Inactivation of foodborne and other pathogenic bacteria with pyrrolidine based fatty acid amide derivatives

Authors: Olanya, Modesto; YOSIEF, HAILEMICHAEL - Former ARS Employee; Ashby, Richard - Rick; Niemira, Brendan; Sarker, Majher; Ukuku, Dike; Mukhopadhyay, Sudarsan; Msanne, Joseph; Fan, Xuetong

Submitted to: Journal of Food Safety
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/9/2023
Publication Date: 8/23/2023
Citation: Olanya, O.M., Yosief, H.O., Ashby, R.D., Niemira, B.A., Sarker, M.I., Ukuku, D.O., Mukhopadhyay, S., Msanne, J.N., Fan, X. 2023. Inactivation of foodborne and other pathogenic bacteria with pyrrolidine based fatty acid amide derivatives. Journal of Food Safety. https://doi.org/10.1111/jfs.13079.
DOI: https://doi.org/10.1111/jfs.13079

Interpretive Summary: Harmful bacteria continue to pose significant food safety risks to consumers although considerable post-harvest controls exist. There are limited published data on the application of environmentally friendly compounds to mitigate disease-causing bacterial contamination. In this research, the antibacterial properties of various fatty acid (FA) amide derivatives, produced from lauric acid (LAPY), palmitic acid (PAPY), myristic acid (MYPY) and decanoic acid (DEPY) against Listeria monocytogenes strains and other bacterial species was documented. Significant differences in the growth inhibition of Listeria, Bacillus Natto, Streptococcus sobrinus, and S. mutans were observed. Although the suppressive effects of the FA amides on bacterial populations in-vitro (disc-diffusion experiments) and their effects in co-inoculation assays varied; reductions of Listeria and other bacterial populations were concentration dependent for the limited duration of exposure time. Similarly, reductions of Listeria populations in post-harvest plant produce were recorded, following fatty acid amide derivative applications (25C). This suggests that the antibacterial activity of the fatty acid amide compounds on the Gram positive bacterial species evaluated is significant. The low toxicity of fatty acid compounds and their biodegradable nature imply that their potential applications on produce are an attractive use for post-harvest interventions.

Technical Abstract: Foodborne pathogens are a persistent threat to food and consumer safety. To mitigate outbreaks and contamination incited by these pathogens, the development of novel preventative safety controls and biorational inactivation measures are paramount. The objectives of this research were to evaluate the efficacy of pyrrolidine-based amide derivatives of decanoic (DEPY), lauric (LAPY), myristic (MYPY) and palmitic (PAPY) fatty acids for in-vitro inhibition and inactivation of various Gram-positive bacterial strains including Listeria monocytogenes (typically associated with foodborne illness), Bacillus subtilis, and Streptococcus mutans and Streptococcus sobrinus (both normally present in the oral cavity and involved with dental caries). Compared to no treatment (control), significant differences (P<0.05) in the growth of Listeria strains were seen in-vitro with increased inhibition at higher amide concentrations (10,000-20,000 ppm). Furthermore, in-vitro growth inhibition of B. subtilis, S. sobrinus, and S. mutans was also observed with an effectiveness of LAPY>MYPY>PAPY>DEPY. In co-inoculation assays, LAPY treatment significantly reduced Listeria growth from 1.55 to >5.0 Log CFU/mL when a concentration range of 5 to 250 ppm was applied. Moreover, Listeria populations on pathogen-inoculated produce were significantly (P<0.05) reduced from 0.51 to >3.00 Log CFU/g with greater inactivation on carrots compared to alfalfa, soybean, and pistachio. These results demonstrated the potential value of these FA amides against Gram-positive pathogenic bacteria. Biorational applications of antibacterial FA amides on fresh produce as a post-harvest intervention process offers a great potential for enhancement of food safety.