Anti-Salmonella Activity of Thymus serpyllum Essential Oil in Sous Vide Cook-Chill Rabbit Meat.

Food is generally prepared and vacuum-sealed in a water bath, then heated to a precise temperature and circulated in a sous vide machine. Due to its affordability and ease of use, this cooking method is becoming increasingly popular in homes and food service businesses. However, suggestions from manufacturers and chefs for long-term, low-temperature sous vide cooking raise questions about food safety in the media. In this study, heat treatment with different times and wild thyme essential oil (EO) in sous vide-processed rabbit longissimus dorsi muscle were found to inactivate Salmonella enterica. The rabbit meat samples were vacuum-packed in control groups, in the second group the rabbit meat samples were injected with S. enterica, and in the third group were meat samples infected with S. enterica with Thymus serpylum EO additive. The vacuum-packed samples were cooked sous vide for the prescribed time at 55, 60, and 65 °C. At 5, 15, 30, and 60 min, the quantities of S. enterica, total bacterial counts, and coliform bacteria were measured in groups of sous vide rabbit meat. Microbiological analyses of rabbit meat samples on days 1 and 7 were evaluated. In this study, total viable counts, coliforms bacteria, and number of Salmonella spp. were identified. After incubation, isolates from different groups of microorganisms were identified by the mass spectrometry technique. For each day measured, the test group exposed to a temperature of 55 °C for 5 min had a greater number of total microbiota. The most isolated microorganisms by MALDI-TOF MS Biotyper from the control and treated groups were Lactococcus garvieae and in the treated groups also S. enterica. Based on our analysis of sous vide rabbit meat samples, we discovered that adding 1% of thyme essential oil to the mixture reduced the amount of Salmonella cells and increased the overall and coliform bacterial counts. The microbiological quality of sous vide rabbit meat that was kept for seven days was positively impacted by the addition of thyme essential oil.

Thymus zygis, Valuable Antimicrobial (In Vitro and In Situ) and Antibiofilm Agent with Potential Antiproliferative Effects.

With the growing issues of food spoilage, microbial resistance, and high mortality caused by cancer, the aim of this study was to evaluate T. zygis essential oil (TZEO) as a potential solution for these challenges. Here, we first performed GC/MS analysis which showed that the tested TZEO belongs to the linalool chemotype since the abundance of linalool was found to be 38.0%. Antioxidant activity assays showed the superiority of TZEO in neutralizing the ABTS radical cation compared to the DPPH radical. The TZEO was able to neutralize 50% of ABTS•+ at the concentration of 53.03 ± 1.34 µg/mL. Antimicrobial assessment performed by employing disc diffusion and minimal inhibitory concentration assays revealed TZEO as a potent antimicrobial agent with the highest inhibition activity towards tested gram-negative strains. The most sensitive on the treatment with TZEO was Enterobacter aerogenes showing an MIC 50 value of 0.147 ± 0.006 mg/mL and a MIC 90 value of 0.158 ± 0.024 mg/mL. Additionally, an in situ analysis showed great effects of TZEO in inhibiting gram-negative E. coli, P. putida, and E. aerogenes growing on bananas and cucumbers. Treatment with the TZEO vapor phase in the concentration of 500 µg/mL was able to reduce the growth of these bacteria on the food models to the extent > 90%, except for E. coli growth on the cucumber, which was reduced to the extent of 83.87 ± 4.76%. Furthermore, a test on the antibiofilm activity of the tested essential oil revealed its biofilm prevention effects against Salmonella enterica which forms biofilms on plastic and stainless-steel surfaces. Performed tests on the TZEO effects towards cell viability showed no effects on the normal MRC-5 cell line. However, the results of MTT assay of TZEO effects on three cancer cell lines (MDA-MB-231, HCT-116, and K562) suggest that TZEO exerted the strongest effects on the inhibition of the viability of MDA-MB-231 cells, especially after long-term treatment in the highest concentration applied with reducing the viability of the cells to 57%. Additionally, results of NBT and Griess assays suggest that TZEO could be a convenient candidate for future testing for developing novel antitumor therapies.

An In-Depth Study on the Chemical Composition and Biological Effects of Pelargonium graveolens Essential Oil.

The essential oil of Pelargonium graveolens (PGEO) is identified in the literature as a rich source of bioactive compounds with a high level of biological activity. This study aimed to examine the chemical profile of PGEO as well as its antioxidant, antibacterial, antibiofilm, and insecticidal properties. Its chemical composition was analyzed using gas chromatography-mass spectrometry (GC-MS), achieving comprehensive identification of 99.2% of volatile compounds. The predominant identified compounds were ß-citronellol (29.7%) and geraniol (14.6%). PGEO's antioxidant potential was determined by means of DPPH radical and ABTS radical cation neutralization. The results indicate a higher capacity of PGEO to neutralize the ABTS radical cation, with an IC50 value of 0.26 ± 0.02 mg/mL. Two techniques were used to assess antimicrobial activity: minimum inhibitory concentration (MIC) and disk diffusion. Antimicrobial evaluation using the disk diffusion method revealed that Salmonella enterica (14.33 ± 0.58 mm), which forms biofilms, and Priestia megaterium (14.67 ± 0.58 mm) were most susceptible to exposure to PGEO. The MIC assay demonstrated the highest performance of this EO against biofilm-forming S. enterica (MIC 50 0.57 ± 0.006; MIC 90 0.169 ± 0.08 mg/mL). In contrast to contact application, the assessment of the in situ vapor phase antibacterial activity of PGEO revealed significantly more potent effects. An analysis of antibiofilm activity using MALDI-TOF MS demonstrated PGEO's capacity to disrupt the biofilm homeostasis of S. enterica growing on plastic and stainless steel. Additionally, insecticidal evaluations indicated that treatment with PGEO at doses of 100% and 50% resulted in the complete mortality of all Harmonia axyridis individuals.

Microbiological Quality of Deer Meat Treated with Essential Oil Litsea cubeba.

The present study aimed to evaluate deer meat microbiological quality when treated with essential oil (EO) from Litsea cubeba (dissolved in rapeseed oil at concentrations 0.5 and 1%), in combination with vacuum packaging during 20 days of storage of meat at 4 °C. Total viable counts (TVC), coliforms bacteria (CB), lactic acid bacteria (LAB) and Pseudomonas spp. were analysed at day 0, 1, 5, 10, 15 and 20. MALDI-TOF MS Biotyper technology was applied to identify microorganisms isolated from meat. The highest number of TVC at the end of the experiment was 5.50 log CFU/g in the aerobically packaged control group and the lowest number of TVC was 5.17 log CFU/g in the samples treated with 1.0% Litsea cubeba EO. CB were not detected in the samples treated with 1.0% Litsea cubeba EO during the entire storage period. Bacteria of the genus Pseudomonas were detected only in the aerobically and vacuum packaged control group. The highest number of LAB was 2.06 log CFU/g in the aerobic control group, and the lowest number of LAB was 2.01 log CFU/g in the samples treated with 1.0% Litsea cubeba EO on day 20. The most frequently isolated bacteria from deer meat were Pseudomonas ludensis, Pseudomonas corrugata, Pseudomonas fragi, Bacillus cereus, Staphylococcus epidermidis and Sphingomonas leidyi.

A novel Triticum durum Annexin 12 protein: Expression, purification and biological activities against Listeria monocytogenes growth in meat under refrigeration.

The present study was undertaken to investigate the expression, purification and biological activities of a novel Triticum durum Annexin 12 protein (TdAnn12). The findings indicated that the molecular weight of the purified TdAnn12 was estimated to 35 kDa. The purified TdAnn12 protein was modulated by, Methyl-jasmonate, and ethephon treatments. The purified TdAnn12 protein displayed good antimicrobial activities against 9 tested pathogenic bacteria. The antioxidant activities showed that TdAnn12 displayed an excellent DPPH scavenging ability with an IC50 of 8.33 µg/ml and a strong Beta-carotene bleaching inhibition after 120 min of incubation with an IC50 of 2 µg/ml the cytotoxic effects of the TdAnn 12 showed that HepG2 and MCF-7 were examined by MTT assay. The IC50 values were 250.35 and 400.25 µg/ml for HepG2 and MCF-7 cells, respectively. The inhibitory effects of this TdAnn12 was assessed in vivo against Listeria monocytogenes, inoculated in minced beef meat at 6.105 CFU/g amended with different concentrations of the purified TdAnn12 and stored at 4 °C for 21 days. Results showed an excellent inhibitory effect of TdAnn12 of this pathogenic bacterium at 4 °C. Overall, the TdAnn12 have potential application as active ingredients in food and pharmaceutical industry.

Chemical Composition and in vivo Efficacy of the Essential Oil of Mentha piperita L. in the Suppression of Crown Gall Disease on Tomato Plants.

This study was undertaken to determine the antibacterial efficacy of the essential oil (EO) of peppermint (Mentha piperita L.), in vitro and in vivo, against the phytopathogenic bacteria Agrobacterium tumefaciens (A. tumefaciens). The EO composition of M. piperita L. was investigated by Gas chromatography-mass spectrometry (GC/MS) with 26 identified volatile constituents. The major constituents were menthol (33.59%) and iso-menthone (33.00%). This EO exerted a bactericidal activity against multiple strains of Agrobacterium species with minimum inhibitory concentration (MIC) values ranged from 0.01 to 12.50 mg/mL. In planta experiments, M. piperita EO, tested at concentration of 200 mg/mL, completely inhibited the formation of tumors on tomato plants inoculated with pathogenic strain A. tumefaciens ATCC 23308T. These results suggest that M. piperita EO could be used to control plant bacterial disease caused by A. tumefaciens.

Essential oil from halophyte Lobularia maritima: protective effects against CCl4-induced hepatic oxidative damage in rats and inhibition of the production of proinflammatory gene expression by lipopolysaccharide-stimulated RAW 264.7 macrophages.

The present study evaluates the chemical profiling of the essential oil of a halophyte, L. maritima (LmEO), and its protective potential against CCl4-induced oxidative stress in rats. Forty compounds have been identified in LmEO. The major components are α-pinene (3.51%), benzyl alcohol (8.65%), linalool (22.43%), pulegone (3.33%), 1-phenyl butanone (7.33%), globulol (4.32%), γ-terpinene (6.15%), terpinen-4-ol (4.31%), α-terpineol (3.9%), ledol (3.59%), epi-α-cadinol (3.05%) and α-cadinol (4.91%). In comparison with the CCl4-intoxicated group, LmEO treatment resulted in decreased liver serum marker enzymes, decreased lipid peroxidation and increased antioxidant enzyme levels, with overall further amelioration of oxidative stress. The administration of LmEO to CCl4-treated rats at a dose of 250 mg kg-1 body weight significantly reduced the toxic effects and the oxidative stress on the liver, thus validating the traditional medicinal claim of this plant. Moreover, the anti-inflammatory activity of LmEO was evaluated in lipopolysaccharide-stimulated murine RAW 264.7 cells. Our oil could modulate the inflammatory mode of the macrophages by causing reduction in iNOS and COX2 enzymes as well as in IL-1ß, IL-6, and TNF-α cytokine levels. These findings suggest that LmEO exerts anti-inflammatory effects by regulating the expression of inflammatory cytokines.

A stress-associated protein, LmSAP, from the halophyte Lobularia maritima provides tolerance to heavy metals in tobacco through increased ROS scavenging and metal detoxification processes.

Agricultural soil pollution by heavy metals is a severe global ecological problem. We recently showed that overexpression of LmSAP, a member of the stress-associated protein (SAP) gene family isolated from Lobularia maritima, in transgenic tobacco led to enhanced tolerance to abiotic stress. In this study, we characterised the response of LmSAP transgenic tobacco plants to metal stresses (cadmium (Cd), copper (Cu), manganese (Mn), and zinc (Zn)). In L. maritima, LmSAP expression increased after 12 h of treatment with these metals, suggesting its involvement in the plant response to heavy metal stress. LmSAP transgenic tobacco plants subjected to these stress conditions were healthy, experienced higher seedling survival rates, and had longer roots than non-transgenic plants (NT). However, they exhibited higher tolerance towards cadmium and manganese than towards copper and zinc. LmSAP-overexpressing tobacco seedlings accumulated more cadmium, copper, and manganese compared with NT plants, but displayed markedly decreased hydrogen peroxide (H2O2) and lipid peroxidation levels after metal treatment. Activities of the antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD) were significantly higher in transgenic plants than in NT plants after exposure to metal stress. LmSAP overexpression also enhanced the transcription of several genes encoding metallothioneins (Met1, Met2, Met3, Met4, and Met5), a copper transport protein CCH, a Cys and His-rich domain-containing protein RAR1 (Rar1), and a ubiquitin-like protein 5 (PUB1), which are involved in metal tolerance in tobacco. Our findings indicate that LmSAP overexpression in tobacco enhanced tolerance to heavy metal stress by protecting the plant cells against oxidative stress, scavenging reactive oxygen species (ROS), and decreasing the intracellular concentration of free heavy metals through its effect on metal-binding proteins in the cytosol.

Bio-preservative effect of the essential oil of the endemic Mentha piperita used alone and in combination with BacTN635 in stored minced beef meat.

The major compounds in Mentha piperita essential oil (EOMP) were menthol (33.59%) and iso-menthone (33%). The biopreservative effect of EOMP used alone at 0.25 or 0.5% and in combination with the semi-purified bacteriocin BacTN635 at 500 or 1000AU/g, on minced beef meat was evaluated by microbiological, physicochemical and sensory analyses during storage at 4°C for 21days. EOMP used alone limited the microbial deterioration of minced meat (P<0.05). Furthermore, the combination between EOMP and BacTN635 led to a decrease in TBARS values and slowed down the accumulation of MetMb. This combination was more efficient (P<0.05) against microflora proliferation and enhanced the sensory acceptability extending thus the shelf life of meat beef by approximately 7days. On the basis of these results, physicochemical and sensorial parameters could be used for constructing regression models to predict overall acceptability. Overall, the strongest preservative effect was achieved by using the combination of EOMP at 0.5% with BacTN535 at 1000AU/g.

Ruta montana L. leaf essential oil and extracts: characterization of bioactive compounds and suppression of crown gall disease.

The aims of this study were to assess the antimicrobial efficacy of the leaf essential oil and the leaf extracts of R. montana against Botrytis cinerea, Fusarium oxysporum, Verticillium dahliae, Aspergillus oryzae and Fusarium solani. The oil (1.000 µg/disk) and the extracts (1.500 µg/disk) revealed a remarkable antifungal effect against the tested plant pathogenic fungi with a radial growth inhibition percentage of 40.0-80.0 % and 5.0-58.0 %, respectively along with their respective MIC values ranging from 100 to 1100 µg/mL and 250 to 3000 µg/mL. The oil had a strong detrimental effect on spore germination of all the tested plant pathogens along with the concentration as well as time-dependent kinetic inhibition of Fusarium oxysporum. Also, the oil exhibited a potent in vivo antifungal effect against Botrytis cinerea on tomato plants. Experiments carried out in plant revealed that the essential oil was slightly effective in suppression of gall formation induced by Agrobacterium tumefaciens on bitter almond. The results of this study indicate that the oil and extracts of R. montana leaves could become natural alternatives to synthetic fungicides to control certain important plant microbial diseases. The GC-MS analysis determined that 28 compounds, which represented 89.03 % of total oil, were present in the oil containing mainly 1-butene, methylcyclopropane, 2-butene and caryophyllene oxide.

Chemical composition, cytotoxicity effect and antimicrobial activity of Ceratonia siliqua essential oil with preservative effects against Listeria inoculated in minced beef meat.

The present study describes the phytochemical profile and the protective effects of Ceratonia siliqua pods essential oil (CsEO), a food and medicinal plant widely distributed in Tunisia. Twenty five different components were identified in the CsEO. Among them, the major detected components were: Nonadecane, Heneicosane , Naphthalene, 1,2-Benzenedicarboxylic acid dibutylester, Heptadecane, Hexadecanoic acid, Octadecanoic acid, 1,2-Benzenedicarboxylic acid, Phenyl ethyl tiglate, Eicosene, Farnesol 3, Camphor, Nerolidol and n-Eicosane. The antimicrobial activity of CsEO was evaluated against a panel of 13 bacteria and 8 fungal strains using agar diffusion and broth microdilution methods. Results have shown that CsEO exhibited moderate to strong antimicrobial activity against the tested species. In addition, the inhibitory effect of this CsEO was evaluated in vivo against a foodborne pathogens Listeria monocytogenes, experimentally inoculated in minced beef meat (2×10(2) CFU/g of meat) amended with different concentrations of the CsEO and stored at 7 °C for 10 days. The antibacterial activity of CsEO in minced beef meat was clearly evident and its presence led to a strong inhibitory effect against the pathogens at 7 °C. On the other hand, the cytotoxic effects of the essential oil against two tumoral human cell lines HeLa and MCF-7 were examined by MTT assay. The CsEO showed an inhibition of both cell lines with significantly stronger activity against HeLa cells. The IC(50) values were 210 and 800 µg/ml for HeLa and MCF-7 cells, respectively. Overall, results presented here suggest that the EO of C. siliqua possesses antimicrobial and cytotoxic properties, and is therefore a potential source of active ingredients for food and pharmaceutical industry.