Antimicrobial activity of essential oils against foodborne multidrug-resistant enterococci and aeromonads in planktonic and biofilm state

The selection and use of natural compounds with antimicrobial activity against foodborne pathogens is of major importance. The present study evaluated the antimicrobial activity of commercial essential oils against multidrug-resistant Enterococcus spp. and Aeromonas spp. Cymbopogon flexuosus and Thymus vulgaris essential oils presented the highest inhibitory zones against both bacterial groups ( p < 0.05). Subsequent determination of the minimum inhibitory concentrations showed values between 0.47 and 1.9 mg/ml for Aeromonas spp. and from 1.9 to 15 mg/ml for Enterococcus spp. The antimicrobial effect of C. flexuosus and T. vulgaris essential oils was also assessed against biofilms. Bacteria in biofilm state were subjected to 30 min or 1 h of exposure to each essential oil and eradication ability estimated by colony counting. Both essential oils exhibited antimicrobial activity against preformed Aeromonas biofilms, but were unable to successfully eradicate biofilms produced by enterococci, in the conditions under investigation. Nonetheless, the presumptive use of essential oils in the food industry should be considered in further investigations.

Download Full-text

In Vitro Susceptibility of Multidrug Resistant Strains of Salmonella to Essential Oils

Natural Product Communications ◽

10.1177/1934578x19878904 ◽

2020 ◽

Vol 15 (1) ◽

pp. 1934578X1987890

Author(s):

Valeria Listorti ◽

Roberta Battistini ◽

Carlo Ercolini ◽

Clara Tramuta ◽

Elisabetta Razzuoli ◽

...

Keyword(s):

Antimicrobial Activity ◽

Antimicrobial Resistance ◽

Essential Oils ◽

Multidrug Resistant ◽

Animal Origin ◽

Diffusion Method ◽

Thymus Vulgaris ◽

In Vitro Susceptibility ◽

Resistant Strains

Antimicrobial resistance has become a global threat to public health. There is a critical need to find new antimicrobial substances from natural sources. The aim of this study was to investigate the antimicrobial activity of essential oils (EOs) obtained from Origanum vulgare, Thymus serpyllum, Thymus vulgaris, and Melaleuca alternifolia against multidrug resistant strains of Salmonella isolated from samples of diverse animal origin. The strains were biochemically identified, serotyped, and characterized for their antimicrobial resistance profiles. The antimicrobial activity of the EOs against the strains was evaluated using the Kirby-Bauer diffusion method, followed by determination of the minimal inhibitory concentration and minimum bactericidal concentrations. The EOs of T. serpyllum and O. vulgare, which contain carvacrol as the main compound, show excellent antimicrobial activity.

Download Full-text

Thymus vulgaris (red thyme) and Caryophyllus aromaticus (clove) essential oils to control spoilage microorganisms in pork under modified atmosphere

Italian Journal of Food Safety ◽

10.4081/ijfs.2016.5785 ◽

2016 ◽

Vol 5 (3) ◽

Cited By ~ 2

Author(s):

Serena D'Amato ◽

Giovanni Mazzarrino ◽

Chiara Rossi ◽

Annalisa Serio ◽

Clemencia Chaves López ◽

...

Keyword(s):

Antimicrobial Activity ◽

Essential Oils ◽

Antimicrobial Effect ◽

Alternative Methods ◽

Thymus Vulgaris ◽

Meat Production ◽

Modified Atmosphere ◽

Fresh Meat ◽

The Matrix

In recent years, it has been confirmed that essential oils (EOs) exert antimicrobial activity as they are able to inhibit cell growth and inactivate microbial cells. The application of biopreservation strategies by means of EOs opens up interesting perspectives in the food industry, including meat production. The paper aims to evaluate the effects of Thymus vulgaris (red thyme) and Caryophyllus aromaticus (cloves) EOs on the development of the spoilage population of fresh pork packaged under modified atmosphere (MAP). In particular, the research was focused on Brochothrix thermosphacta, a specific spoilage microorganism of fresh meat packed in anaerobic conditions or under MAP. Amongst seven EOs, those that showed the highest antimicrobial activity on 5 B. thermosphacta strains in vitro were: cloves [minimum inhibitory concentration (MIC) 0.6-2.5 mg/mL], savory (MIC 2.5-5.0 mg/mL), and red thyme (MIC 2.5 to 20 mg/mL). Red thyme and cloves EOs were selected for meat treatment, by increasing the dose at 20 and 40 mg/mL respectively, to take into account the matrix effect that can reduce EO availability. In spite of the minor efficacy observed in vitro, 40 mg/mL red thyme EO strongly limited the growth of B. thermosphacta in pork samples up to day 6 of storage [below 3.0 Log colony forming unit (CFU)/g, starting from 2.0 Log CFU/g at time 0], and exerted an antimicrobial effect also on the aerobic mesophilic count. Good results were obtained also with 20 mg/mL red thyme EO. The control of B. thermosphacta growth through EOs encourages research on alternative methods for extending the shelf life of fresh meat under MAP.

Download Full-text

Chemical Composition and Antimicrobial Activity of Cinnamon, Thyme, Oregano and Clove Essential Oils Against Plant Pathogenic Bacteria

Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis ◽

10.11118/actaun201765041129 ◽

2017 ◽

Vol 65 (4) ◽

pp. 1129-1134 ◽

Cited By ~ 5

Author(s):

Matěj Božik ◽

Pavel Nový ◽

Pavel Klouček

Keyword(s):

Antimicrobial Activity ◽

Chemical Composition ◽

Essential Oils ◽

Pathogenic Bacteria ◽

Antimicrobial Agents ◽

Antimicrobial Effect ◽

Fruit Trees ◽

Thymus Vulgaris ◽

Syzygium Aromaticum ◽

Plant Pathogenic Bacteria

Essential oils are volatile substances from plants and many of them have antimicrobial activity. For that reason, they have become known as a useful alternative to chemical preservatives and pesticides. In this study, we tested essential oils of four aromatic plants. Cinnamon (Cinnamomum zeylanicum), thyme (Thymus vulgaris), oregano (Origanum vulgare) and clove (Syzygium aromaticum) essential oils were investigated for their composition and antimicrobial effect against plant pathogenic bacteria (Pectobacterium spp. and Pseudomonas spp.). Both are commonly associated with diseased fruit trees in orchards and gardens. The chemical composition of the tested essential oils was identified by gas chromatography coupled with mass spectrometry. The cinnamon essential oil was most effective form tested oil. The experimental results indicated that the wild strains of tested bacteria are more resistant to essential oils than commonly used laboratory strains. In conclusion, certain essential oils could be used for the control of postharvest bacterial pathogens. The findings of the present study suggest that the essential oils have a potential to be used as antimicrobial agents.

Download Full-text

Synergistic Activity of Essential Oils from Herbs and Spices Used on Meat Products against Food Borne Pathogens

Natural Product Communications ◽

10.1177/1934578x1701200236 ◽

2017 ◽

Vol 12 (2) ◽

pp. 1934578X1701200 ◽

Cited By ~ 1

Author(s):

Juan García-Díez ◽

Joana Alheiro ◽

Ana Luisa Pinto ◽

Virgilio Falco ◽

Maria João Fraqueza ◽

...

Keyword(s):

Antimicrobial Activity ◽

Essential Oils ◽

Foodborne Pathogens ◽

Meat Products ◽

Antimicrobial Effect ◽

Synergistic Activity ◽

High Concentration ◽

Salmonella Spp ◽

The Individual ◽

Herbs And Spices

Essential oils (EOs) could be utilized as natural agents to improve the safety of meat products. However, the high concentration required to achieve an antimicrobial effect in foods might be incompatible with their sensory acceptance. To avoid this problem, combinations of EOs provide an effective approach reducing the odds of sensory rejection. In our study, 13 EOs of herbs and spices commonly used in the seasoning of meat products were assessed for their antimicrobial activity against Salmonella spp., Listeria monocytogenes, Escherichia coli and Staphylococcus aureus. However, only 7 of them were selected to study their synergistic effect based on their antimicrobial activity and minimum inhibitory concentration (MIC) against foodborne pathogens. EOs of thyme and cinnamon presented the largest antibacterial activity against foodborne pathogens. Combinations of selected EOs displayed a synergic effect against foodborne pathogens and also an important decrease in their individual MIC. Thyme EO presented the lowest individual MIC, but its utilization in combination decreased the MIC of the other EOs. Utilization of cinnamon EO also improved the reduction of the individual MICs of the EOs of cumin and parsley. Our results suggest the potential use of EO mixtures to control foodborne pathogens in meat products. Although the individual MIC values of selected EOs decreased, the sensory impact on meat products needs to be assessed.

Download Full-text

In vitro activity of essential oils against Pseudomonas aeruginosa isolated from infected hip implants

The Journal of Infection in Developing Countries ◽

10.3855/jidc.10988 ◽

2018 ◽

Vol 12 (11) ◽

pp. 996-1001 ◽

Cited By ~ 11

Author(s):

Veronica Amorese ◽

Matthew Donadu ◽

Donatella Usai ◽

Angelino Sanna ◽

Fabio Milia ◽

...

Keyword(s):

Antimicrobial Activity ◽

Essential Oils ◽

Antimicrobial Properties ◽

Multidrug Resistant ◽

Thymus Vulgaris ◽

Hip Implants ◽

Melaleuca Alternifolia ◽

New Antibiotics ◽

Normal Human

Introduction: Essential oils have been used since ancient times and are known for their anti-inflammatory, anti-depressive, antiseptic, antifungal and antimicrobial properties. Methodology: in this study the antimicrobial activity of two essential oils from Melaleuca alternifolia and Thymus vulgaris–red thyme geraniol was tested against 16 multidrug-resistant P. aeruginosa strains from infected hip implants as well as the “in vitro” cytotoxic activity on normal human Wong-Kilbourne derivative (WKD) cells. Results: Thymus vulgaris–red thyme geraniol showed lower antimicrobial activity when compared to Melaleuca alternifolia. All tested oils were cytotoxic at concentrations lower than 0.12%. Conclusion: Increase in drug resistance and lack of new antibiotics may encourage the development of natural treatments together with higher concern on environmental issues and natural lifestyle.

Download Full-text

Chemical composition and antimicrobial activity of essential oils from selected herbs cultivated in the South of Brazil against food spoilage and foodborne pathogens

Ciência Rural ◽

10.1590/s0103-84782012000700026 ◽

2012 ◽

Vol 42 (7) ◽

pp. 1300-1306 ◽

Cited By ~ 33

Author(s):

Sheila Mello da Silveira ◽

Anildo Cunha Júnior ◽

Gerson Neudí Scheuermann ◽

Fábio Luiz Secchi ◽

Cleide Rosana Werneck Vieira

Keyword(s):

Antimicrobial Activity ◽

Chemical Composition ◽

Essential Oils ◽

Foodborne Pathogens ◽

Disc Diffusion ◽

Bacterial Strains ◽

Plant Essential Oils ◽

Agar Disc ◽

Cymbopogon Flexuosus ◽

South Of Brazil

The chemical composition of 10 selected plant essential oils obtained by steam distillation was determined by GC and GC/MS. The antimicrobial activity of the essential oils was screened against 12 important food-related bacterial strains by agar disc-diffusion assay. MIC and MBC were determined for the essential oils that presented the highest activity in the agar disc-diffusion test. The most active essential oils against the tested bacteria were, in descending order, lemongrass (Cymbopogon flexuosus), basil (Ocimum basilicum), oregano (Origanum vulgare), cinnamon leaf (Cinnamomum zeylanicum), and laurel (Laurus nobilis). Except for S. Typhimurium, the tested bateria were inhibited at MIC values lower or equal to 0.62mg mL-1 by lemongrass (Cymbopogon flexuosus) essential oil. Yersinia enterocolitica presented the highest sensitivity to all essential oils tested (CMI≤0.62mg mL-1). There was a significant correlation (P<0.05) between oxygenated monoterpenes levels in the essential oils and MIC and MBC values against Escherichia coli. Results showed that the evaluated essential oils present high potential as natural preservatives.

Download Full-text

Synergistic Antimicrobial Activities of Combinations of Vanillin and Essential Oils of Cinnamon Bark, Cinnamon Leaves and Cloves

Foods ◽

10.3390/foods10061406 ◽

2021 ◽

Vol 10 (6) ◽

pp. 1406

Author(s):

Rita Cava-Roda ◽

Amaury Taboada-Rodríguez ◽

Antonio López-Gómez ◽

Ginés Benito Martínez-Hernández ◽

Fulgencio Marín-Iniesta

Keyword(s):

Antimicrobial Activity ◽

Essential Oils ◽

Food Packaging ◽

Antimicrobial Effect ◽

Antimicrobial Activities ◽

Inhibitory Effects ◽

Cinnamon Bark ◽

E Coli ◽

Pure Compounds ◽

Main Component

Plant bioactive compounds have antimicrobial and antioxidant activities that allow them to be used as a substitute for synthetic chemical additives in both food and food packaging. To improve its sensory and bactericidal effects, its use in the form of effective combinations has emerged as an interesting possibility in the food industry. In this study, the antimicrobial activities of essential oils (EOs) of cinnamon bark, cinnamon leaves, and clove and the pure compounds vanillin, eugenol, and cinnamaldehyde were investigated individually and in combination against Listeria monocytogenes and Escherichia coli O157:H7. The possible interactions of combinations of pure compounds and EOs were performed by the two-dimensional checkerboard assay and isobologram methods. Vanillin exhibited the lowest antimicrobial activity (MIC of 3002 ppm against L. monocytogenes and 2795 ppm against E. coli O157:H7), while clove and cinnamon bark EOs exhibited the highest antimicrobial activity (402–404 against L. monocytogenes and 778–721 against E. coli O157:H7). For L. monocytogenes, pure compound eugenol, the main component of cinnamon leaves and clove, showed lower antimicrobial activity than EOs, which was attributed to the influence of the minor components of the EOs. The same was observed with cinnamaldehyde, the main component of cinnamon bark EO. The combinations of vanillin/clove EO and vanillin/cinnamon bark EO showed the most synergistic antimicrobial effect. The combination of the EOs of cinnamon bark/clove and cinnamon bark/cinnamon leaves showed additive effect against L. monocytogenes but indifferent effect against E. coli O157:H7. For L. monocytogenes, the best inhibitory effects were achieved by cinnamon bark EO (85 ppm)/vanillin (910 ppm) and clove EO (121 ppm)/vanillin (691 ppm) combinations. For E. coli, the inhibitory effects of clove EO (104 ppm)/vanillin (1006 ppm) and cinnamon leaves EO (118 ppm)/vanillin (979 ppm) combinations were noteworthy. Some of the tested combinations increased the antimicrobial effect and would allow the effective doses to be reduced, thereby offering possible new applications for food and active food packaging.

Download Full-text

Chemical Composition, Antioxidant and Antibacterial Activity of Bunium persicum, Eucalyptus globulus, and Rose Water on Multidrug-Resistant Listeria Species

Journal of Evidence-Based Integrative Medicine ◽

10.1177/2515690x17751314 ◽

2018 ◽

Vol 23 ◽

pp. 2515690X1775131 ◽

Cited By ~ 7

Author(s):

Farhad Sharafati Chaleshtori ◽

Mohamad Saholi ◽

Reza Sharafati Chaleshtori

Keyword(s):

Antimicrobial Activity ◽

Antibacterial Activity ◽

Essential Oil ◽

Essential Oils ◽

Eucalyptus Globulus ◽

Multidrug Resistant ◽

Bacterial Strains ◽

Antioxidant Power ◽

Listeria Species ◽

Bunium Persicum

This research was aimed at investigating the antioxidant and antibacterial activity of Bunium persicum, Eucalyptus globulus, and rose water on multidrug-resistant Listeria species. The antibiotic resistance of Listeria spp obtained from seafood samples were determined by the Kirby-Bauer method. The antioxidant and antibacterial activity of the essential oils and extracts were evaluated using ferric reducing antioxidant power and microdilution methods, respectively. A total 2 samples (1.88%) were positive for Listeria spp. L monocytogenes was found to be resistant to ampicillin, amoxicillin/clavulanic acid, penicillin, vancomycin, and kanamycin. B persicum essential oil showed the greatest antioxidant activity (248.56 ± 1.09 µM Fe2+/g). The E globulus essential oil showed consistently strong antimicrobial activity against L monocytogenes and L grayi, while rose water showed no antimicrobial activity against any of the tested bacterial strains. The results showed that after adding the B persicum and E globulus essential oils to bacteria, the cell components’ release increased significantly.

Download Full-text

Essential Oils of Aromatic Plants with Antibacterial, Anti-Biofilm and Anti-Quorum Sensing Activities against Pathogenic Bacteria

Antibiotics ◽

10.3390/antibiotics9040147 ◽

2020 ◽

Vol 9 (4) ◽

pp. 147 ◽

Cited By ~ 5

Author(s):

Marlon Cáceres ◽

William Hidalgo ◽

Elena Stashenko ◽

Rodrigo Torres ◽

Claudia Ortiz

Keyword(s):

Escherichia Coli ◽

Antimicrobial Activity ◽

Quorum Sensing ◽

Essential Oils ◽

Pathogenic Bacteria ◽

Bacterial Resistance ◽

Thymus Vulgaris ◽

Dependent Manner ◽

Concentration Dependent Manner ◽

Biofilm Inhibition

Both the ability of bacteria to form biofilms and communicate through quorum sensing allows them to develop different survival or virulence traits that lead to increased bacterial resistance against conventional antibiotic therapy. Here, seventeen essential oils (EOs) were investigated for the antimicrobial, antibiofilm, and anti-quorum sensing activities on Escherichia. coli O157:H7, Escherichia coli O33, and Staphylococcus epidermidis ATCC 12228. All essential oils were isolated from plant material by using hydrodistillation and analyzed by GC-MS. The antimicrobial activity was performed by using the microdilution technique. Subinhibitory concentrations of each EO were assayed for biofilm inhibition in both bacterial strains. Quantification of violacein in Chromobacterium violaceum CV026 was performed for the anti-quorum sensing activity. The cytotoxicity activity of the EOs was evaluated on Vero cell line by using MTT method. Thymol-carvacrol-chemotype (I and II) oils from Lippia origanoides and Thymus vulgaris oil exhibited the higher antimicrobial activity with MIC values of 0.37–0.75 mg/mL. In addition, these EOs strongly inhibited the biofilm formation and violacein (QS) production in a concentration-dependent manner, highlighting thymol-carvacrol-chemotype (II) oil as the best candidate for further studies in antibiotic design and development against bacterial resistance.

Download Full-text

Allium sativum, Rosmarinus officinalis, and Salvia officinalis Essential Oils: A Spiced Shield against Blowflies

Insects ◽

10.3390/insects11030143 ◽

2020 ◽

Vol 11 (3) ◽

pp. 143 ◽

Cited By ~ 5

Author(s):

Stefano Bedini ◽

Salvatore Guarino ◽

Maria Cristina Echeverria ◽

Guido Flamini ◽

Roberta Ascrizzi ◽

...

Keyword(s):

Antimicrobial Activity ◽

Essential Oils ◽

Foodborne Pathogens ◽

Allium Sativum ◽

Insect Pests ◽

Meat Products ◽

Rosmarinus Officinalis ◽

Salvia Officinalis ◽

Meat Processing ◽

Toxic Activity

Blowflies are known vectors of many foodborne pathogens and unintentional human ingestion of maggots by meat consumption may lead to intestinal myiasis. In fact, the control of insect pests is an important aspect of industrial and home-made food processing and blowflies (Diptera: Calliphoridae), which are among the most important pests involved in the damage of meat products. Most spices, largely used in food preparations and industry, contain essential oils that are toxic and repellent against insects and exert antimicrobial activity. In this study, we assessed the electro-antennographic responses, the oviposition deterrence, the toxicity, and the repellence of the essential oils (EOs) of Allium sativum L., Salvia officinalis L., and Rosmarinus officinalis L. against the blowfly Calliphora vomitoria L. We tested the EOs antibacterial and antifungal properties and the efficacy of an A. sativum EO-charged mist sprayed in the tunnel entryway of a meat processing room to form an olfactive barrier against the entrance of flies. The results showed that the EOs are perceived by female blowfly’ antennae and exert an evident repellent activity against them completely deterring the oviposition for up to 24 h starting from the concentration of 2.5 μL cm−2 EO. The EOs also exhibited toxic activity by both topical application (LD50 from 0.44 to 1.97 μL insect−1) and fumigation (LC50 from 1.76 to 31.52 μL L−1) against adults of C. vomitoria and were able to exert a clear antimicrobial activity toward pathogens. Lastly, the EO-charged mist was able to reduce by about 40% the presence of Calliphoridae in the meat processing room of a dry-ham factory.

Download Full-text