Bacitracin in the Food Enzyme Subtilisin: Low Levels Do Not Pose an Antimicrobial Resistance Risk

Food enzymes are essential to modern food processing, with many produced industrially through microbial fermentation. However, bacterial production strains can generate secondary metabolites, including trace amounts of antibiotics. Subtilisin, a widely used protease, is commonly produced using Bacillus paralicheniformis, a strain known to naturally synthesize bacitracin. This has raised concerns by the European Food Safety Authority (EFSA) regarding the potential contribution of subtilisin preparations to antimicrobial resistance (AMR).This review evaluates published evidence and quantitative data to assess whether to assess whether trace levels in subtilisin preparations pose an AMR risk. First, analytical data indicate that any residual bacitracin in the final enzyme preparation is extremely low and further diluted during food processing, resulting in dietary exposure well below that from permitted sources such as meat and dairy. Second, these concentrations fall far below established thresholds for selective pressure. Third, there is no robust evidence of cross-resistance to medically important antibiotics or of transferable resistance elements associated with bacitracin. Finally, bacitracin resistance genes are already widespread in the environment, including in drinking water, further diminishing the relative impact of trace exposures from food enzymes. Taken together, the evidence does not support the view that trace bacitracin in subtilisin poses a meaningful risk for the development or spread of AMR.