Is acrolein a reuterin-borne chemical hazard in biopreserved foods?

Biopreservation is defined as the use of microbes or microbially produced compounds to enhance the safety and shelf-life of food, which includes food fermentation. It is a promising and sustainable solution for alleviating microbial (fungal and bacterial) decay of foods and feeds. Food cultures, e.g., starter and adjunct cultures added as bioprotectants, contribute to food biopreservation by forming antimicrobial metabolites. Concurrently, microbial biopreservation can lead to the formation of unwanted compounds. Here we aim to highlight the critical evidence on the reactive and toxic aldehyde acrolein formation by food cultures during glycerol transformation. We name key challenges for reducing the health risk imposed by microbially derived acrolein, suggest new strategies to monitor the secondary formation of acrolein, and determine whether the levels of acrolein are high enough to cause any harm. We recommend that the release of acrolein should be considered for safety assessment of glycerol food microbes, or novel biotherapeutics are applied together. We propose to use acrolein to exemplify a framework for evaluating risk-imposing chemicals produced by food microbes, and demonstrate the needs to be addressed by scientists and policymakers to reduce the potential risk.