Transforming food waste into animal feed

Each year, one-third or more of the U.S. food supply heads to the trash. But there are plenty of solutions to cut down on food waste and its associated environmental harms. Beyond halting overproduction in farming, households and businesses can slash the amount they throw out by responsibly managing their inventory and composting food scraps. Some facilities can even turn food waste into energy.

Another solution: Turning food waste to animal feed for livestock to feast on. And while this is one of the oldest tricks in the book, making it happen has become trickier in recent decades. 

Current state of food waste and its utilization

The U.S. isn’t alone in our food waste habits. The statistics on food waste don’t lie: Most countries have a lot of work to do in terms of food waste reduction——and it’s not just a wealthy nation problem. 

Global food waste statistics

Around the world, a staggering amount of food hits the bin each year—about 1 billion tons, according to the United Nations Environment Programme.¹ While the U.S. wastes more per capita than the most of the world, China and Indonesia trail relatively closely behind. Brazil, South Africa, and Russia take the following spots.

“Food waste is a really pressing global sustainability challenge,” says Callie Babbitt, a sustainability researcher at the Rochester Institute of Technology. “We pour immense resources into the production of food—water, nutrients, chemicals, land, and a lot of energy and a lot of money goes into the production of food.”

All that uneaten grub is associated with up to 10% of the world’s greenhouse gas emissions.² That’s in part because the production, transport, and handling of food releases lots of carbon dioxide, and the waste itself spews out even more-potent methane after it’s thrown out. Beyond the environmental price, food waste and damage costs the world roughly $1 trillion per year. 

Food waste in animal feed production

People have turned food waste into animal feed for centuries, and lots of different types of industrial food waste (wheat by-products, leftovers from slaughterhouses, and even candy) can prove tasty and nutritious for animals. But in the 1980s, food waste fed to animals was linked to disease outbreaks in people—at the time, state and federal officials implemented strict laws and regulations that curtailed the practice.³ By 2007, only 3% of U.S. hog farms fed their livestock food scraps.⁴

Now, farmers, entrepreneurs and consumers around the globe want to revive the process to make it safer, more sustainable and more efficient.⁵

Benefits of transforming food waste into animal feed

Sending our meal scraps and other edible leftovers to livestock operations can directly benefit the planet and make the farming industry more sustainable.

Environmental benefits

Right now, animal feed production has a sizable carbon footprint; around 6% of all crop production emissions come from those grown for animal feed.⁶ Livestock often feast on crops like corn and barley, along with animal products such as fish oil and fish meal (around one-third of all fish caught in the world’s oceans get fed to animals).⁷ 

Most crops used as animal feed are grown solely for this purpose, and around one-third of all the planet’s cropland is dedicated to growing animal feed.⁸ Such immense crop production releases greenhouse gas emissions from sources such as farm equipment and fertilizer use, the latter of which can also pollute nearby water and air. 

By repurposing food waste for livestock meals, we can cut down on the amount of land, water, and chemicals used in raising animals and help close the loop in agriculture. And, by diverting food scraps from landfills, where they emit methane, we can also reduce additional greenhouse gas emissions.

“It’s a really smart pathway because you’re keeping that value of the food material in the food system … being able to replace those energy- and environmentally-intensive activities with a feedstock that can be processed and used to produce something with equivalent nutritional value has huge environmental savings,” Babbitt says. 

Economic advantages

Beyond its green advantages, feeding food waste to livestock can lower operational costs for farmers. The practice also offers a relatively low-cost option for businesses who want to get rid of their food waste.⁹ 

Challenges of turning food waste into feed

While repurposed food waste for livestock can play an important role in a sustainable economy, it does come with certain complexities.

Health and safety concerns

If food waste isn’t handled properly, it can pass on bacterial, parasitic, and viral diseases to animals that may make their way to humans.¹⁰ In the past, food waste fed to animals has been associated with serious outbreaks in people. For example, a neurological condition called bovine spongiform encephalopathy (commonly known as mad cow disease) may have spread when calves ate meat and bone meal made from cattle. This epidemic peaked in 1992 and killed more than 200 people as of 2019.¹¹

But these risks can be avoided by treating the feed before it’s given to animals. In the U.S., for example, food scraps derived from animals must be heated to boiling temperature (212 degrees Fahrenheit) for 30 minutes to kill off any disease-causing bacteria before the scraps get fed to pigs. U.S. law also bans tissue from mammals (like beef or pork) in feed for ruminant animals (which include cows, goats, and sheep) to prevent the spread of neurological diseases like mad cow disease.

Regulatory and quality control challenges

Beyond these federal rules, states have a dizzying range of policies on food waste in animal feed.¹² “There’s what we would call a patchwork of food waste regulations across the U.S.,” says Babbitt, “and this really affects the entire system—everything from date labeling to animal food to donations.” 

While some states have no local regulations at all, others extend the requirement for heat treatment to vegetable waste. Multiple states—including Illinois, Kentucky, Louisiana, Mississippi, and North Dakota—also prohibit all or most vegetable waste from swine feed. This is a controversial rule that some experts say should be revised due to the relatively low risks of veggie scraps. To pave the way for clearer and more uniform laws, organizations like the Zero Food Waste Coalition and ReFED offer resources for lawmakers and advocates looking to make a change.  

Innovations to transform food waste into animal feed

Despite policy challenges, researchers from around the world are looking into ways to better transform food waste that’s not fit for human consumption into animal feed. Right now, turning commercial food waste into animal feed comes with major challenges. The final product can end up with varying nutrient levels and can be pricey due to additional steps like manual waste sorting.¹³ Since food scraps have a high concentration of water, they can also break down during transportation and storage processes.

To solve these issues, scientists are looking into new techniques such as harnessing solar energy to dry out food waste to increase its shelf life and make it easier to transport to farms —while also reducing greenhouse gas emissions in the treatment process.¹⁴ 

Some researchers think insects can help transform food waste into better animal feed. Black soldier fly larvae, for instance, can munch on food waste (up to around four times their body weight per day) and help create feed that’s higher in protein than scraps alone.¹⁵ It also saves a lot of energy and space compared to other methods of animal feed production.

Startups are also getting in on the waste-to-feed action. A New England-based company called Bright Feeds runs a processing facility that uses high-tech sensors and artificial intelligence to turn commercial food waste into animal feed with a consistent amount of protein, carbohydrates, and other important components.

These innovations will require changes in U.S. state and federal law to be used on a wide scale with various types of food scraps. Overall, the complex web of food waste policy around the country generally makes it difficult to bring new technologies to ramp up processing, Babbitt says.

What are some other solutions for reducing food waste?

Sending scraps to animals is just one way to keep food out of landfills. Here are some other sustainable solutions:

Donation

The U.S. Department of Agriculture ranks food waste solutions by priority, beginning with tackling overproduction. Next up, the agency encourages redirecting excess food to people in need. Federal regulation helps protect people who donate food to nonprofit organizations from criminal and civil liability in case it, for example, makes people sick. And in January 2023, President Biden signed a law that makes it easier for businesses to donate extra food. Some states, such as Maryland, New York, and Massachusetts also have introduced financial incentives or laws to promote donation of excess foods by businesses or institutions like colleges and prisons.

Composting

Why not process food waste with nature’s recycling? By composting at home or at an industrial facility, we can create a controlled environment for tiny, hard-working organisms like bacteria, fungi, and earthworms to turn old grub into a nutrient-rich substance that helps plants thrive in soil. You can also opt for a kitchen composter from a startup called Mill that turns your food waste into chicken feed—all you have to do is send your processed scraps to the company (the bin dries out and mashes up grub into a coffee ground-like substance) and they’ll do the rest of the work.

Biogas from food waste

Our leftovers can even make a sustainable form of energy. Organic waste can be turned into all types of fuel, including methane and biodiesel, that can power wastewater treatment facilities, large vehicles, or even be sent into the broader electrical grid.

1. UNEP Food Waste Index Report 2021, United Nations Environment Programme, Mar. 2021 ↩︎
2. Ibid ↩︎
3. Leftovers for Livestock: A Legal Guide for Using Food Scraps as Animal Feed, Harvard Univ., Food Recovery Project, Univ. of Arkansas, Aug. 2016 ↩︎
4. Rules and Regulations, Federal Register, Apr. 2009 ↩︎
5. Feeding Recycled Food Waste Improved Feed Efficiency in Laying Hens from 24 to 43 Weeks of Age, Scientific Reports, May 2023 ↩︎
6. Food Production is Responsible for One-Quarter of the World’s Greenhouse Gas Emissions, Our World in Data, Nov. 2019 ↩︎
7. Forage Fish: From Ecosystems to Markets, Annual Review of Environment and Resouces, Nov. 2008 ↩︎
8. Livestock and Landscapes, Food and Agriculture Organization of the United Nations, 2012 ↩︎
9. Using Food Waste as Livestock Feed, University of Wisconsin-Extension, 2014 ↩︎
10. Microbial Health Hazards of Recycling Food Waste as Animal Feed, Future Foods, Dec. 2021 ↩︎
11. The Legacy of BSE, New Scientist, Jan. 2011 ↩︎
12. Rules are Meant to be Broken – Rethinking the Regulations on the Use of Food Waste as Animal Feed, Resources, Conservation and Recycling, Dec. 2023 ↩︎
13. Valorization of Food Waste as Animal Feed: A Step towards Sustainable Food Waste Management and Circular Bioeconomy, Animals, Apr. 2023 ↩︎
14. Drying of Food Waste for Potential Use as Animal Feed, Sustainability, May 2022 ↩︎
15. Review of Black Soldier Fly (Hermetia illucens) as Animal Feed and Human Food, Foods, Oct. 2017 ↩︎