Regulatory risks associated with bacteria as biostimulants and biofertilizers in the frame of the European Regulation (EU) 2019/1009

Agriculture represents an important mechanism for the reduction in plant, animal and microbial biodiversity and the alteration of the environment. The high pressure to cope with increasing demands of food for the human population intensifies the environmental impact and requires alternative ways to produce more food and to minimize the decrease in biodiversity. The use of biostimulants and biofertilizers could represent one of such alternatives. However, we need to guarantee that their use does not result in a greater damage for human health and for the environment. The European authorities try to protect humans, plants, animals and the environment by developing the recent European Regulation (EU) 2019/1009 on biostimulants. In the present study, we discuss the taxonomic approach of the EU to limit the use of microorganisms as biostimulants. We also propose an alternative method to evaluate the safety of microorganisms that are used as biostimulants and biofertilizers. That is, we suggest the use of panels of bioassays on model organisms and potential improvements on this system to evaluate the risks associated with the use of microorganisms as biostimulants and biofertilizers. •Agriculture is a key driver of biodiversity loss.•Biostimulant microorganisms partially mitigate the damaging effect of agriculture.•The European Legislation on biostimulants is discussed.•Biosafety criteria are needed for the selection of microorganisms as biostimulants.•Biosafety measures should be based on bioassays rather than on taxonomy.