Please login or create an account to join the discussion.

Using food waste as pig feed

Farm animals consume over a third of global crops but only deliver 12% of the world population’s calories. This is not just an inefficient use of crops but can also carry huge environmental costs when land is cleared and forests are cut down to make way for livestock feed crop production. For example, a whopping 88 % of soybeans in the UK are imported from Brazil, with virtually all of soybean meal eaten by livestock (97% globally). Possibly even more worrying is that fish that is perfectly good to be eaten by people in West Africa is taken out of local markets that cannot compete with the prices Western feed producers pay for the local catch.

No doubt this is why many people are already choosing to be vegans, vegetarians, flexitarians or ecotarians, part-time carnivores or however else we choose to label ourselves. But for those who do choose to eat meat, there is something positive that we can do too: we can ensure that the meat humankind does eat is produced with the highest welfare and lowest carbon footprint as possible. This is where ”The Pig Idea” comes in: instead of feeding virgin crops like soy, barley or maize to pigs and chickens, we should allow these omnivores to eat our leftovers, as they’ve done for thousands of years. In fact, in the UK, during both world wars leftover food was the only thing they could eat at all, as it was illegal to feed pigs any food that was deemed fit for human consumption.

Unfortunately, the 2001 outbreak of Foot and Mouth disease (FMD) led the UK to introduce an outright ban on feeding kitchen and restaurant left-overs to pigs and chickens, as well as ruminants such as cattle, followed by the EU soon after. We believe that instead of this overarching ban, it would be more sensible to bring the left-over feeding tradition into the 21st century by identifying and properly enforcing strict safety regulations and employing technology to prevent disease, thereby reducing the environmental impact of the livestock industry.

To highlight the importance of this proposal, recent research by Cambridge University (zu Ermgassen et al., 2016) concludes that changing the law and “feeding our food waste to pigs could save 1.8 million hectares of global agricultural land, including hundreds of thousands of acres of South America’s biodiverse forests and savannahs – and provide a use for the 100 million tonnes of food wasted in the EU each year.”

A further study by Salemdeeb et al. (2016) confirms that sending food waste to animal feed scores better on 12 out of 14 environmental (e.g. eutrophication and eco-toxicity) and health indicators (e.g. carcinogens) - than anaerobic digestion (biogas) or composting. The calculations in this study were based on the current UK energy mix – for the energy needed to render the food waste safe – so if renewable energy was used feed could potentially beat biogas and compost on all indicators.

Overturning the ban on the feeding of leftovers would also benefit farmers. Huge feed costs are a problem across Europe: in 2015 expenditure on feed comprised 56% of total pork production costs in the UK and as much as 65% in Ireland. Experts have commented that they believe the proportion to be over 70% in certain parts of Spain[1], now the biggest pork producer in Europe. When added to other significant costs such as housing, permits, welfare measures and veterinary services within a context of ever lower prices paid for pork, the impact of feed costs can be severe: earlier this year, 400 pigs starved to death in the Netherlands. Sadly, this is just one example of many.

Farmer organisations from across the EU are crying out about the untenable financial situation of pig producers. With high production costs and low pork prices, farmers turn to more intensive farming methods resulting in overcrowding and overuse of antibiotics which in turn may affect pig welfare standards. In contrast, sophisticated food waste-based feed producers in Japan and South Korea produce nutritious and safe pig feed from food waste at half the cost of conventional feed. The United States also has inspiring examples of converting waste food into feed, such as at Rutgers University which has been able to implement a system in its dining halls where food scraps are diverted to the nearby Pinter farm at half the cost of sending the waste to landfills (see Harvard Legal Guide: Leftovers for Livestock).

However, as Garnett (2015) points out in the description of Scenario 3 “Livestock on Leftovers” in the FCRN's Gut Feelings paper: disease risk needs to be carefully managed. While there has been no outbreak of Foot and Mouth Disease in the US since 1929 and no outbreak linked to the use of catering and retail waste in Japan, the disastrous 2001 FMD epidemic in the UK shows the critical importance of robust legislation and its effective enforcement. By robust, we do not mean an all-out ban on the feeding of any meat-containing by-products, surplus and waste food streams to all livestock, as implemented by the UK and followed soon after by European Commission. This may have been appropriate in the short term to address a disaster, but ten years after the ban, The Pig Idea campaign and others now view this as an unnecessarily heavy-handed approach (zu Ermgassen et al, 2016, Danby, 2015, Stuart, 2009).

What we propose instead is the creation of separate legislation for omnivorous non-ruminants (pigs and chickens), as these livestock naturally eat meat (and thus have high protein requirements), and have developed as human food waste recyclers throughout history. However, while we appreciate their traditional waste recycling roles, we also advocate the need for high health and safety standards enshrined in well-enforced legislation. Such legislation would be more readily enforceable in industrial centralised waste-to-feed conversion systems. Harnessing new food waste sterilisation technologies at an industrial level in the EU would also generate new jobs and investment opportunities. 

Evidence-based heat treatment specifications are central to new legislation. The UK’s Department for the Environment, Food and Rural Affairs (DEFRA) newly released study on the risks of feeding food waste to non-ruminants confirms the effectiveness of heating meat-containing surplus food to 100°C for one hour, but also highlights  the risks related to potential errors in transport, storage or manufacturing that could allow for the re-introduction of pathogens through cross-contamination between treated and untreated product. There are also some uncertainties which would benefit from further scientific input.

Within the EU Horizon2020 funded REFRESH project, Feedback is working to fully understand and mitigate this risk and propose effective risk management within a context of social, economic and environmental risk. For example, how can policy better respond to the potential risk of price hikes of agricultural commodities currently making up the key ingredients of pig and chicken feed such as soy bean and rapeseed meal, fishmeal, wheat, maize? The REFRESH project is evaluating the optimal use of food waste as animal feed alongside other innovative valorisation solutions for unavoidable food waste.  If you have any views on this risk analysis work, the uncertainties highlighted in the DEFRA study, or would be interested to discuss or collaborate on the issues discussed in this blog-post, we would be keen to hear from you.

Furthermore, together with REFRESH we will examine the acceptability of waste-fed pork to consumers, and try to better understand how the marketing of such “eco” or low “carbon hoofprint” pork would be best done. None of this is easy, but the potential environmental gains, both in terms of reduced land use change, and in terms of food waste disposal, as well as the widespread recognition that we cannot continue eating conventional high-impact animal products in current Western quantities, make this a very worthwhile task.

You can get in touch with Karen by sending her a direct FCRN member message or by email.

The views reflected in this blog-post represent the personal and professional views of the author and the author’s organisation and do not necessarily reflect the views of the European Commission or other REFRESH project partners.


Adkin, A., Harris, D. C., Reaney, S., Dewé, T., Hill, A., Crooke, H., Drew, T., Kelly, L., (2014) Assessment of risk management measures to reduce the exotic disease risk from the feeding of processed catering waste and certain other food waste to non-ruminants (Version 2.7). Department of Epidemiological Science, Animal & Plant Health Agency, Department for Environment, Food and Rural Affairs (DEFRA).

Broad Leib, E., Balkus, O., Rice, C., Maley, M., Taneja, R., Cheng, R., Civita, N., Alvoid, T. (2016) Leftovers for Livestock: A Legal Guide for Using Food Scraps as Animal Feed. Harvard Food Law and Policy Clinic, Food Recovery Project and University of Arcansas School of Law.

Danby, G. (2015) The Pig Swill Ban – A Sledgehammer to Crack a Nut? Thesis published online…

Garnett, T. (2015) Gut feelings and possible tomorrows: (where) does animal farming fit? Food Climate Research Network, Oxford Martin Programme on the Future of Food Environmental Change Institute, University of Oxford.

Salemdeeb, R., zu Ermgassen, E. K., Kim, M. H., Balmford, A., & Al-Tabbaa, A. (2016). Environmental and health impacts of using food waste as animal feed: a comparative analysis of food waste management options. Journal of Cleaner Production.

Tristram, S. (2009). Waste: Uncovering the global food scandal. Penguin.

Zu Ermgassen, E. K., Phalan, B., Green, R. E., & Balmford, A. (2016). Reducing the land use of EU pork production: where there’s swill, there’s a way. Food policy58, 35-48.


[1] Interviews by the author with academic and government experts in Spain, September 2016

Post a new comment »

Login or register to comment with your personal account. Anonymous comments require approval to be visible.