Chemical composition and in vitro antibacterial activity of Mentha spicata essential oil against common foodborne pathogenic bacteria

The aim of the present study was to investigate chemical composition and antibacterial activity of essential oil from the leaf of Mentha spicata plant against common food-borne pathogenic bacteria (Staphylococcus aureus, Bacillus subtilis, Bacillus cereus, Listeria monocytogenes, Salmonella typhimurium, and Escherichia coli O157:H7). Chemical composition of the essential oil was identified by gas chromatography coupled with mass spectrometer detector (GC-MS). The antibacterial activity of the essential oil was evaluated by broth microdilution method and agar disk diffusion assay. According to the result of GC-MS analysis, 18 components were identified, accounting for 99.89% of the whole essential oil. The main components were carvone (78.76%), limonene (11.50%), -bourbonene (11.23%), cis-dihydrocarveol (1.43%), trans-caryophyllene (1.04%), menthone (1.01%), menthol (1%), and terpinen-4-ol (0.99). The essential oil exhibited moderate level of antibacterial activity against all test microorganisms. In general, Gram-positive bacteria were more susceptible to M. spicata essential oil than Gram-negative bacteria. L. monocytogenes was the most sensitive of the microorganisms to the antibacterial activity of M. spicata essential oil (inhibition zone = 22 mm and MIC and MBC = 2.5 L/mL). Based on our results, the essential oil of M. spicata plant collected from Kermanshah province, west of Iran, has a potential to be applied as antibacterial agent

Ziziphora clinopodioides

The aim of the present study was to evaluate the effects of Ziziphora clinopodioides essential oil (0.1 and 0.2%) and nisin (250 and 500 IU/mL) separately and in combination on survival of Escherichia coli O157:H7 inoculated in Doogh (Iranian yoghurt drink) during storage under refrigerated temperature (4 ± 1°C) for 9 days. Viability of Lactobacillus casei at different concentrations of Z. clinopodioides essential oil (0.1 and 0.2%) in Doogh was also examined. The major components were carvacrol (64.22%), thymol (19.22%), γ-terpinene (4.63%), and p-cymene (4.86%). There was no significant difference (p>0.05) between samples treated with nisin and those of untreated samples. Samples treated with both concentrations of the essential oil (0.1 and 0.2%) showed populations of E. coli O157:H7 significantly (p<0.05) lower than those of untreated samples. The essential oil of Z. clinopodioides in combination with nisin had a potential synergistic effect against E. coli O157:H7 in Doogh samples after 5 days. The count of L. casei was not inhibited by different concentrations of the Z. clinopodioides essential oil. It is concluded that the leaf essential oil of Z. clinopodioides in combination with nisin can be applied as alternative antimicrobial agents in Doogh to inhibit the growth of E. coli O157:H7

Effects of Oregano Extract on the Inhibition of Selected Pathogens in Raw Beef Meat

Introduction: Listeria monocytogenes, Salmonella spp. and Staphylococcus aureus have been found in raw meat and meat products. The present study aimed to evaluate the effects of oregano extract(OE) at the concentrations of 0.1%, 0.2%, and 0.5%against Listeria monocytogenes, Salmonella typhimurium, and Staphylococcus aureus in raw beef meat during refrigerated storage (4±1ºC) for 10 days. Methods: In this study, 10 grams of raw beef meat were added to 90 milliliters of sterile buffered peptone water and homogenized in a stomacher for two minutes. Proper decimal dilutions were prepared in buffered peptone water for microbial enumeration. S. typhimurium was cultured on Salmonella Shigella agar and incubated at the temperature of 37ºC for 24 hours. In addition, L. monocytogenes was cultured on PALCAM listeria-selective agar and incubated at the temperature of 30ºC for 48 hours, and S. aureus was cultured on Baird-Parker agar and incubated at the temperature of 37ºC for 48 hours. Results: In all the experiments, no growth was observed in L. monocytogenes, S. typhimurium, and S. aureus in the non-inoculated control samples. Antimicrobial effects were more significant at the higher concentrations of OE (

Chicken meat hamburger preservation using antimicrobial packaging containing cinnamon extract

Introduction: Raw meat is recognized as one of the most vulnerable foodstuffs. The present study aimed to assess the preservation of raw chicken hamburger coated with the blends of chitosan (CH) and gelatin (GE), activated with 1% cinnamon extract (CE) and stored in refrigerated conditions for 10 days.Methods: The chicken hamburger samples (10 g) were aseptically cut and mixed in a stomacher with 90 milliliters of sterile buffered peptone water for two minutes. The proper dilution was inoculated onto microbiological plates, including Baird-Parker agar (Staphylococcus aureus), violet red bile glucose (VRBG) agar (total coliforms), and plate count agar (aerobic plate count (APC)). Peroxide value (PV) analysis was also performed based on standard method.Results: On sampling days zero, two, four, six, eight and ten, all the samples coated with edible films (especially those enriched with 1% CE) had excellent effectiveness against lipid oxidation compared to uncoated samples. After 10 days of storage, all the films could effectively decrease the growth of Staphylococcus aureus, total coliforms, and aerobic plate count (APC) in chicken hamburgers compared to controls (

Comparative Screening of Chloramphenicol Residue in Chicken Tissues Using Four Plate Test and Premi®Test Methods

Background: The safety of food with animal origin means that the food consumed is considered as safe when synthetic chemical agents are absent or present at very low concentrations. The aims of the present study were to validate the Premi®Test and four plate test (FPT) methods as well as screen and estimate the occurrence of chloramphenicol (CAP) residue in collected chicken tissues including liver, kidney and thigh muscle from Kermanshah, west of Iran. Methods: A total of 150 chicken samples were purchased from different poultry slaughterhouses in Kermanshah province, west of Iran and subjected to the FPT and Premi®Test. Results: The Premi®Test could not detect CAP residue at concentrations below 3 and 6 ppm in aqueous solution and kidney fluid, respectively. The highest sensitivity of FPT in the detection of CAP residue was optimally found in the agar medium inoculated with Bacillus subtilis at pH 7.2. The Premi®Test was more sensitive than FPT in the kidney fluid and aqueous solution. Regarding FPT results, CAP residue was found in 20% (n=30), 8.66% (n=28) and 11.33% (n=17) of liver, kidney and muscle samples, respectively. In the case of Premi®Test, the most contaminated samples were liver (24%), followed by kidney (22.66%) and muscle (19.33%). Conclusion: It can be concluded that illegal use of CAP in Iranian poultry industries should be taken into account seriously

Antibacterial and Antioxidant Properties of Scrophularia Striata Boiss. Methanolic Extract

Scrophularia striata belongs to the Scrophulariaceae family and widely grows in the several regions throughout the world especially Iran, Turkey and Azerbaijan. The aims of the present study were to evaluate antibacterial activity of the S. striata methanolic extract collected from west part of Iran by micro-broth dilution and agar disk diffusion assays, and also determine its antioxidant properties using 1, 1-diphenyl-2-picrylhydrazyl (DPPH) and thiobarbituric acid (TBA) methods. The most antibacterial activity was observed against Bacillus cereus, followed by B. subtilis, S. aureus. Listeria monocytogenes, Salmonella typhimurium and Escherichia coli O157:H7, respectively. Moreover, the scavenging properties on DPPH radical scavenging and TBA of S. striata methanolic extract were found to be 0.92 ± 0.21 and 7.98 ± 0.23, respectively. The strong in vitro antibacterial and antioxidant activities of S. striata methanolic extract supports its traditional application in the treatments and/or prevention of different diseases

Effects of Ziziphora clinopodioides Essential Oil and Nisin on the Microbiological Properties of Milk

Background: Recently, because of increasing concern regarding food safety containing chemical additives, remarkable attempts have been made and progress to develop natural antibacterial compounds such as essential oils. Methods: This study was conducted to determine antibacterial activities of Ziziphora clinopodioides essential oil (ZEO) alone and in combination with different concentrations of nisin to increase shelf life and control Salmonella typhimurium and Staphylococcus aureus in milk stored at refrigerated temperature. Results: The dominant constituents of ZEO in our study were carvacrol (65.22%) and thymol (19.51%). The microbial population was decreased significantly with addition of ZEO and nisin, increased their concentrations and longer storage time. It was found that milk samples containing ZEO at 0.2% and nisin at 500 IU mL-1 had significantly lower microbial population (p<0.05). Conclusions: Based on our findings, ZEO and nisin extended the shelf life of milk and may be used as natural antibacterial compounds in food products such as milk and dairy products

Variation in Chemical Composition of Essential Oil of Ferulago angulata Collected from West Parts of Iran

Background: Knowledge of diversity and variability of different plants is a main prerequisite and the first step in extraction of main compounds of them. The objective of the current research was to investigate main chemical composition of the essential oils of Ferulago angulata (Schlecht.) Boiss aerial parts collected from western parts of Iran (Kurdestan, Kermanshah and Lorestan provinces). Methods: Identification of the essential oils was performed by analytical gas chromatograph coupled with mass spectrometer detector (GC/MS). Results: The major compounds of essential oils of the aerial parts of plants were α-pinene (25.82%), Z-β-ocimene (23.48%), bornyl acetate (9.94%), germacrene D (4.01%), myrcene (3.06%), ɣ-terpinene (3%), limonene (2.27%) and p-cymene (1.99%). Conclusions: Our findings indicate that the main components of the essential oils belong to monoterpene hydrocarbons, oxygenated monoterpenes and sesquiterpene hydrocarbons

Ziziphora clinopodioides Essential Oil and Nisin as Potential Antimicrobial Agents against Escherichia coli O157:H7 in Doogh (Iranian Yoghurt Drink)

The aim of the present study was to evaluate the effects of Ziziphora clinopodioides essential oil (0.1 and 0.2%) and nisin (250 and 500 IU/mL) separately and in combination on survival of Escherichia coli O157:H7 inoculated in Doogh (Iranian yoghurt drink) during storage under refrigerated temperature (4 ± 1°C) for 9 days. Viability of Lactobacillus casei at different concentrations of Z. clinopodioides essential oil (0.1 and 0.2%) in Doogh was also examined. The major components were carvacrol (64.22%), thymol (19.22%), γ-terpinene (4.63%), and p-cymene (4.86%). There was no significant difference (p>0.05) between samples treated with nisin and those of untreated samples. Samples treated with both concentrations of the essential oil (0.1 and 0.2%) showed populations of E. coli O157:H7 significantly (p<0.05) lower than those of untreated samples. The essential oil of Z. clinopodioides in combination with nisin had a potential synergistic effect against E. coli O157:H7 in Doogh samples after 5 days. The count of L. casei was not inhibited by different concentrations of the Z. clinopodioides essential oil. It is concluded that the leaf essential oil of Z. clinopodioides in combination with nisin can be applied as alternative antimicrobial agents in Doogh to inhibit the growth of E. coli O157:H7

Antibacterial and Antioxidant Properties of Methanolic Extracts of Apple (Malus pumila), Grape (Vitis vinifera), Pomegranate (Punica granatum L.) and Common Fig (Ficus carica L.) Fruits

Background: As people demand to consume natural foods due to health concerns, the investigation of natural compounds for the discovery of new constituents with antibacterial and antioxidant properties is increasing. The aim of the present study was to evaluate antioxidant and antibacterial activities of some fruits including apple (Malus pumila), grape (Vitis vinifera), pomegranate (Punica granatum L.) and common fig (Ficus carica L.) produced in Kermanshah, west of Iran. Methods: The antibacterial activity of fruit extracts were examined by broth micro-dilution and agar disk diffusion methods. Their antioxidant activity were measured using 1,1-diphenyl-2-picrylhydrazyl (DPPH), ferric reducing antioxidant power, β-carotene/linoleic acid bleaching and thiobarbituric acid (TBA) methods. The contents of total phenolic (TP) and total flavonoid (TF) of extracts were determined using Folin Ciocalteu and colorimetric methods, respectively. Results: The highest and lowest antibacterial effects were found for P. granatum and F. carica extracts, respectively. The most antibacterial effect was observed against Bacillus subtilis, followed by B. cereus and Staphylococcus aureus, respectively. The similar sensitivity was observed for Listeria monocytogenes, Salmonella typhimurium and Escherichia coli O157:H7. P. granatum extract had a significant higher DPPH radical scavenging (0.16 ± 0.07 mg/ml), ability to prevent the bleaching of β-carotene (0.09 ± 0.01 mg/ml), ferric reducing power (0.33 ± 0.03 mg/ml) and TBA (0.27 ± 0.01 Meq malondialdehyde/g) values. The highest TP and TF were found in P. granatum, followed by V. vinifera, M. pumila, and F. carica, respectively, which were in consistent with the results of antioxidant and antibacterial properties. Conclusions: The strong in vitro antioxidant activities of investigated fruit extracts support their traditional application in the treatment and/or prevention of different diseases