Antimicrobial activity of amurca (olive oil lees) extract against selected foodborne pathogens

Abstract

The antimicrobial activity of a methanolic extract of amurca (olive oil lees) was determined against both Gram-positive (L. monocytogenes and S. aureus) and Gram-negative (E. coli D157:H7 and S. enteritidis) foodborne pathogens at 10 °C or 37 °C using microdilution and disk diffusion methods, and its relative activity was compared to selected antibiotics. Minimum inhibitory (MIC) and minimum bactericidal (MBC) concentrations of amurca extract ranged from 60 to 80 µl/ml at 37 °C after 24 h against all tested strains. At 10 °C, amurca was more inhibitory with MIC and MBC values of 40 and 60 µl/ml, respectively, after 7 d against tested strains. Amurca at 40 µl/ml reduced numbers of tested pathogens by 2.5 to 3.2 log 10 CFU/ml at 10 °C after 7 d, but was not inhibitory at 37 °C after 24 h. Protein prepared from amurca was not antimicrobial. The relative antimicrobial activity (inhibition zone ratio) of 80 µl/ml amurca methanolic extract compared to chloramphenicol, erythromycin, gentamycin and tetracycline ranged from 0.36 to 1.0 against Gram-negative and from 0.45 to 2.0 against Gram-positive bacteria. In addition, amurca extract inhibited E. coli D157:H7 02-0628 and S. aureus 26127 which were resistant to tetracycline and chloramphenicol, respectively.

Impact of Olive Extract Addition on Corn Starch-Based Active Edible Films Properties for Food Packaging Applications

“…After incubation at 37 • C for 24 h, the counting of the total CFU was carried out. Positive controls were used with a concentration of 10 6 CFU mL −1 of each microorganism, following the methodology proposed by Ramirez et al [47] and Janakat et al [48].…”

Solvent extraction effects on phytochemical constituents profiles, antioxidant and antimicrobial activities and functional group analysis of Ecballium elaterium seeds and peels fruits

“…In this study, the Gram-negative isolates were less resistant to the plant extracts than the Gram-positive bacterial isolates. The higher resistance of Gram-negative bacteria could be accredited to the complexity of the double membrane including cell envelope, that be expressed by lipoprotein and lipopolysaccharide, and which plays the role of a barrier to the antibacterial substances, contrasted to the single membrane structure of Gram-positive bacteria (Zarai et al, 2012;Janakat et al, 2015). …”

Effects of metal oxide nanoparticles with plant extract on viability of foodborne pathogens

“…The dry matter of the extracts was dissolved individually at a ratio 1:2 in 4% (wt/vol) dimethyl sulfoxide (Fisher Scientific), then the solution was sterilized by filtration via 0.20 μm disposable syringe filter unit (Toyo Roshi Kaisha, Ltd., Tokyo, Japan), and collected in a sterile container for later use in the antibacterial tests (Janakat, Al‐Nabulsi, Allehdan, Olaimat, & Holley, ).…”

“…To complete the volume in the well to 250 μL, quantities of 0, 25, 50, 75, 100, and 140 μL of sterilized distilled water were added, respectively. Blank, positive, and negative controls were prepared with modification as described by Janakat et al ().…”

“…The dry matter of the extracts was dissolved individually at a ratio 1:2 in 4% (wt/vol) dimethyl sulfoxide (Fisher Scientific), then the solution was sterilized by filtration via 0.20 μm disposable syringe filter unit (Toyo Roshi Kaisha, Ltd., Tokyo, Japan), and collected in a sterile container for later use in the antibacterial tests (Janakat, Al-Nabulsi, Allehdan, Olaimat, & Holley, 2015). To determine the minimum inhibitory concentration (MIC) (the lowest concentration of material that inhibited the growth of an organism) of each extract, the samples were incubated for 24 hr at 37 C. After that, 100 μL aliquots from the samples or from their decimal dilutions were plated on tryptone soy agar (Oxoid, Ltd.) and incubated for 24 hr at 37 C.…”