Antibacterial activity of Thymus capitatus and Thymus algeriensis essential oils against four food‐borne pathogens inoculated in minced beef meat

2017 ◽  
Vol 38 (1) ◽  
Author(s):  
Asma Jayari ◽  
Nariman El Abed ◽  
Ahlem Jouini ◽  
Osama Mohammed Saed Abdul‐Wahab ◽  
Abderrazak Maaroufi ◽  
...  
2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Asma Jayari ◽  
Ahlem Jouini ◽  
Hager Boukhris ◽  
Safa Hamrouni ◽  
Chokri Damergi ◽  
...  

The antibacterial effects of essential oils (EOs) extracted from Thymus capitatus and Thymus algeriensis were assessed and evaluated against four pathogenic bacteria (Escherichia coli (ATCC 25922), Listeria monocytogenes (ATCC 19118), Staphylococcus aureus (ATCC 25923), and Salmonella typhimurium (ATCC 1402)) and one spoilage bacterium (Pseudomonas aeruginosa (ATCC 27853)). Both investigated EOs presented significant antimicrobial activities against all tested bacteria with a greater antibacterial effect of T. capitatus EO. In fact, the results indicated that the minimum inhibitory concentrations (MICs) and the minimum bactericidal concentrations (MBCs) of T. capitatus EO are in the range of 0.006–0.012% and 0.012–0.025%, respectively, while those of T. algeriensis EO ranged between 0.012 and 0.025% and 0.05%, respectively. Furthermore, the inhibitory effects of both EOs were appraised against the spoilage bacterium P. aeruginosa, inoculated in minced beef meat, at two different loads (105 and 108 CFU) mixed with different concentrations of EOs (0.01, 0.05, 1, and 3%) and stored at 4°C for 15 days. The obtained data demonstrated that the antibacterial effect of tested EOs varies significantly in regard to the levels of meat contamination and the concentrations of EOs. In fact, in the presence of 0.01 and 0.05% of oils, a decrease in bacterial growth p < 0.01 was observed; but, such an effect was more pronounced in the presence of higher concentrations of EOs (1 and 3%), regardless the level of meat contamination. Besides, at the low contamination level, both EOs exerted a rapid and a more pronounced antibacterial effect, as compared to the high contamination level. The results illustrated the efficacy of both EOs as preservatives in food against well-known pathogens of food-borne diseases and food spoilage, particularly in P. aeruginosa in beef meat. As regards sensory evaluation, the presence of T. capitatus EO proved to improve the sensory quality of minced beef meat.


2018 ◽  
Vol 16 (S1) ◽  
pp. S155-S163 ◽  
Author(s):  
S. Mehalaine ◽  
O. Belfadel ◽  
T. Menasria ◽  
A. Messaili

The present study was carried out to determine, for the first time, the chemical composition and antibacterial activity of essential oils derived from the aerial parts of three aromatic plants Thymus algeriensis Boiss & Reut, Rosmarinus officinalis L., and Salvia officinalis L. growing under semiarid conditions. The essential oils were chemically analyzed and identified by gas chromatography (GC) and GC/ mass spectrometry (GC/MS) and their antimicrobial activity was individually evaluated against Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa using both agar disk diffusion and agar dilution methods. The major constituents of Thymus algeriensis essential oil were identified as camphor (13.62%), 1,8-cineol (6.00%), borneol (5.74%), viridiflorol (4.00%), and linalool (3.93%). For Rosmarinus officinalis essential oil, 48 compounds were characterized, of which the main constituents were camphor (17.09%), Z-β-ocimene (10.88%), isoborneol (9.68%), α-bisabolol (7.89%), and borneol (5.11%). While, Salvia officinalis essential oil was characterized by β-thujone (16.44%), followed by viridiflorol (10.93%), camphor (8.99%), 1,8-cineol (8.11%), trans-caryophyllene (5.85%), and α-humulene (4.69%) as the major components. Notably, results from antibacterial screening indicated that Thymus algeriensis and Salvia officinalis essential oils exhibited a strong inhibitory effect against both Escherichia coli and Staphylococcus aureus compared to Rosmarinus officinalis essential oil. Further, less activity was recorded against Pseudomonas aeruginosa for the three tested essential oils.


Molecules ◽  
2021 ◽  
Vol 26 (8) ◽  
pp. 2124
Author(s):  
Giulia Vanti ◽  
Ekaterina-Michaela Tomou ◽  
Dejan Stojković ◽  
Ana Ćirić ◽  
Anna Rita Bilia ◽  
...  

Food poisoning is a common cause of illness and death in developing countries. Essential oils (EOs) could be effective and safe natural preservatives to prevent and control bacterial contamination of foods. However, their high sensitivity and strong flavor limit their application and biological effectiveness. The aim of this study was firstly the chemical analysis and the antimicrobial evaluation of the EOs of Origanum onites L. and Satureja thymbra L. obtained from Symi island (Greece), and, secondly, the formulation of propylene glycol-nanovesicles loaded with these EOs to improve their antimicrobial properties. The EOs were analyzed by GC-MS and their chemical contents are presented herein. Different nanovesicles were formulated with small average sizes, high homogeneity, and optimal ζ-potential. Microscopic observation confirmed their small and spherical shape. Antibacterial and antifungal activities of the formulated EOs were evaluated against food-borne pathogens and spoilage microorganisms compared to pure EOs. Propylene glycol-nanovesicles loaded with O. onites EO were found to be the most active formulation against all tested strains. Additionally, in vitro studies on the HaCaT cell line showed that nanovesicles encapsulated with EOs had no toxic effect. The present study revealed that both EOs can be used as alternative sanitizers and preservatives in the food industry, and that their formulation in nanovesicles can provide a suitable approach as food-grade delivery system.


2012 ◽  
Vol 7 (8) ◽  
pp. 1934578X1200700 ◽  
Author(s):  
Erich Schmidt ◽  
Jürgen Wanner ◽  
Martina Höferl ◽  
Leopold Jirovetz ◽  
Gerhard Buchbauer ◽  
...  

The essential oils of four chemotypes of Thymus vulgaris L. (Lamiaceae) were analyzed for their composition and antibacterial activity to assess their different properties. GC-MS and GC-FID analyses revealed that the essentials oils can be classified into the chemotypes thymol (41.0% thymol), geraniol (26.4% geraniol), linalool (72.5% linalool) and 4-thujanol/terpinen-4-ol (42.2% cis- and 7.3% trans-sabinene hydrate, 6.5 % terpinen-4-ol). The olfactory examination confirmed the explicit differences between these chemotypes. Furthermore, antibacterial activity was investigated against several strains of two Gram-positive ( Brochothrix thermosphacta and Staphylococcus aureus) and four Gram-negative food-borne bacteria ( Escherichia coli, Salmonella abony, Pseudomonas aeruginosa and P. fragi). All essential oil samples were demonstrated to be highly effective against Gram-positive strains, whereas the impact on Gramnegative microorganisms was significantly smaller, but still considerable. The results obtained indicate that, despite their different properties, the essential oils of selected T. vulgaris chemotypes are potent antimicrobials to be employed as useful additives in food products as well as for therapeutic applications.


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