title: Potential Bio-Control Agent from Rhodomyrtus tomentosa against Listeria monocytogenes.
abstract: Listeria monocytogenes is an important foodborne pathogen implicated in many outbreaks of listeriosis. This study aimed at screening for the potential use of Rhodomyrtus tomentosa ethanolic leaf extract as a bio-control agent against L. monocytogenes. Twenty-two L. monocytogenes isolates were checked with 16 commercial antibiotics and isolates displayed resistance to 10 antibiotics. All the tested isolates were sensitive to the extract with inhibition zones ranging from 14 to 16 mm. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values ranged from 16 to 32 µg/mL and 128 to 512 µg/mL, respectively. Time-kill assay showed that the extract had remarkable bactericidal effects on L. monocytogenes. The extract at a concentration of 16 µg/mL reduced tolerance to 10% NaCl in L. monocytogenes in 4 h. Stationary phase L. monocytogenes cells were rapidly inactivated by greater than 3-log units within 30 min of contact time with R. tomentosa extract at 128 µg/mL. Electron microscopy revealed fragmentary bacteria with changes in the physical and morphological properties. Our study demonstrates the potential of the extract for further development into a bio-control agent in food to prevent the incidence of L. monocytogenes contamination.
authors.affiliation: Department of Microbiology, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla 90112, Thailand. odedinagrace@gmail.com.|Excellent Research Laboratory on Natural Products, Faculty of Science and Natural Product Research Center of Excellence, Prince of Songkla University, Hat Yai, Songkhla 90112, Thailand. odedinagrace@gmail.com.
authors.forename: Grace Fiyinfoluwa
authors.initials: GF
authors.lastname: Odedina
authors.affiliation: Department of Food Technology, Faculty of Agro-Industry, Prince of Songkla University, Hat Yai, Songkhla 90112, Thailand. kitiya.v@psu.ac.th.
authors.forename: Kitiya
authors.initials: K
authors.lastname: Vongkamjan
authors.affiliation: Department of Microbiology, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla 90112, Thailand. supayang.v@psu.ac.th.|Excellent Research Laboratory on Natural Products, Faculty of Science and Natural Product Research Center of Excellence, Prince of Songkla University, Hat Yai, Songkhla 90112, Thailand. supayang.v@psu.ac.th.
authors.forename: Supayang Piyawan
authors.initials: SP
authors.lastname: Voravuthikunchai
mesh_terms: D000900:Anti-Bacterial Agents / Q000302:isolation & purification / Q000494:pharmacology*; D052978:Disk Diffusion Antimicrobial Tests; D000431:Ethanol / Q000737:chemistry; D005516:Food Microbiology; D005517:Foodborne Diseases / Q000382:microbiology / Q000517:prevention & control*; D008089:Listeria monocytogenes / Q000187:drug effects* / Q000254:growth & development / Q000472:pathogenicity; D008088:Listeriosis / Q000382:microbiology / Q000517:prevention & control*; D027822:Myrtaceae / Q000737:chemistry; D008517:Phytotherapy; D010936:Plant Extracts / Q000302:isolation & purification / Q000494:pharmacology*; D018515:Plant Leaves; D010946:Plants, Medicinal; D012997:Solvents / Q000737:chemistry; D013997:Time Factors
chemical_list: D000900:Anti-Bacterial Agents; D010936:Plant Extracts; D012997:Solvents; D000431:Ethanol
keywords: Listeria monocytogenes; Rhodomyrtus tomentosa; antibacterial activity; bio-control; foodborne; salt tolerance