复配精油对粮油中霉菌防治的增效作用及机理研究

开发新型天然防霉剂控制粮食霉变是保障粮食质量安全的重要途径之一。为研究复配植物精油对粮油储藏过程中常见霉菌赭曲霉(Aspergillus ochrator)、黄曲霉(Aspergillus flavus)和黑曲霉(Aspergillus niger)的防霉效果,挑选活性较强的植物精油进行复配并对联合防霉效果进行评价。通过复配植物精油对霉菌孢子萌发、菌丝干重和细胞完整性的影响,对其防霉机理进行初步探究。结果显示,牛至精油对赭曲霉和黑曲霉的防霉效果最好,抑菌圈直径分别为（27.83±0.58 ）、（15.33±0.29）mm,肉桂醛对黄曲霉的防霉效果最好,抑菌圈直径为（18.50±0.87 ）mm;山苍子精油与牛至精油、肉桂醛与牛至精油复配体积比为2：8时对3种霉菌的防霉效果较优;通过对部分抑菌浓度指数判读,两组植物精油复配对黑曲霉和赭曲霉的防治效果为协同作用,对黄曲霉的防治效果为相加作用;山苍子精油与牛至精油按体积比2：8复配可抑制霉菌孢子萌发和菌丝生长、破坏细胞的完整性、改变孢子和菌丝结构;山苍子精油和牛至精油按体积比2：8复配施用于含黄曲霉的玉米上,可有效降低玉米中黄曲霉毒素B1和赭曲霉毒素的含量。本研究为山苍子精油与牛至精油复配作为防霉剂提供理论支持。     

Antifungal activity of Mexican oregano (Lippia berlandieri Shauer)

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.     

Antifungal Effect of Mexican Oregano (Lippia berlandieri Schauer) Essential Oil on a Wheat Flour-Based Medium

The antimicrobial activity of oregano has been attributed mainly to the presence of volatile compounds found in its essential oil (EO), mainly carvacrol and thymol. The search for antimicrobial activity of oregano EO with different concentrations of thymol and carvacrol, can lead to products with a wider range of applications. The aim of this work was to describe the in vitro antifungal effect of Mexican oregano (Lippia berlandieri Schauer) EO fractions on the growth of Aspergillus, Penicillium, and Rhizopus sp. The Mexican oregano EO fractions studied had different concentrations of carvacrol, which decreased from fraction 1 to 5 (81% to 23%), while thymol content increased from 3% to 64%. Fungal inhibition was evaluated on a wheat flour-based medium with EO fractions concentrations ranging from 50 to 200 mg/kg. Radial growth curves were fitted using the modified Gompertz model (R(2) (adj) = 0.989 ± 0.01). No significant differences (P > 0.05) were found with the different composition of the Mexican oregano EO fractions; nevertheless, fraction concentration presented significant (P < 0.05) mold inhibition as concentration increased. Rhizopus sp. (Rh18) showed a linear reduction on specific growth rate, on the maximum mold growth at the stationary phase, and an increase in the lag time as the concentration of the oregano EO increased; mold growth inhibition were achieved at 150 mg/kg in fractions 1 to 4, and at 100 mg/kg for fraction 5. Aspergillus sp. (As6) and Penicillium sp. (Pe36) were inhibited at 150 and 200 mg/kg, respectively. Results obtained suggest that Mexican oregano EO (Lippia berlandieri Schauer) compounds could be used as antimicrobial agents to prevent fungal growth in bakery products.     

Biocontrol of Salmonella Typhimurium in RTE foods with the virulent bacteriophage FO1-E2

Antimicrobial agents can be incorporated into edible films to provide microbiological stability, since films can be used as carriers of a variety of additives to extend product shelf life and reduce the risk of microbial growth on food surfaces. Addition of antimicrobial agents to edible films offers advantages such as the use of small antimicrobial concentrations and low diffusion rates. The aim of this study was to evaluate inhibition by vapor contact of Aspergillus niger and Penicillium digitatum by selected concentrations of Mexican oregano (Lippia berlandieri Schauer), cinnamon (Cinnamomum verum) or lemongrass (Cymbopogon citratus) essential oils (EOs) added to amaranth, chitosan, or starch edible films. Essential oils were characterized by gas chromatography-mass spectrometry (GC/MS) analysis. Amaranth, chitosan and starch edible films were formulated with essential oil concentrations of 0.00, 0.25, 0.50, 0.75, 1.00, 2.00, or 4.00%. Antifungal activity was evaluated by determining the mold radial growth on agar media inoculated with A. niger and P. digitatum after exposure to vapors arising from essential oils added to amaranth, chitosan or starch films using the inverted lid technique. The modified Gompertz model adequately described mold growth curves (mean coefficient of determination 0.991 ± 0.05). Chitosan films exhibited better antifungal effectiveness (inhibition of A. niger with 0.25% of Mexican oregano and cinnamon EO; inhibition of P. digitatum with 0.50% EOs) than amaranth films (2.00 and 4.00% of cinnamon and Mexican oregano EO were needed to inhibit the studied molds, respectively). For chitosan and amaranth films a significant increase (p<0.05) of lag phase was observed among film concentrations while a significant decrease (p<0.05) of maximum specific growth was determined. Chitosan edible films incorporating Mexican oregano or cinnamon essential oil could improve the quality of foods by the action of the volatile compounds on surface growth of molds.     

ANTIFUNGAL ACTIVITIES OF THYME, CLOVE AND OREGANO ESSENTIAL OILS

The antifungal potential of essential oils of oregano (Origanum vulgare), thyme (Thymus vulgaris) and clove (Syzygium aromaticum) was determined. To establish this antifungal potential, two molds related to food spoilage, Aspergillus niger and Aspergillus flavus, were selected. The agar dilution method was employed for the determination of antifungal activities. The three essential oils analyzed presented inhibitory effects on both molds tested. Oregano essential oil showed the highest inhibition of mold growth, followed by clove and thyme. Aspergillus flavus was more sensitive to thyme essential oil than A. niger. Clove essential oil was a stronger inhibitor against A. niger than against A. flavus.     

Inhibitory effects of selected Turkish spices and oregano components on some foodborne fungi

The inhibitory effects of 10 selected Turkish spices, oregano essential oil, thymol and carvacrol towards growth of 9 foodborne fungi were investigated in culture media with pH 3.5 and 5.5. The antifungal effects of sodium chloride, sorbic acid and sodium benzoate and the combined use of oregano with sodium chloride were also tested under the same conditions for comparison. Of the spices tested, only sodium chloride were also tested under the same conditions for comparison. Of the spices tested, only oregano at 1.0, 1.5, 2.0% (w/v) levels showed effect on all fungi. 8% (w/v) sodium chloride was less effective than oregano. Oregano essential oil, thymol or carvacrol at concentrations of 0.025% and 0.05% completely inhibited the growth of all fungi, showing greater inhibition than sorbic acid at the same concentrations. The combined use of oregano and sodium chloride exhibited a synergistic antifungal effect.     

Fungal Inactivation by Mexican Oregano (Lippia berlandieri Schauer) Essential Oil Added to Amaranth,Chitosan, or Starch Edible Films

ABSTRACT: Edible films can incorporate antimicrobial agents to provide microbiological stability, since they can be used as carriers of a wide number of additives that can extend product shelf life and reduce the risk of pathogenic bacteria growth on food surfaces. Addition of antimicrobial agents to edible films offers advantages such as the use of low antimicrobial concentrations and low diffusion rates. The aim of this study was to evaluate inhibition of Aspergillus niger and Penicillium spp. by selected concentrations of Mexican oregano (Lippia berlandieri Schauer) essential oil added to amaranth, chitosan, or starch edible films. Oregano essential oil was characterized by gas chromatography-mass spectrometry (GC/MS) analysis. Amaranth, chitosan, and starch edible films were formulated with essential oil concentrations of 0%, 0.25%, 0.50%, 0.75%, 1%, 2%, and 4%. Mold radial growth was evaluated inoculating spores in 2 ways: edible films were placed over inoculated agar, Film/Inoculum mode (F/I), or the edible films were first placed in the agar and then films were inoculated, Inoculum/Film mode (I/F). The modified Gompertz model adequately described growth curves. There was no significant difference (P > 0.05) in growth parameters between the 2 modes of inoculation. Antifungal effectiveness of edible films was starch > chitosan > amaranth. In starch edible films, both studied molds were inhibited with 0.50% of essential oil. Edible films added with Mexican oregano essential oil could improve the quality of foods by controlling surface growth of molds.     

Control of Aspergillus flavus with essential oil and methanol extract of Satureja hortensis

The essential oil and methanol extract of Satureja hortensis were tested for antifungal activity against Aspergillus flavus in vitro on Petri plates and liquid culture, and under storage conditions. The oil showed strong antifungal activity based on the inhibition zone and minimal inhibitory concentration values against the pathogen on Petri plates assays. The very low concentrations of them also reduced wet and dry mycelium weight of pathogen fungus in liquid culture. When the oils at 25, 12.5 and 6.25 microl/mL concentrations were applied to lemon fruits before seven days of pathogen inoculation on storage conditions, the decay on fruits caused by the pathogen could be prevented completely. The results in this study showed that the essential oil of S. hortensis had strong antifungal activity against pathogen fungi tested. So, the essential oil of S. hortensis could be used for management of this pathogen as a potential source of sustainable eco-friendly botanical fungicides.     

Chemical stability of extra-virgin olive oil added with oregano essential oil

Extra virgin olive oil is highly consumed and well known for its nutritional and health benefits. However, it is fatty food highly susceptible to lipid oxidation. The objective of this study was to evaluate the preserving effect of oregano (Origanum vulgare L. spp vulgare called "oregano compacto") essential oil on physical and chemical properties in extra virgin olive oil during storage. Oregano essential oil composition was analyzed by GC-MS. This essential oil was added into extra virgin olive oil at 0.05%. The samples were stored in 3 different conditions: darkness, light exposure, and temperature (60 °C). Chemical indicators of lipid oxidation (peroxide value, p-anisidine value, conjugated dienes, free fatty acidity, and carotenoid and chlorophyll contents) were measured. High content in carvomenthol (22.52%), terpinolene (19.77%), thymol (13.51%), and γ-terpinene (10.30%) were detected in oregano essential oil. Olive oil samples without oregano essential oil stored at 60 °C and exposure at artificial light had the highest peroxide values during storage. Higher p-anisidine and K232 values after day 7 of storage were detected in temperature, darkness, and light exposure treatments. Light treatment was the main factor that degraded chlorophyll causing loss of color. The highest chlorophyll content (3.87 mg/kg) was observed in olive oil with essential oil at the end of storage. In general, olive oil samples added with oregano essential oil had lower peroxide, conjugated dienes, and p-anisidine values and higher chlorophyll and carotenoid contents during storage. Oregano essential oil retards lipid oxidation process in olive oil prolonging its shelf life. PRACTICAL APPLICATION: Oregano essential oil was and is used with the purpose of flavoring and aromatizing food. This essential oil due to its composition has shown antioxidant activity. Synthetic antioxidants such as butylated hydroxytoluene (BHT) and butylated hydroxyanisole (BHA) are thought to be promoters of carcinogenesis. Extra virgin olive oil is widely consumed because of its nutritional benefits and sensory properties which are very important to be preserved in the product. In this study, the oregano essential oil showed remarkable antioxidant activity in olive oil. Therefore, this essential oil could be considered for the industry as natural antioxidant not only to be used in olive oil but also in other fatty food products to substitute synthetic ones.     

Evaluation of Different Mexican Plant Extracts to Control Anthracnose

The fungal plant infection caused by Colletotrichum gloeosporioides known as anthracnose, affects tropical fruits thus causing low yield and poor fruit quality. The antifungal activity of ethanol and chloroform extracts of different Mexican plants jarilla (Baccharis salicifolia), tepozan (Buddleia americana), nanche (Byrsonima cordata), cinco negritos (Lantana camara), Mexican oregano (Lippia berlandieri var. Scanner), and pericon (Tagetes lucida) against C. gloeosporioides were evaluated by determining the minimum inhibitory concentration (MIC) of the ethanol and chloroform extracts. Subsequently, an antifungal assay was carried out by determining the inhibition of radial growth in PDA plates added with plant extracts. Jarilla, oregano, and pericon MIC values were 400 mg/L for ethanol extracts and 200 mg/L for chloroform extracts. Tepozan, nanche, and cinco negritos showed no antifungal effect. Concerning the inhibition of radial growth, pericon ethanol extract showed an 84% inhibition; chloroform extracts of jarilla, oregano, and pericon showed 88%, 90%, and 95% inhibition, respectively. The ethanol extracts of oregano and jarilla demonstrated to be inhibitory at the reproductive phase of C. gloeosporioides, while their chloroform extracts have a fungistatic effect.     

山苍子精油抑制黄曲霉菌的生长和产毒作用研究

山苍子精油是一种纯天然植物精油,本文研究了其对黄曲霉生长、代谢和毒素产生的抑制作用,探讨了山苍子精油对黄曲霉菌的抑菌能力和作用机理。本研究将花生放置于自然环境染菌并分离纯化目标菌,采用形态学并结合ITS序列法进行菌株分类鉴定;结合抑菌圈、抑菌率和最低抑菌浓度(MIC)的测定探讨山苍子精油对黄曲霉菌的抑制能力;进行了山苍子精油影响黄曲霉孢子萌发率、生长曲线和黄曲霉毒素B1产生的实验研究;从细胞膜渗透性、细胞酶活性的变化探讨了山苍子精油抑制黄曲霉的作用机理。实验结果表明:从腐败花生中分离筛选出菌株HB₂,经ITS序列法鉴定为黄曲霉(Aspergillus flavus);黄曲霉素测定结果显示其含有黄曲霉素B1(AFB1),质量浓度为3.4×10³μg·kg^-1(纯湿菌体);抑菌圈随精油浓度的增大明显变大,对黄曲霉的最低抑菌体积分数(MIC)为0.800μL·mL^-1;孢子萌发率、牙管长度、黄曲霉菌体的生长量和AFB1的浓度随培养液中精油浓度的增大呈显著下降趋势,当山苍子精油浓度为0.100μL·mL     

壳聚糖涂膜与牛至精油复配对鲜切菠萝的 保鲜作用

目的研究壳聚糖涂膜及与牛至精油复配对鲜切菠萝的保鲜的影响。方法在低温环境中,按照0.1%、0.3%和0.5%不同浓度的牛至精油与壳聚糖复配,并分别以水、壳聚糖涂膜处理为对照,分析不同处理方式对鲜切菠萝硬度、Vc含量、过氧化物酶(POD)、多酚氧化酶(PPO)、过氧化氢酶(CAT)和脂氧合酶(LOX)活性的影响。结果壳聚糖涂膜与0.5%的牛至精油复配后可减缓组织软化;与0.1%牛至精油复配可以维持Vc含量的缓慢降低。在不同处理组中,当含有0.3%和0.5%牛至精油时,鲜切菠萝的POD和CAT活性则呈下降趋势,而其他处理组则显著升高;当含有壳聚糖处理组时,其PPO和LOX活性则低于对照组。结论壳聚糖与牛至精油复配涂膜会在减缓鲜切菠萝营养损失的情况下延长其货架期。     

牛至精油结合不同包装方式对冷鲜羊肉保鲜效果的影响

该文探讨植物精油和包装方式对冷鲜羊肉货架期及其品质的影响。研究采用2×2双因子试验设计,利用牛至精油和不同包装方式结合的保鲜方法研究羊肉在4℃下贮藏0、3、6、9、12 d的质构特性、肉色、pH、过氧化值(peroxide value,POV)、丙二醛(malondialdehyde,MDA)、挥发性盐基氮(total volatile base-nitrogen,TVB-N)及菌落总数(total bacteria count,TBC)的变化。结果表明,冷鲜羊肉贮存至第12天时,牛至精油与真空包装结合组中肉的红度(a^*值)、硬度、弹性、回复性均极显著高于牛至精油和普通包装结合组(P <0. 01),且其黏附性、POV、MDA、TVB-N和TBC在第12天时均极显著低于牛至精油和普通包装结合组中冷鲜羊肉该指标(P <0. 01)。牛至精油与真空包装结合的保鲜方法可使冷鲜羊肉贮藏时间延长至12 d。     

Extracts of Mexican Oregano (<Emphasis Type="Italic">Lippia berlandieri</Emphasis> Schauer) with Antioxidant and Antimicrobial Activity

Antimicrobial activity of fractions obtained from Mexican oregano (Lippia berlandieri Schauer) chloroform extract was tested by growth inhibition against Escherichia coli, Staphylococcus aureus and Bacillus cereus, and antioxidant capacity was tested by inhibition of linoleic acid oxidation. Fractions were obtained by differences in polarity or structure (phenolic and non-phenolic fraction). Gram-positive organisms were more susceptible to Mexican oregano extracts. Fraction 3 (by polarity) and phenolic fractions I, II, III, IV and V were the extracts with higher antimicrobial activity. The non-phenolic fraction had effect against B. cereus. Polarity fraction 5 and phenolic Fraction II had a high antioxidant capacity; a 0.08% concentration of fraction 5 had a similar effect as butylated hydroxytoluene at 0.01% concentration. Fractions of Mexican oregano with different polarity and functional groups had antioxidant and antimicrobial activity and can be used in a variety of applications.     

牛至精油微胶囊的制备、表征及在杏贮藏期的抑菌效果

为进一步开发植物精油在果蔬采后抑菌保鲜中的应用,本实验以牛至精油为芯材,以明胶、阿拉伯胶为壁材,采用复凝聚法,通过工艺优化制备了牛至精油微胶囊,并通过扫描电子显微镜、傅里叶变换红外光谱、热重分析和差示扫描量热分析进一步表征了其理化特性和缓释性能,最后评估了不同施用剂量的牛至精油微胶囊在杏果实采后贮藏中的抑菌效果及其对腐烂率和抗病相关酶活力的影响。结果表明：牛至精油微胶囊制备最优工艺条件为芯材和壁材质量比1∶1、壁材质量比（明胶、阿拉伯胶质量比）1∶1、反应温度45 ℃、反应时间30 min,在此工艺条件下制备的牛至精油微胶囊包埋率为83.65%,载油率为74.36%,平均粒径为147 μm;与单一牛至精油（纯度为98%）相比,牛至精油微胶囊具有更好的球形和规则表面结构,保持了更高的热稳定性,并具备了缓释特性;其中,4%（以果实质量计）的牛至精油微胶囊处理降低了杏果实在贮藏期间的菌落总数、霉菌总数和腐烂率,并提高了杏果实贮藏期间过氧化物酶、L-苯丙氨酸氨解酶、β-1,3-葡聚糖酶、过氧化氢酶和几丁质酶活性,降低了杏果实贮藏期内的多酚氧化酶活性。该结果为开发基于植物精油的缓释抑菌剂提供了新思路。     

Efficacy of extract and essential oil of Lantana indica Roxb. against food contaminating moulds and aflatoxin B1 production

The study investigates the antifungal and antiaflatoxigenic efficacy of Lantana indica against Aspergillus flavus , a key storage fungus. The leaf essential oil of L. indica was found more active than leaf extracts. The oil absolutely inhibited the growth of A. flavus at 1.5 mg mL⁻¹ while ethanolic and chloroform extracts of leaf show MIC at 7.5 and 10.0 mg mL⁻¹ concentrations respectively. The oil also showed pronounced antiaflatoxigenic efficacy and completely inhibited the aflatoxin B₁ production at 0.75 mg mL⁻¹. The ethanolic and chloroformic extracts inhibited the aflatoxin B₁ production at 5.0 and 7.5 mg mL⁻¹, respectively while other extracts exhibited poor efficacy. The L. indica essential oil exhibited broad fungitoxic spectrum against twelve different storage moulds. The present findings may recommend the L. indica essential oil and its bioactive leaf extracts as natural preservative would of immense significance in view of the environmental and toxicological implications by indiscriminate use of synthetic pesticides .     

Antimicrobial Wine Formulations Active Against the Foodborne Pathogens Escherichia coli O157: H7 and Salmonella enterica

ABSTRACT:  We developed wine formulations containing plant essential oils and oil compounds effective against foodborne pathogenic bacteria Escherichia coli O157:H7 and Salmonella enterica. HPLC was used to determine maximum solubility of antimicrobials in wines as well as amounts of antimicrobials extracted by wines from commercial oregano and thyme leaves. Activity of essential oils (cinnamon, lemongrass, oregano, and thyme) and oil compounds (carvacrol, cinnamaldehyde, citral, and thymol) in wines were evaluated in terms of the percentage of the sample that resulted in a 50% decrease in the number of bacteria (BA₅₀). The ranges of activities in wines (30 min BA₅₀ values) against S. enterica/E. coli were carvacrol, 0.0059 to 0.010/0.011 to 0.021; oregano oils, 0.0079 to 0.014/0.022 to 0.031; cinnamaldehyde, 0.030 to 0.051/0.098 to 0.13; citral, 0.033 to 0.038/0.060 to 0.070; lemongrass oil, 0.053 to 0.066/0.059 to 0.071; cinnamon oil 0.038 to 0.057/0.066 to 0.098; thymol, 0.0086 to 0.010/0.016 to 0.022; and thyme oil, 0.0097 to 0.011/0.033 to 0.039. Detailed studies with carvacrol, the main component of oregano oil, showed that antibacterial activity was greater against S. enterica than against E. coli and that wine formulations exhibited high activities at low concentrations of added antimicrobials. The results suggest that wines containing essential oils/oil compounds, added or extracted from oregano or thyme leaves, could be used to reduce pathogens in food and other environments.     

Analysis of the essential oil of Mexican oregano (Lippia graveolens HBK)

The composition of the volatile oil of Mexican oregano (Lippia graveolens HBK) isolated by steam distillation was investigated by means of column chromatography, gas chromatography and mass spectrometry. A total of 33 components were identified including 22 hydrocarbons, 4 alcohols, 4 ethers, 2 phenols and 1 ketone. Of the 33 components observed in the present study 7 were identified in Mexican oregano for the first time.     

Impedance measurements to study the antimicrobial activity of essential oils from Lamiaceae and Compositae

A wide range of essential oils from sage, mint, hyssop, camomile and oregano were tested for their inhibitory effects against nine strains of gram-negative bacteria and six strains of gram-positive bacteria. Three principles were used in describing the antimicrobial effects of the essential oils: the overall antimicrobial activity determined by use of an impedometric method, the bactericidal effect determined as colony forming units after exposure to the essential oils, and the number of apparent dead cells determined after further enrichment. The data obtained indicate that while the essential oils of sage, mint, hyssop and camomile had generally a bacteriostatic activity, the essential oil from oregano appeared to be bactericidal at concentrations above 400 ppm, probably because of high contents in phenolic compounds. For the other essential oils, the chemical analysis was unable to explain the antimicrobial effect. The bacteriostatic activity was more marked against gram-positive bacteria; in contrast, the bactericidal activity was greatest against gram-negative bacteria. The most sensitive strain was Escherichia coli O157:H7 and, of the gram-positive species even at the lowest oil concentrations, Listeria innocua was the most sensitive. The data obtained from the study of the bactericidal effect of oregano essential oil indicated that the major part of the species was irreversibly inactivated, i.e. they could not be revived by enrichment.     

The effects of dietary oregano oil supplementation on pig meat characteristics

The effects of different concentrations of dietary oregano essential oil supplementation on finishing pig meat characteristics were investigated in the present study. Thirty-two barrows and thirty-two gilts were divided into four equal groups. During the experimental period, which started when the animals were 5 months old and finished after 35 days, the first group was fed the control diet (group C), whereas the other three groups consumed the same diet, with the only difference that the feed was supplemented with oregano essential oil at concentrations of 0.25, 0.5 and 1 ml/kg of fed diet (groups OR1, OR2 and OR3, respectively). At the end of the experiment, pigs were fasted for 12 h, weighed and slaughtered. After overnight chilling, a 50 cm loin section was removed from the half of the carcasses (8 pigs per nutritional treatment; 4 barrows and 4 gilts) and transported to laboratory for further examination.