Evaluation of Toxicity and Endocrine Disruption Potential of the Natural and Bio-Based Antimicrobials

Natural and bio-based antimicrobials are not usually considered safe for food application. Although many phenolics and essential oils are used as food flavoring or food ingredients, the safety of their use as natural and bio-based antimicrobials has yet to be determined and verified. Due to the wide variety of natural and bio-based antimicrobials, as well as complex biology in toxicity and endocrine disruption (ED), it is a challenge to fully evaluate the safety of food antimicrobials. One single assay or single approach is not sufficient to identify safe antimicrobials. Based on the general guidelines of the U.S. Food and Drug Administration and the National Institute of Environmental Health Sciences/National Toxicology Program, a multitiered approach is needed to investigate the toxicity and ED properties of antimicrobials. This includes both in vitro and in vivo methods. Potential toxicities of the antimicrobial compounds can be determined using human cell lines, and toxicity of the compounds on organ development of vertebrate animals can be assessed using specific pathogen-free chicken embryos. Three major methods will be introduced to determine the estrogenic activity of the antimicrobials due to the fact that estrogen signaling represents the most thoroughly studied ED activity. These three methods are: the receptor binding assay, the MCF-7 cell proliferation bioassay, and the reporter-gene assay. In this chapter, we will discuss the principles, benefits, and limitations of main assays for toxicity and ED properties as well as the related findings.