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Could flies fix the global food waste problem?

Black soldier flies could offer a sustainable solution for reducing food waste, research from Purdue University in the US suggests.

A research study investigating the properties of the black soldier fly in addressing food waste found that the species can be used to transform waste management and animal feeding practices to benefit the food and agricultural industries.

“There is power in these tiny soldier flies, and it is an exciting time to see the benefit we can provide to our farmers not only here in Indiana but around the world as we continue to search for ways to reduce waste safely while also producing a new protein source,” said Laura Ingwell, assistant professor of fruit and vegetable pest management in the Department of Entomology at Purdue University.

After analysing the relationship between waste reduction and livestock nutrition, Ingwell described the insects as “gamechangers” that can help find a sustainable way to support farmers and the environment.

Combating food waste is a global sustainability challenge

The United Nations Environment Programme’s (UNEP) Food Waste Index Report 2024 found that food waste has a harmful impact on the global economy and is a driver behind climate change, nature loss, and pollution.

The report found that global food waste amounted to 1.05 billion tonnes in 2022 – equivalent to almost one-fifth of all food available to the global population. In addition, 783 million people worldwide were impacted by hunger, and a third faced food insecurity.

Finding solutions to food waste to improve food security is an important global target. The UN’s Sustainable Development Goal (SDGs) 12.3 strives to achieve sustainable consumption and production patterns. By 2030, the UN aims to see the world’s food systems halve the per capita global food waste figures in the retail and consumer sectors.

Black soldier flies provide a sustainable solution to food waste

A growing body of research is tipping black soldier flies as a promising recycling agent. A 2021 study exploring the global population of the black soldier fly and its role in agriculture found the insect had potential in the insect-livestock sector.

The scientists came from worldwide institutions, including the California Department of Food and Agriculture, the University of Cambridge, and the Department of Entomology at the National Chung Hsing University, among others.

They found that the black soldier fly, officially called the Hermetia illucens, was “the most promising insect candidate for nutrient recycling through the bioconversion of organic waste into biomass”.

Researchers also found that utilising this specific fly species for agricultural purposes in the food industry enhances the sustainability of protein supplies, which could be used in the animal feed sector and help move towards a circular economy.

A novel approach to composting

Black soldier flies specifically play a beneficial role in composting. The Purdue University research into the species found that they provide a faster, safer, and more effective way to convert organic waste into valuable resources.

The fly species undergoes a complete metamorphosis and is found on every continent except Antarctica, providing an interesting and accessible food waste management option. They consume dead, decaying organic materials, consume a lot, and rapidly undertake the entire composting process.

“The amount of waste this tiny fly can produce from its work is vast,” said Ingwell.

Traditional composting, which is often used to tackle food waste, requires bacteria and fungi to break down a material’s components. However, this method does have challenges, and the researchers recommend avoiding it when composting meat, dairy, and cooked foods.

“The process is so slow that you can get harmful pathogenic bacteria present or unwanted visitors such as raccoons, skunks, and opossums pillaging the pile,” she added.

Black soldier flies work quickly to break down materials and remove pesticide and pharmaceutical residues.

“These flies eat so quickly that there isn’t an opportunity for those pathogenic bacteria or fungi to colonise,” said Ingwell. “We open a whole new world of waste solutions when introducing the black soldier fly to backyard composting and beyond.”