon. He said with the largest hog farms concentrated primarily in the Midwest, far from the population centers on the east and west coasts, getting the feed to the farms is a challenge. Westenddorf adds that so far, no one has been able to mass produce a viable dry feed from swill.

Too Far Afield

Changes in demographics, along with explosive growth of factory farms, have also choked off the flow of food waste to animals over the years.

Rhonda Sherman, a solid waste specialist for North Carolina State University's Cooperative Extension Service, said feeding table scraps to pigs and other animals used to be common practice in the U.S., but it's no longer practical for farmers to pick up food waste on a regular basis.

"There used to be more farmers and more rural land. Expanding cities and suburbs have put farmers farther away from where food waste is being generated," she said.

Sherman said corporate farms have strict limitations on what they feed to animals, and state laws often restrict the use of table scraps. With economic, equipment and legal limitations, the practice has lots of hurdles to clear, she said. "I'm supportive, but realistic."

Food waste has become the number one category of landfill material after massive efforts to tackle paper waste and other recyclables.

"But food waste recycling has been largely ignored until more recently," she said.

Read More:

• Why Can't Food Waste Be Fed To Pigs? (The Guardian)
• Feed Pigs Food Waste, Say Campaigners (Resource Magazine)
• Why We Rarely Feed Animals Food Scraps, Even In A Drought (NPR)