Potential of wild oregano essential oil in control of Monilinia rot on stored sweet cherry fruits

Sweet cherry fruits are perishable goods, and the fruit quality can additionally be affected by fungal diseases, primarily by Monilinia species. A promising method for fungal disease control in storage is the use of essential oils. Three different methods of wild oregano essential oil application were tested: incorporation (5% dilution), exposing to the vapor phase (0.08 and 0.16 µl/cm3), and fruit immersion in 5% dilution. Incorporation of essential oil showed the strongest inhibitory effect on Monilinia laxa in both tested cultivars (Regina and Karina). The vapor phase had the same effect on inhibition of Monilinia laxa at both concentrations on cold-stored fruits of cv. Regina after incubation at room temperature, while on cv. Karina, higher concentration showed a stronger inhibitory effect. The immersion in EO dilution caused phytotoxic changes on the fruit skin. Necrosis development rates significantly increased after the cold storage period terminated.

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Combined Effect of Chitosan-Based Edible Film Containing Oregano Essential Oil on the Shelf-Life Extension of Fresh Chicken Meat

Journal of Nutrition and Food Security ◽

10.18502/jnfs.v4i4.1720 ◽

2019 ◽

Author(s):

Fatemeh Karimnezhad ◽

Vadood Razavilar ◽

AmirAli Anvar ◽

Shahrzad Dashtgol ◽

Atefeh Pilehvar Zavareh

Keyword(s):

Essential Oil ◽

Shelf Life ◽

Storage Period ◽

Inhibitory Effect ◽

Edible Film ◽

Life Extension ◽

Control Group ◽

Oregano Essential Oil ◽

Water Distillation ◽

Oregano Oil

Background: The aim of this study was to investigate the effects of chitosan coatings, oregano essential oil, and their combination on microbial quality of chicken fillet during 12 days in refrigerator temperature. Methods: Oregano oil was extracted by water distillation and then different concentrations of oregano oil (1% and 2%) were used for film preparation. Microbiological tests were carried out on the chicken fillet samples stored in 4 °C at different intervals including days 0, 3, 6, 9, and 12. Results: Treated groups with chitosan and oregano oil affected the increase rate of aerobic plate counts, coliform counts, and total psychrophilic counts significantly compared to the control group across the entire storage period (P < 0.05). Chitosan-based edible film containing oregano oil inhibited microbial growth on chicken fillet. Microbial populations were reduced by 2.14-3.53 log CFU/g in groups treated with chitosan and oregano oil. Our results revealed that incorporation of oregano essential oil at 2% concentration had the highest inhibitory effect on spoilage microorganisms in coated chicken fillet during 12 days of storage at refrigerator. Conclusion: Generally, application of oregano essential oil at 2% concentration had the potential to enhance safety and shelf-life of chicken fillet.

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INHIBICIÓN DEL CRECIMIENTO DE Salmonella spp y Staphylococcus aureus POR EFECTO DEL ACEITE ESENCIAL DE ORÉGANO EN UNA PELÍCULA BIODEGRADABLE ACTIVA DE ÁCIDO POLILÁCTICO

Revista Bases de la Ciencia. e-ISSN 2588-0764 ◽

10.33936/rev_bas_de_la_ciencia.v5i1.2035 ◽

2020 ◽

Vol 5 (1) ◽

pp. 41

Author(s):

Anderson Javier Pazmiño Castro ◽

Ana María Campuzano Vera ◽

Karina Marisabel Marín Morocho

Keyword(s):

Staphylococcus Aureus ◽

Essential Oil ◽

Microbial Control ◽

Antibacterial Properties ◽

Inhibitory Effect ◽

Biodegradable Films ◽

Origanum Vulgare ◽

Salmonella Spp ◽

Produce Cell ◽

Oregano Essential Oil

Con la finalidad de reducir el número de personas afectadas por enfermedades transmitidas por alimentos,se elaboraron películas biodegradables activas con propiedades antibacterianas a partir de ácido poliláctico, polietilenglicol, y aceite esencial de orégano (Origanum vulgare) al 1% (p/p) y 2 % (p/p). Las películas biodegradables activas fueron elaboradas mediante el método de evaporación del solvente. Se evaluó la acción antibacteriana de las películas biodegradables activas mediante un ensayo de inhibición a la adhesión microbiana contra Salmonella spp. y Staphylococcus aureus. Se pudo establecer que los porcentajes de aceite esencial aplicados tienen poco efecto inhibitorio sobre Staphylococcus aureus, mientras que para Salmonella spp. hay un efecto directo sobre la inhibición, cuando la concentración de aceite esencial es del 2% (p/p). Para una concentración del 1% (p/p), el efecto inhibidor observado fue pobre. Los resultados indican que las bacterias Gram-negativas Salmonella spp son más susceptibles al daño en la pared celular provocado por el aceite esencial de orégano, debido al menor espesor de la misma. En contraste, el mayor grosor de la pared celular que presentan las bacterias Gram-positivas Staphylococcus aureus exige, en principio, de un tiempo mayor para poder producir la lisis celular. Las películas biodegradables activas con aceite esencial de orégano pueden emplearse para la conservación de los alimentos como una tecnología de barrera en conjunto con otros mecanismos de control microbiano y así minimizar tratamientos térmicos severos o reducir la utilización de aditivos alimentarios, que en concentraciones inadecuadas pueden producir cierta toxicidad. Palabras clave: películas biodegradables activas, contaminación de alimentos, inhibición bacteriana. Abstract In order to reduce the number of people affected by foodborne illnesses, active biodegradable films with antibacterial properties were made with polylactic acid, polyethylene glycol, and essential oil of oregano (Origanum vulgare) at 1% (w/w) and 2% (w/w). The active biodegradable films were made using solvent evaporation method. The active biodegradable films antibacterial action was evaluated by microbial adhesion inhibition test against Salmonella spp. and Staphylococcus aureus. It was established that the percentages of essential oil used have little inhibitory effect on Staphylococcus aureus, while for Salmonella spp. there is a direct effect on inhibition, when the essential oil concentration is 2% (w/w). For a concentration of 1% (w/w), the observed inhibitory effect was poor. The results indicate that Gram-negative bacterias Salmonella spp are more susceptible to cellular wall damage caused by oregano essential oil, due to its lower thickness. In contrast, the greater thickness of the cell wall that Staphylococcus aureus, Gram-positive bacteria has, requires, in principle, a longer time to produce cell lysis. Biodegradable active films with oregano essential oil can be used for food preservation as a barrier technology in conjunction with other microbial control mechanisms, thus minimizing severe heat treatments or reducing the use of food additives that, in inadequate concentrations can produce some toxicity. Keywords: active biodegradable films, food pathogens, bacterial inhibition.

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Response of Aspergillus niger Inoculated on Tomatoes Exposed to Vapor Phase Mustard Essential Oil for Short or Long Periods and Sensory Evaluation of Treated Tomatoes

Journal of Food Quality ◽

10.1155/2017/4067856 ◽

2017 ◽

Vol 2017 ◽

pp. 1-7 ◽

Cited By ~ 2

Author(s):

Ana Elena Aguilar-González ◽

Enrique Palou ◽

Aurelio López-Malo

Keyword(s):

Aspergillus Niger ◽

Essential Oil ◽

Sensory Evaluation ◽

Vapor Phase ◽

Petri Dish ◽

Good Alternative ◽

Inhibitory Effect ◽

Mustard Essential Oil

The inhibitory effect of mustard essential oil (EO) in vapor phase against Aspergillus niger was evaluated in vitro and in vivo (in tomatoes). Mold response in tomatoes exposed for short or long periods to selected concentrations of mustard EO was also evaluated. Furthermore, a sensory evaluation was also performed among treated tomatoes and compared with nontreated ones. Minimum inhibitory concentration (MIC) for the studied EO was determined by the inverted Petri dish method. MIC for the in vitro and in vivo tests for mustard EO was of 3.08 μL/Lair. In vitro and in vivo results demonstrate the effectiveness of vapors of mustard EO against A. niger. The studied EO contains highly volatile organic compounds with strong inhibitory effects, even when applied for short periods, and can consequently be considered a good alternative to traditional synthetic antimicrobials without detriment of selected sensory attributes.

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Antifungal Activity of Oregano and Thyme Essential Oils Applied as Fumigants Against Fungi Attacking Stored Grain

Journal of Food Protection ◽

10.4315/0362-028x-58.1.81 ◽

1995 ◽

Vol 58 (1) ◽

pp. 81-85 ◽

Cited By ~ 153

Author(s):

NACHMAN PASTER ◽

MAZAL MENASHEROV ◽

UZI RAVID ◽

BENJAMIN JUVEN

Keyword(s):

Essential Oil ◽

Essential Oils ◽

Fungicidal Activity ◽

Inhibitory Effect ◽

Aspergillus Ochraceus ◽

Stored Grain ◽

Oregano Essential Oil ◽

Thyme Essential Oil ◽

Natural Microflora ◽

Oregano Oil

Essential oils from oregano and thyme were applied for 24 h as fumigants against the mycelia and spores ofAspergillus flavus, Aspergillus niger and Aspergillus ochraceus, as well as against natural microflora of wheat grains. The minimal inhibitory concentration (MIC) of oregano oil needed to inhibit the mycelial growth of the fungi was 2.0 μl/L, while spores were eradicated following exposure to 2.0 to 2.5 μl/L. The thyme essential oil was less efficient in controlling mycelia and growth was observed even following exposure to 4.0 μl/L. However, the thyme essential oil was fungitoxic to spores (MIC = 3.0 μl/L). In another set of trials the efficacy of the oils and two of their constituents (carvacrol and thymol) in controlling natural microflora of surface-sterilized wheat grain was studied. Of the four materials investigated, only oregano essential oil exhibited fungicidal activity and, following 24 h exposure to 20 μl/L, a significant reduction in the percent of infested grain was observed even after 5 days of incubation on potato dextrose agar. A reduction in the germinability of the grains was evident following exposure to the materials tested. When the fungicidal activity of oregano essential oil was evaluated using grains with different moisture contents (MC), data revealed that the better inhibitory effect was achieved in grain with a high MC. The findings emphasize the toxicity of oregano and thyme essential oils as fumigants against fungi attacking stored grain and strengthen the possibility of using them as an alternative to chemicals for preserving stored grains.

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Application of Gelatin Composite Coating in Pork Quality Preservation during Storage and Mechanism of Gelatin Composite Coating on Pork Flavor

Gels ◽

10.3390/gels8010021 ◽

2021 ◽

Vol 8 (1) ◽

pp. 21

Author(s):

Haoxin Li ◽

Renrun Tang ◽

Wan Aida Wan Mustapha ◽

Jia Liu ◽

K. M. Faridul Hasan ◽

...

Keyword(s):

Weight Loss ◽

Essential Oil ◽

Composite Coating ◽

Room Temperature ◽

Meat Products ◽

Storage Period ◽

Control Group ◽

Fish Gelatin ◽

Gelatin Coating ◽

Color Texture

Gelatin coating is an effective way to prolong the shelf life of meat products. Aiming at solving the problem of flavor deterioration during the storage of pork at room temperature, pork coating technology was developed to preserve the pork at 25 °C, and the comprehensive sensory analysis of vision, touch, smell, and taste was used to study the effect of coating on preservation of pork flavor. Herein, uncoated (control) and coated pork samples (including gelatin coating and gelatin coating incorporated with ginger essential oil) were analyzed to investigate the integrity of pork periodically during storage at 25 °C for weight loss, color, texture (springiness, chewiness, cohesiveness, gumminess, and hardness), microstructure, odor (electronic nose), taste (electronic tongue), volatile flavor substance, and taste ingredients. The results suggested that ginger essential oil (GEO) gelatin coating and gelatin coating can effectively inhibit the loss of water dispersion and slow down the oxidation reaction, coating treatments could significantly (p < 0.05) retarded the weight loss of pork slices, with values of 20.19%, 15.95%, 13.12% for uncoated, gelatin coated, and GEO-gelatin coated samples during 24 h of storage, respectively. Compared with control group, the color, texture, smell, and taste evaluations demonstrated that coating treatments had improved sensory and texture attributes during the storage period. Furthermore, the comprehensive results from the physical property assays (especially the texture), morphological assay and volatile odor assays showed that the GEO-fish gelatin composite coating had better preservation effect on pork flavor than the fish gelatin coating. The study suggests that the gelatin composite coating could be developed as a prospective active packaging to preserve pork meat at room temperature.

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Antifungal Activity of Mexican Oregano (Lippia berlandieri Shauer)

Journal of Food Protection ◽

10.4315/0362-028x-68.12.2713 ◽

2005 ◽

Vol 68 (12) ◽

pp. 2713-2717 ◽

Cited By ~ 19

Author(s):

MARTHA CRISTINA PORTILLO-RUIZ ◽

SABINA VIRAMONTES-RAMOS ◽

LAILA NAYZZEL MUÑOZ-CASTELLANOS ◽

MARÍA GUADALUPE GASTÉLUM-FRANCO ◽

GUADALUPE VIRGINIA NEVÁREZ-MOORILLÓN

Keyword(s):

Antifungal Activity ◽

Essential Oil ◽

Morphological Characteristics ◽

Pathogenic Fungi ◽

Inhibitory Effect ◽

Food Preservation ◽

Well Test ◽

Oregano Essential Oil ◽

Fungal Strains ◽

Growth Measurement

Antifungal and sensorial properties of spices have been recognized for years. The antifungal compounds are products of the plant's secondary metabolism, and the action of those compounds could be used to inhibit the growth of spoilage and pathogenic microorganisms in food. Mexican oregano (Lippia berlandieri) grows wildly in the desert zone of Mexico and is usually added to regional foods. The goal of this study was to evaluate the antifungal activity of Mexican oregano versus food-contaminant fungi. Fungi were isolated from spoiled fruit and vegetables and identified according to morphological characteristics. The antifungal activity of oregano was evaluated by radial growth measurement on potato dextrose agar added with dried oregano (0.25 to 4.0%). The essential oil antifungal activity of oregano was also evaluated by the diffusion well test. Twenty-one fungal strains were isolated, which included Penicillium, Geotrichum, Aspergillus, and Bipolaris. In seven of the 21 strains, no inhibitory effect was observed at either concentration of oregano. An increase in growth at the lower or higher concentrations of oregano, when compared to the control, was observed in two fungal strains; in 12 strains, a strong inhibitory effect of oregano was evident. The oregano essential oil was inhibitory to all fungal strains, but there were differences in the extent of the effect. Although the antifungal effect of oregano is strongly established, there was a differential effect with the fungal strains studied. Besides pathogenic fungi and bacteria, microbial spoilage flora should be considered when the addition of spices for food preservation is proposed.

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CARACTERIZACIÓN QUÍMICA DEL ACEITE ESENCIAL DE ORÉGANO COMO AGENTE BIOCONSERVADOR EN ALIMENTOS

Universidad Ciencia y Tecnología ◽

10.47460/uct.v24i105.381 ◽

2020 ◽

Vol 24 (105) ◽

pp. 54-62

Author(s):

César Mera Mendoza

Keyword(s):

Essential Oil ◽

Essential Oils ◽

Antibacterial Properties ◽

Antimicrobial Effect ◽

Inhibitory Effect ◽

Edible Films ◽

Methyl Silicone ◽

Ultrasound Assisted Extraction ◽

Oregano Essential Oil ◽

Spoilage Bacteria

Se ha analizado químicamente el aceite esencial de orégano cultivado en el cantón El Empalme en Ecuador para aplicarlo como agente bioconservador en alimentos. Para ello se empleó cromatografía de gases acoplada con espectrometría de masas. Se identificó como componente principal el carvacrol con 62,41%, seguido de β-cariofileno 8,84%, α-bergamoteno 6,75%, p-cimeno 6,24%, geraniol 4,29%; y α-humuleno, β-felandreno, 1-octen-3-ol, oxido de cariofileno, 4-terpineol, E-citral, γ-terpineno, z-citral en pequeñas cantidades. El Carvacrol le otorga al orégano múltiples propiedades antioxidantes, microbiológicas y conservantes de alimentos, además de potenciales aplicaciones en perfumería y cosmética. Palabras Clave: Orégano, aceite esencial, cromatografía de gases, espectrometría de masas. Referencias [1]J. Bruneton, Farmacognosia. Fitoquímica, Plantas Medicinales, Zaragoza: Acribia, 2001. [2]N. Rodríguez, « Uso de agentes antimicrobianos naturales en la consevacion de frutas y hortalizas,» Ra Ximhai, vol. VII, pp. 153-170, 2011. [3]S. Burt, «Essential oils: their antibacterial properties and potential applications in foods.,» Int J Food Microbiol, pp. 223-253, 2004. [4]J. Gutiérrez, G. Rodríguez, C. Barry-Ryan y P. Bourke, «Efficacy of plant essential oils against foodborne pathogens and spoilage bacteria associated whit ready-to-eat- vegetables: Antimicrobial and sensory screening.,» Journal of Food Protection, pp. 1846-1854, 2008. [5]R. Hulankova, G. Borilova y I. Steinhauserova, «Combined antimicrobial effect of oregano essential oil and caprylic acid in minced beef.,» Meat Science, pp. 190-194, 2013. [6]I. Fernández-Pan, M. Mendoza y J. Mate, «Whey protein isolate edible films essential oils incorporated to improve the microbial quality of poultry.,» Sci Food Agric, pp. 2986-2994, 2013. [7]L. Iturriaga, I. Olabarrieta y I. Maranon, «Antimicrobial assays of natural extracts and their inhibitory effect against Listeria innocua and fish spoilage bacteria, after incorporation into biopolymer edible films.,» Int J Food Microbiol, pp. 58-64, 2012. [8]C. Mera, V. Guerrón, S. Sánchez, J. Neira y R. Moreno, «Efecto del aceite esencial de orégano (Oreganum Vulgare L.) como agente antimicrobiano en la conservación de carne de dos especies de tilapia.,» Nutrición Clínica, Dietética y Hospitalaria, nº 39, pp. 35-36, 2019. [9]J. Soriano, Micotoxinas en alimentos, Ediciones Díaz de Santos: Madrid, 2007. [10]M. Pascual, K. Slowing, E. Carretero, M. Sánchez y A. Villar, « Lippia: Traditional uses, chemistry and pharmacology.,» Ethnopharmacol, pp. 201-214, 2001. [11]H. Peredo, E. Palou y A. López, «Aceites esenciales: métodos de extracción,» Temas selectos de ingeniería de alimentos, vol. 1, nº 3, pp. 24-32, 2009. [12]A. Kimbaris y N. D. D. Siatis, «Comparison of distillation and ultrasound - assisted extraction methods for the isolation of sensitive aroma compounds from garlic,» Ultrasonics Sonochemistry, vol. 13, pp. 54-60, 2006. [13]B. Bayramoglu, S. Shamin y G. Sumnu, «Solvent-free microwave extraction of essential oil from oregano,» Journal of food engineering, nº 88, pp. 535-540, 2008. [14]M. Golmakani y K. Rezaei, «Comparison of microwave-assisted hydrodistillation with the traditional hydrodistillation method in the extraction of essential oil from Thymus Vulgarus,» Food Chemistry, nº 101, pp. 1558-1564, 2008. [15]M. Ortuño, Manual práctico de aceites esenciales, aromas y perfumes, España: Aiyana, 2006. [16]A. Caldas, «Optimización, Escalamiento y Diseño de una Planta Piloto de Extracción Sólido Líquido,» Universidad de Cuenca , Cuenca, 2012. [17]M. Méndez, K. Bodero y S. Alvarado, «Biosíntesis de nanopartículas de hierro (FE3O4) en la remidacion de aguas contaminadas,» Universidad, Ciencia y Tecnología, vol. 24, nº 96, pp. 35-45, 2020. [18]J. Sercik, «Detector in gas chromatography,» Journal of Chromatography Library, vol. 4, pp. 34-42, 1975. [19]E. Gimeno, «Compuestos fenólicos. Un análisis de sus beneficios para la salud,» Offarm, vol. 23, nº 6, pp. 80-84, 2004. [20]J. Bello, Ciencia bromatológica: principios generales de los alimentos, Madrid: Díaz de Santos, 2000. [21]R. Fonnegra y S. Jiménez, «Plantas medicinales aprobadas en Colombia,» Universidad de Antioquia, Medellín, 2007. [22]N. Davies, «Gas chromatographoic retention indices of monoterpenes and sesquiterpenes on methyl silicone and carbowax 20 M. phases.,» Journal of Chromatography A, pp. 1-24, 1990.

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Effects of developed thyme and oregano essential oil formulations on Monilinia laxa and Monilinia fructicola

Pesticidi i fitomedicina ◽

10.2298/pif2001049t ◽

2020 ◽

Vol 35 (1) ◽

pp. 49-56

Author(s):

Brankica Tanovic ◽

Jovana Hrustic ◽

Milica Mihajlovic ◽

Mila Grahovac ◽

Marija Stevanovic ◽

...

Keyword(s):

Essential Oil ◽

Essential Oils ◽

Antimicrobial Properties ◽

Monilinia Fructicola ◽

Monilinia Laxa ◽

Oregano Essential Oil ◽

In Vivo Experiments ◽

Apple Fruits

Essential oils have been well-known for their antimicrobial properties for a very long time. Some of them have been effectively used in human medicine for decades. Our earlier investigation revealed a great potential of thyme and oregano essential oils as crop protectants against some postharvest fruit pathogens. The effects of formulated thyme and oregano essential oils on Monilinia laxa and Monilinia fructicola were studied in vitro and in vivo. In vitro antagonistic assays were performed on solidified PDA medium using a slightly modified agar overlay technique, while in vivo experiments were conducted on inoculated apple fruits. In vitro essays showed that the developed formulations (emulsifiable concentrates - EC) significantly inhibited the mycelial growth of Monilinia spp. Experiments in vivo, performed on inoculated apple fruits, revealed that the developed formulations provided a significant level of Monilinia spp. suppression. To our knowledge, another EC formulation of oregano essential oil intended for use in Monilinia spp. control has never been developed before. The presented results are initial findings and evaluation of the activity of the developed products should therefore proceed under field conditions to determine their efficacy and activity spectrum, and to estimate economic aspects of their use.

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Effect of Adding Oregano Essential Oil, Garlic and Tomato Preparations Separately and in Combination on the Stability of Vacuum-Packed Minced Pork During Storage

Annals of Animal Science ◽

10.2478/aoas-2014-0065 ◽

2015 ◽

Vol 15 (1) ◽

pp. 221-235 ◽

Cited By ~ 2

Author(s):

Magdalena Michalczyk ◽

Ryszard Macura ◽

Joanna Banaś ◽

Iwona Tesarowicz ◽

Ireneusz Maciejaszek

Keyword(s):

Essential Oil ◽

Shelf Life ◽

Marked Effect ◽

Substantial Reduction ◽

Storage Period ◽

Pork Meat ◽

Oregano Essential Oil ◽

Freeze Dried ◽

Sds Page ◽

The Stability

AbstractThis paper investigates the effect of adding oregano essential oil (0.02% v/w), freeze-dried garlic (1%), tomato concentrate (15%) and a combination of all three (in the same concentrations) on the shelf life of minced pork meat. Vacuum-packed samples with additives and a control were stored at 6±1°C for 16 days. Sensory, microbiological and biochemical changes were analysed over the whole storage period. The beneficial effect of oregano essential oil was generally to inhibit lipid oxidation, although its effect on bacterial growth was very weak. Adding tomato concentrate, combined with other additives, slowed the rate of microbiological and sensory changes, but had a marked effect on changes in proteins (SDS-PAGE analysis) and the proportion of meat pigments. The addition of freeze-dried garlic did not cause a substantial reduction of detectable bacteria count. Adding a combination of all three additives resulted in a product with a distinctly longer shelf life.

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Effects of selected essential oils on the growth and production of ochratoxin A by Penicillium verrucosum

Archives of Industrial Hygiene and Toxicology ◽

10.2478/10004-1254-65-2014-2486 ◽

2014 ◽

Vol 65 (2) ◽

pp. 199-208 ◽

Cited By ~ 13

Author(s):

Barbara Jeršek ◽

Nataša Poklar Ulrih ◽

Mihaela Skrt ◽

Neda Gavarić ◽

Biljana Božin ◽

...

Keyword(s):

Essential Oil ◽

Essential Oils ◽

Ochratoxin A ◽

Abies Alba ◽

Inhibitory Effect ◽

Mentha Piperita ◽

Penicillium Verrucosum ◽

Foeniculum Vulgare ◽

Oregano Essential Oil ◽

Minimal Inhibitory Concentrations

AbstractEssential oils from oregano (Origanum vulgare L.), mint (Mentha piperita L.), fennel (Foeniculum vulgare Mill.), and pine (Abies alba Mill.) needles and cones, and their active substances thymol, carvacrol, menthol, and anisaldehyde were tested for antifungal activity against Penicillium verrucosum. The lowest minimal inhibitory concentrations (MICs) were achieved for essential oil of oregano, followed by carvacrol, thymol, and menthol. These antifungal components were further investigated, as the main aim of our study was to elucidate the effect of natural antifungals on ochratoxin A production. During 21 days of exposure, the growth of P. verrucosum, and subsequently the production of ochratoxin A, was fully inhibited by thymol at ½ MIC (0.0625 mg mL-1), but menthol at ¼ and ½ MIC (0.1875 and 3750 mg mL-1) showed no growth inhibition. After 21 days of incubation, the greatest inhibitory effect on ochratoxin production (inhibition was 96.9 %) was also achieved with thymol at ¼ MIC (0.0313 mg mL-1). Essential oil of oregano (¼ MIC, 0.2930 μL mL-1) and carvacrol (½ MIC, 0.1953 μL mL-1) stimulate production of ochratoxin A at 13.9 % to 28.8 %, respectively. The observed antifungal effects depended on the agent, the concentration used, and the time of interaction between the agent and P. verrucosum. Our results indicate the possibility of using oregano essential oil as a substitute for artificial preservatives in certain foods, but further research is needed.

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