Plant bioactive compounds as an intrinsic and sustainable tool to enhance the microbial safety of crops

Authors: George, Andree; Brandl, Maria

Submitted to: Microorganisms
Publication Type: Review Article
Publication Acceptance Date: 11/26/2021
Publication Date: 11/30/2021
Citation: George, A.S., Brandl, M. 2021. Plant bioactive compounds as an intrinsic and sustainable tool to enhance the microbial safety of crops. Microorganisms. 9(12). Article 2485. https://doi.org/10.3390/microorganisms9122485.
DOI: https://doi.org/10.3390/microorganisms9122485

Interpretive Summary: Outbreaks of produce-associated foodborne illness continue to pose a threat to human health and a challenge to the produce industry. Current methods of sanitization, including chlorinated products and peracetic acid (PAA), have thus far been insufficient in fully preventing contamination of fruit and vegetables with human enteric pathogens. Therefore, additional approaches for pathogen control have become necessary. Plant innate immunity presents one such avenue for potential deactivation of enteric pathogens or inhibition of their amplification. In response to various biotic and abiotic threats, plants mount a defense response that may result in the release of reactive oxygen species (ROS) and secondary metabolites such as phenolic compounds that aim at tempering pathogen and pest attack. The antimicrobial effects of these metabolites have come under investigation as alternatives to chemical sanitization and ROS and numerous phenolic compounds are known to be effective antimicrobial compounds in vitro. Their activity against enteric pathogens in planta may provide an inherent control of their viability and further multiplication after they immigrate into the plant environment. Here we review the current state of knowledge about the effect of inhibitory plant compounds on enteric pathogen colonization of crops. Further understanding of the interplay between human pathogens and the chemical environment on/in plant hosts will likely have long lasting impacts on our management of crops to ensure enhanced produce safety.

Technical Abstract: Outbreaks of produce-associated foodborne illness continue to pose a threat to human health worldwide. New approaches are necessary to improve produce safety. Plant innate immunity has potential as a host-based strategy for the deactivation of enteric pathogens. In response to various biotic and abiotic threats, plants mount defense responses that are governed by signaling pathways. Once activated, these result in the release of reactive oxygen and nitrogen species in addition to secondary metabolites that aim at tempering microbial infection and pest attack. These phytochemicals have been investigated as alternatives to chemical sanitization, as many are effective antimicrobial compounds in vitro. Their antagonistic activity toward enteric pathogens may also provide an intrinsic hurdle to their viability and multiplication in planta. Plants can detect and mount basal defenses against enteric pathogens. Evidence supports the role of plant bioactive compounds in the physiology of Salmonella enterica, Escherichia coli, and Listeria monocytogenes as well as their fitness on plants. Here, we review the current state of knowledge of the effect of phytochemicals on enteric pathogens and their colonization of plants. Further understanding of the interplay between foodborne pathogens and the chemical environment on/in host plants may have lasting impacts on crop management for enhanced microbial safety through translational applications in plant breeding, editing technologies, and defense priming.