Global Bugs

Monthly Archive: October 2016

Regulate the use of food waste as feed

A remarkable news item in December 2015 about researchers launching a plea for the re-legalisation of swill feed for pigs. Remarkable, as it happened in the UK, the country where swill feed caused Foot-and-Mouth Disease leading to a swill feed ban. What are the motives behind the plea?
Pigs are history’s oldest food waste recyclers. 9,000 years ago in Anatolia and the Mekong Valley, modern-day Turkey and China, wild pigs first raided the piles of food waste left by humans, taking their first steps towards domestication. Swill-feeding – cooked food waste fed to pigs is colloquially known as ‘swill’ – is a traditional recycling practice that turns discarded scraps into high-quality pork.

While swill continues to be used in small-scale pork production across much of the world, its use is controversial in some countries and there is great geographic variation in its acceptance and regulation. Swill was banned in the European Union (EU) in 2002 after the UK Foot-and-Mouth Disease (FMD) epidemic (thought to have been started by the illegal feeding of uncooked food waste to pigs), but is actively promoted in nations such as Japan, South Korea, Taiwan, and Thailand. In this article, we take a closer look at these modern East Asian systems of food waste recycling, and consider the economic and environmental case for re-legalising the use of swill in the EU.

Risk of feeding uncooked food waste to livestock
Though swill is currently illegal in the EU, this wasn’t always the case. Swill was the dominant pig feed in the early 20th century and was promoted by the UK government during the Second World War to boost food security. The popularity of swill-feeding declined after the War as the abundance of cheap grains led the pig industry to focus on increasing production efficiencies through grain- and soybean-based diets.
The risks of feeding uncooked food waste were demonstrated in 2001 when a UK farmer illegally fed some to pigs, precipitating the 2001 FMD outbreak, which cost the UK economy £8 billion (€10.4 billion). In response, swill-feeding was banned in the UK in 2001, with the ban extended across the EU the following year.

Heat treatment in Asia
While the EU saw swill only as a disease risk, other nations saw it as a potential resource. Heat treatment deactivates viruses such as FMD and Classical Swine Fever (hog cholera) and renders food waste safe for animal feed. In the same year that the UK banned the use of swill, the Japanese government launched an initiative to promote the regulated use of food waste in animal feed.

Today, Japan and South Korea recycle around 40% of their food waste as feed. In these countries, the industry is tightly regulated: the heat treatment of food waste is carried out by registered ‘Ecofeed’ manufacturers, who are required by food safety law to heat treat food waste containing meats for a minimum of 30 minutes at 70°C or 3 minutes at 80°C. Food waste feed is typically fed as a dehydrated pellet, or a fermented, liquid feed – both technologies have been shown to sterilise the food waste and increase the feed shelf life without destroying nutrients. Since the introduction of these regulated systems, there have been no swill-associated outbreaks of disease.

Swill feed may induce slower growth but also savings
In Japan and South Korea, swill is seen as a strategic resource: it is a cheap, domestic alternative to the more expensive, volatile international market for grain- and soybean-based feeds. Pigs reared on food waste produce pork of high quality – practically indistinguishable from grain-fed pork. And though swill-fed pigs tend to grow more slowly than when fed conventional, grain-based feed, (because swill has a more variable nutritional content) the costs of slower growth are more than offset by the savings in feed costs.

Swill costs half as much as grain-based feed (see Figure 1) and is popular: the use of swill has consistently grown in both countries (by 125% in Japan from 2003-2013 and by 35% in South Korea from 2001-2006).

Figure 1- Prices of conventional grain-and soybean-based pig feed and swill (Ecofeed) in Japan.

Swill feed offers EU substantial environment benefits
The switch to swill benefits not only farmers’ wallets, but also the environment. When farmers replace grain- and soybean-based feeds with swill, they reduce demand for these land- and greenhouse gas-intensive feeds. The research team at Cambridge University recently estimated what the environmental benefits would be if the EU were to introduce food waste feeding systems, like those in East Asia – and found that the benefits would be substantial. East Asian style food waste recycling would spare 1.8 million hectares of global farmland, an area half the size of Switzerland, including more than a quarter of a million hectares of Brazilian soybean. The expansion of soy in the grasslands and forests of Brazil is associated with large greenhouse gas emissions and biodiversity loss. Because of these benefits, in Japan swill-fed pork is marketed as a premium, low environmental impact product (‘Eco-pork’) and receives an associated price-premium, which further boosts farm profits.

Swill feed for poultry, fish & ruminants
While pigs have a long history of swill-feeding, food waste can, of course, be fed to other species. A number of studies have trialed food waste diets for poultry, fish, insects, and ruminants (cattle, goat and sheep). Food waste containing meats should not, however, be fed to ruminants to prevent the emergence and transmission of prion diseases, such as Bovine Spongiform Encephalopathy (BSE). In Japan and South Korea, the use of meat wastes in ruminant feed remains illegal for this reason. It is worth noting, however, that there are no recorded cases of pigs, poultry, or fish naturally developing or transmitting diseases such as BSE.

Also interesting: EU reauthorises non-ruminant PAP for fish feed
The use of non-ruminant processing animal proteins (PAP) for use exclusively for fish feed has been re-authorised by the European Commission last week.
2001 FMD outbreak resulted in swill feed ban
Whilst the disastrous FMD outbreak of 2001 showed the potential risks of feeding uncooked food waste to pigs, banning the use of swill was not the only possible solution. Nations such as Japan and South Korea offer working models for the safe, regulated use of food waste as animal feed. As the EU faces both a deficit in protein sources for animal feed and calls to create a zero-waste, circular economy, there is a growing mandate to reconsider the ban on swill. Regulating, rather than prohibiting, the use of food waste as pig feed could safely produce high-quality pork, with substantial economic and environmental benefits.

This article was published earlier online in Broadening Horizons N°22, in December 2015. The publication is a cooperation between the UN Food and Agriculture Organization (FAO) and the French National Institute for Agricultural Research (INRA).
Erasmus zu Ermgassen, Conservation Science Group, Department of Zoology, University of Cambridge, United Kingdom.


Insect sugar could treat fatty liver disease

Trehalose coaxes mouse liver cells to clear out excess fat

Cells in the body sometimes need a spring cleaning to clear out unwanted or dysfunctional proteins, fats, and other biomolecules cluttering their insides.
The regulated cleaning process cells use is called autophagy. Scientists think compounds that can trigger autophagy could lead to therapeutics for a range of diseases, including diabetes and Alzheimer’s disease, which involve the buildup of malfunctioning molecules in cells.
In a new study, researchers report that the disaccharide trehalose initiates autophagy by blocking glucose from entering cells. They show that trehalose can help liver cells in mice remove excess fat, preventing fatty liver disease in the animals (Sci. Signal. 2016, DOI: 10.1126/scisignal.aac5472).
“There are about 1 billion people walking around the world with nonalcoholic fatty liver disease, whether they know it or not,” says gastroenterologist Brian J. DeBosch of Washington University School of Medicine in St. Louis. People with the disease have excess fat in their livers, which can cause damaging inflammation and possibly lead to liver cancer or even liver failure. Currently the best treatment is diet change and weight loss.
Previous neuroscience studies pointed DeBosch and his colleagues to trehalose—a sugar made by fungi, plants, and insects—as a possible therapeutic for the disease.
Several studies have shown that the disaccharide can trigger autophagy to help neurons clear out aggregated proteins in mouse models of neurodegenerative diseases such as Alzheimer’s and amyotrophic lateral sclerosis. If trehalose could get cells to flush out built-up proteins, DeBosch and his team thought, maybe it would also help eliminate excess fat.
To test the idea, they had a group of mice drink a 3% trehalose solution for two days before putting the rodents on a diet that can induce fatty liver disease. Animals that drank the trehalose-spiked water had significantly lower levels of genetic markers for fatty liver disease, as well as lower amounts of triglycerides and cholesterol in their livers, compared with mice that didn’t consume trehalose.
Through cell culture studies, the researchers determined that trehalose inactivates glucose transporters, proteins that move glucose into cells. With less glucose coming in, cells get tricked into initiating pathways triggered by starvation, including autophagy.
These results have promising therapeutic implications because parts of the pathway trehalose turns on, in particular the activation of an enzyme called AMPK, are also stimulated by metformin, a drug that has been shown to reduce some consequences of fatty liver disease in people, says Rohit Loomba, a gastroenterologist at University of California, San Diego. Loomba thinks the researchers should next see whether trehalose can reduce biomarkers for liver inflammation and scarring, which can contribute to damage in the liver.
And neuroscientists interested in trehalose’s effects in the brain need to determine whether the sugar triggers autogaphy there through the same mechanism as in the liver, says Michel Goedert, a neurobiologist at Cambridge University, who has studied trehalose in a mouse model of Alzheimer’s disease.
The new study offers something all scientists working with trehalose have been looking for: a cellular target, says Claudio Hetz, a researcher at the University of Chile, who showed that trehalose can clear protein aggregates in mice with amyotrophic lateral sclerosis. With this protein target, scientists can possibly design molecules that are more stable and more effective autophagy activators than trehalose, he says.
But DeBosch points out that if trehalose is shown to produce similar effects in people, it would likely be well-tolerated as a therapeutic. In fact, some people already consume it. “If you look on, you can order it today and eat it tomorrow,” DeBosch says.

Source: Volume 94 Issue 9 | p. 9 | News of The Week
Issue Date: February 29, 2016 | Web Date: February 24, 2016
Chemical & Engineering News
ISSN 0009-2347
Copyright © 2016 American Chemical Society