How do we manage the safe use of residual currents?

In the Circular Connected programme, four research teams – within so-called Flagships – from Wageningen University & Research (WUR) worked together to shape the transition to a circular food system. It is an economy where organic matter forms the basis of our food system and where no more materials are wasted.

In a series of articles, the leaders of this program talk about their vision of the circular food system of the future. Bjorn Berendsen today on ‘Flagship 2: Ensuring quality and safety: how do we ensure the safety of our food and ecosystem in a circular food system? “We defined seven crucial questions to clarify the risks of using residual flows.”

Assurance of quality and safety: assurance of quality and safety
A circular food system sounds like a dream. But recycling residual streams also entails risks, such as the possible spread of bacteria or the accumulation of heavy metals. Flagship 2 therefore aims to develop a tool that provides timely control over the safe use of residual currents. Researcher Bjørn Berendsen: “Safety aspects are often only discussed after the design. We suggest starting with safety and looking at it from a ‘one health perspective’, where hazards to humans, animals and the ecosystem are weighted equally. The production of safe food should not be at the expense of the ecosystem or biodiversity.”

HACCP and more
HACCP, the standard when it comes to food risk assessment, is a good starting point. Berendsen: “With seven questions (see below), we have elaborated on HACCP, specifically aimed at residual flows. It is important to connect to existing systems. The higher the chance that people will actually use our tool. Asking these seven questions provides additional guidance in seeing the critical points of a circular system.”

Seven questions
Seven additional questions to analyze the risks of using residual flows:

  1. Which raw materials and residual streams are processed?
  2. What hazards (chemical, microbiological or physical) does the residual flow potentially entail?
  3. Can the hazards be reduced during the treatment, or can the treatment cause hazards?
  4. How are hazards transferred between spaces (e.g. from animals via manure, to soil, plant, water)?
  5. Are the hazards in the system reduced (natural mitigation) or are they persistent?
  6. Do the hazards represent a potential risk (a health perspective) in the spaces where they may occur?
  7. Are such potential risks tolerable and can they be actively mitigated, preferably at source?

Answering these seven questions sounds simple, but it certainly isn’t, emphasizes Berendsen. “In many cases, we lack the knowledge to do this because of the complexity of the food system.” The researchers distinguish between four production systems: animal, vegetable, packaging and aquaculture. What makes it so complex is that these systems are linked to circular food production. Risks therefore move throughout the food system. A hazard introduced in one place can lead to a risk elsewhere.”

Acute hazards and long-term risks
A case that accurately reflects the complexity of this research area and the current discussions around it is fertilizer. Fertilizer prevents agricultural land from being exhausted. Currently, there is sufficient organic fertilizer in the Netherlands. Fertilizer (from fossil sources) is not preferred in a circular food system. In light of the current political debate, there is a chance that the production of organic manure will decrease sharply in the future. Berendsen: “A possible alternative could be human manure, a currently unused waste stream. Then our seven core questions come into play. Because they contain, for example, pathogens or microplastics and what do we do with medicine residues? This case makes it immediately clear how much knowledge is needed to answer these questions. And how the risks move: fertilizers are applied to the soil, substances contained therein can move to groundwater and surface water or crops. To properly determine the dangers of this, we need to know exactly where residual currents go. And whether, for example, these drug residues can collect somewhere or be broken down. The whole system is connected. In this regard, we must look equally closely at acute dangers such as pathogens as well as long-term risks such as microplastics and PFAS.”

Security research contributes directly to the transition
Flagship 2 makes it clear that answering the original research question ‘how do we ensure that the safety of our food is guaranteed within a circular food system?’ is much more complex than previously thought. Berendsen: “The seven questions provide guidelines for further research. It is also important to realize that in the Netherlands the manufacturers are responsible for the safety issue. In the end, the transition also depends on the awareness of the producer.”

There is also the question of how much risk we as a society are prepared to accept. The social trend of our food is now zero. Is it realistic? And where exactly is the line? Security research can help settle this debate. Unfortunately, this often still has a negative connotation because determining a risk can hinder certain processes. But safety research can also open doors! “For example, when we can demonstrate that the use of human manure is not harmful, or how we can reduce or eliminate risks with adjustments. Then safety research contributes directly to the transition.”

Source: Wageningen University & Research

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