The European Food Safety Authority (EFSA) recently published a report that examines the risk assessment process of microorganisms used as pesticides. Both chemical and microbial active substances can be used as pesticides. However, they exhibit different risk profiles, as microbial active substances may produce secondary metabolites, multiply, spread, and possibly genetically adapt or transfer antimicrobial resistance (AMR) genes to other microorganisms. Therefore, there is a need to adjust the risk assessment process to address the specificities of different pesticide types. 

The European Commission’s Farm to Fork Strategy and Biodiversity Strategy for 2030 call for a 50 percent reduction in the use of and risk from chemical and other hazardous pesticides. Since the use of microorganisms as pesticides are likely to be considered as low-risk substances and may contribute to a more sustainable food system, EFSA identified the need for information about the production of secondary metabolites, as well as an investigation of national and EU integrated pest management (IPM) programs. The current report focuses on the low-risk criteria linked to AMR, the risk assessment of secondary metabolites, and the use of microorganisms in IPM programs.

The European Commission defines microorganisms as “any microbiological entity, including lower fungi and viruses, cellular or non-cellular, capable of replication or of transferring genetic material.” However, there is no standard, regulatory definition for low risk active substances. The report followed a set of exclusion criteria, set forth by the European Commission, for classifying any active substance as “low risk.” For the purposes of the report, an active substance cannot be considered low risk if it meets at least one of the following criteria:

• Carcinogenic
• Mutagenic
• Toxic to reproduction
• Sensitizing chemicals
• Toxic or very toxic
• Explosive
• Corrosive
• Neurotoxic or immunotoxic
• Disrupts endocrine system
• Persistent (half-life in soil is more than 60 days)
• Bioconcentration factor is higher than 100.

EFSA also identified two further exclusion criteria, specifically for microbial active substances: 1) demonstrates adverse effects on non-target insects for baculoviruses, and 2) demonstrates multi-drug AMR for antimicrobials used in human or veterinary medicine for other microorganisms. 

EFSA included secondary metabolites in its risk assessment framework. Secondary metabolites are related to a microorganism’s survival and ecological functions, and are not usually a cause for concern. However, some secondary metabolites may produce adverse effects that threaten animal, human, or environmental health. 

IPM, which is defined by the Food and Agriculture Organization of the United Nations as “an ecosystem approach to crop production and protection that combines different management strategies and practices to grow healthy crops and minimize the use of pesticides,” was also considered in the EFSA report. EFSA states that the use of microorganisms as pesticides is in line with several IPM principles set forth by the European Commission, as they allow for the reduction of chemical dependence in pest management. IPM principles that microbial active substances specifically address are:

• Preference to biological, physical, and non-chemical methods over chemical methods if they provide satisfactory pest control
• Preference to specific pesticides with the least side effects on human health, non-target organisms, and the environment
• Prevention of resistance development.

In its report, EFSA concluded that low-risk microorganisms are critical in achieving the goals of the Farm to Fork Strategy. Of the 65 microorganisms authorized by the European Union as active substances, 20 are currently considered low risk. However, an additional 35 microorganisms are expected to be considered as low risk, which would increase the ratio of low-risk microbial active substances to 85 percent. 

When examining the secondary metabolites of two specific microbial strains—Bacillus amyloliquefaciens and Beauvaria bassiana—EFSA was unable to procure sufficient information to draw a conclusion. However, EFSA reiterated the importance of conducting a risk assessment of the secondary metabolites produced by a given strain, as well as an evaluation of the metabolites’ toxicity. Finally, EFSA states the need to conduct projects at national and EU levels to provide suitable, sector-specific guidelines for IPM programs.