Anti-listerial activity of microalgal fatty acid methyl esters and their possible applications as chicken marinade

• Published in: International journal of food microbiology 2021-02, Vol.339, p.109027-109027, Article 109027
• Main Authors: Balakrishnan, Jeyakumar, Ganapathi, Prakash, Kannan, Suganya, Marudhamuthu, Murugan, Shanmugam, Kathiresan
• Format: Article
• Language: English
• Subjects: Algae; Animals; Anti-Bacterial Agents - pharmacology; Anti-listerial; Antibacterial activity; Aquatic microorganisms; Biofilm; Biofilms; Biofilms - drug effects; C. elegans; Cell membranes; Chicken; Chickens; Cold storage; Colonization; Cooking; Esters; Esters - pharmacology; FAMEs; Fatty acid methyl esters; Fatty acids; Fluorescence; Fluorescence microscopy; Food; Gram-negative bacteria; Intestine; Iodides; Listeria; Listeria monocytogenes; Listeria monocytogenes - drug effects; Meat; Meat - microbiology; Membrane permeability; Membrane structure; Membrane structures; Metabolism; Microalgae; Microalgae - chemistry; Microbial Sensitivity Tests; Microscopy; Minimum inhibitory concentration; Propidium iodide; Quorum sensing; Structural damage; Transmission electron microscopy
• ISSN: 0168-1605; 1879-3460
• DOI: 10.1016/j.ijfoodmicro.2020.109027

Fatty acid methyl esters (FAMEs) from marine microalgae have been reported to possess antimicrobial activities against several Gram positive and Gram negative bacteria, but a majority of them needs to be explored. The objective of this study was to investigate the antibacterial activity, mechanism of FAMEs from selected marine microalgae against Listeria monocytogenes, and to elucidate its efficacy in food model. The minimum inhibitory concentration of FAMEs was calculated to be 155 μg/mL for Chromulina sp. and 162 μg/mL for Nannochloropsis sp. against L. monocytogenes. Time-killing kinetics showed that FAMEs efficiently inhibited the growth of L. monocytogenes in a time and concentration dependent manner. The mechanism of action of FAMEs was studied by analysing its effects at a MIC on the cellular metabolism, membrane permeability, and membrane integrity of L. monocytogenes. Transmission Electron Microscopy (TEM) results showed that cells exposed to FAMEs showed damaged cell membrane structure with leakage of the internal contents in the cells of L. monocytogenes. Fluorescence microscopy images showed that L. monocytogenes cells treated with FAMEs showed high dead cell population corresponding with propidium iodide positive cells. Furthermore, FAMEs significantly down regulated quorum sensing and biofilm related genes (DegU, FlaE, and FlaD). In vivo therapeutic potential of FAMEs revealed improved Caenorhabditis elegans survival and reduced intestinal colonization during L. monocytogenes infection. Growth of listeria was abolished in chicken meat during the cold storage of 9 days when the samples were pre-treated with FAMEs. These results suggest anti-L. monocytogenes activity of FAMEs and elucidated its use in food control of chicken meat at refrigerated conditions. •FAMEs with 155 μg/mL and 155 μg/mL of MIC possess any anti-listerial activity.•In vitro, FAMEs effectively inhibited the biofilm and metabolic activity.•FAMEs attenuated quorum sensing and biofilm related genes expressions.•The non-toxic nature of FAME improved C. elegans survival against LM infection.•FAMEs as a marinade on chicken inhibited the L. monocytogenes counts.