swine&u Gerald Shurson

Crises often lead to change. For far too long, food waste has been the greatest contributor to inefficiency of resource use and our inability to achieve greater global food security and sustainability.

More than 1.3 billion tons of edible food material are wasted annually around the world, which represents about one third of the total food produced and is enough to feed more than one billion people.

The amount and types of food waste vary between countries. Forty-four percent of global food waste occurs in less-developed countries during the post-harvest and processing stages of the food supply chain. The remaining 56 percent of these losses (of which 40 percent occur at the pre- and post-consumer stages) are attributed to developed countries in Europe, North America, Oceania, Japan, South Korea and China. As a result, the United Nations has deemed food waste reduction as a global priority and included it in the list of sustainability goals. Specifically, food waste reduction has significant implications for several of the UN Sustainable Development Goals including zero hunger; responsible consumption and production; climate action; life below water; and life on land.

Crises often accelerate existing trends and the Covid-19 pandemic is redefining the concept of sustainability. The Covid-19 pandemic has caused major disruptions in food supply chains and caused huge shifts in food access, food security and food losses due to changes in food flow and distribution patterns.

Food supply chains are complex and most operate in a “just-in-time” mode where minor disruptions can have dramatic consequences. When employees were required to stay at home, and all businesses except those deemed essential were closed, consumer demand for food shifted from food services (e.g., restaurants, hotels, schools, and institutions) to retail grocery stores. Although ample supplies of food were available, existing food distribution networks were unable to quickly respond to these changes, which resulted in increased food waste.

For example, short-term disruptions in eating habits during the early stages of the Covid-19 outbreak in Spain resulted in a 12 percent increase in food loss and waste. Furthermore, increased shortages of agricultural and food processing workers caused by illness or fear of becoming ill led to fruit and vegetable crops being destroyed, along with closures or reduced processing capacity of animal slaughter plants. This severely restricted access for market-ready livestock and poultry and resulted in the unfortunate need to humanely euthanize and dispose of millions of animals originally destined to enter the food chain.

Economic losses due to Covid-19 disruptions have been estimated to be at least $13.6 billion (U.S. dollars) for U.S. cattle producers and $5 billion for U.S. pork producers — with 30 percent less meat available to consumers at a projected 20 percent increase in price.

In addition to these economic losses, lack of sufficient rendering capacity for disposal of market-ready animals has required the use of other less-desirable methods of disposal which are detrimental to the environment and cause inefficiencies in resource use (i.e., land, water, nitrogen, phosphorus, labor) while increasing biosecurity risks.

As a result of the Covid-19 pandemic, researchers have proposed rethinking and redefining sustainability as the intersection of the economy, environment, society, and human health. Furthermore, a more holistic approach which includes climate, economics and nutrition is needed to improve food supply chain efficiency by reducing food loss and improving waste management of food supply chains adversely affected by changes in consumption patterns caused by pandemics.

In fact, the European Union has already indicated plans to revise the Farm to Fork subsection of the Green Deal reforms. Now, more than ever before, it is time for researchers and food sector experts to accelerate efforts for developing more sustainable and modern food systems by reducing the cost of food waste recovery and reutilization in the food chain. However, a very important component of food loss which has not been considered in all of these proposals, which also has dramatic effects on food security and sustainability, are mortalities caused by animal disease epidemics.

The African swine fever epidemic in China caused estimated losses of 220 to 300 million pigs originally destined for the food chain in 2019. This enormous number of pigs represents 25–35 percent of the total world pig population.

Because of the lack of infrastructure to manage the disposition of millions of pigs, the capabilities to recover nutrients from carcasses through rendering was not possible, and carcass burial and disposal in landfills were used at great environmental costs and biosecurity risks.  

In addition, highly pathogenic avian influenza outbreaks in many countries around the world have resulted in losses of millions of chickens due to mortality and depopulation.  Unfortunately, the likelihood of future disruptions in global food animal production caused by animal disease epidemics is increasing — due to increased global trade and travel, urbanization, exploitation of natural resources, and changes in land use.

These unprecedented food losses due to disruptions in global food supply chains have created an urgent need to reevaluate the intertwining of resource recovery, environmental impacts, and biosafety of various food waste streams and animal carcasses to achieve the greatest value. This is essential because animal-derived foods provide about one third of total human protein consumption; but their production requires about 75 percent of arable land and 35 percent of grain resources, while contributing about 14.5 percent to total greenhouse gas emissions.

Reimagining recovery of nutrients from food waste and animal carcasses, and subsequent recycling of these valuable nutrients into animal feed, can provide tremendous opportunities to use less arable land and rely less on global grain supplies, while reducing animal agriculture’s contribution to greenhouse gas emissions.

Although Japan and South Korea have been leaders in recycling food waste into animal feed, countries which produce much greater amounts of food waste (such as the United States and the European Union) have lagged far behind. Concerns over the risk of transmission of bacteria, prions, parasites and viruses have been the main obstacles limiting the recycling of food waste streams containing animal-derived tissues into animal feed. These concerns have led to government regulations restricting this practice in the U.S. and EU.

Adequate thermal processing is effective for inactivating all biological agents of concern — perhaps except for prions from infected ruminant tissues. The tremendous opportunity for nitrogen and phosphorus resource recovery from recycling food waste streams and rendered animal by-products into animal feed have not been fully appreciated.

Therefore, the purpose of this review is to summarize the current knowledge of the benefits and limitations of recycling various pre-harvest to post-harvest food animal-derived waste sources, as well as retail to post-consumer food waste sources, into animal feeds to achieve greater food security and sustainability.

In next month’s Swine & U, we will examine further the options for maximizing resource recovery and value of waste streams when dealing with food waste disposal.

Dr. Jerry Shurson is a Professor of swine nutrition in the University of Minnesota Department of Animal Science and can be reached at shurs001@umn.edu.