Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “THYME”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 127 records · Page 7Linked to original sources

Effectiveness of immersion treatments with acids, trisodium phosphate, and herb decoctions in reducing populations of Yarrowia lipolytica and naturally occurring aerobic microorganisms on raw chicken.

Yarrowia lipolytica, one of the predominant yeasts in raw poultry, is believed to play a role in spoilage. This study was undertaken to investigate treatments to control the growth of Y. lipolytica on raw chicken stored at refrigeration temperature. Raw chicken wings inoculated with a mixture of five strains of Y. lipolytica isolated from raw poultry were dipped in solutions containing 2, 5, or 8% lactic acid, 2% lactic acid containing 0.2, 0.4, or 0.8% potassium sorbate or sodium benzoate, and 4, 8, or 12% trisodium phosphate solution. Populations of the yeast and total aerobic microorganisms were determined before and after treatment. Immersion of wings in 2% lactic acid (with or without 0.2% potassium sorbate or sodium benzoate) or 4% trisodium phosphate caused a significant (alpha = 0.05) reduction in numbers of Y. lipolytica and aerobic microorganisms. Treatment with 2% lactic acid containing 0.4 or 0.8% preservative did not result in additional significant reductions. Treatment of chicken wings with 2% lactic acid or 8% trisodium phosphate significantly reduced numbers of Y. lipolytica by 1.47 and 0.65 log10 cfu/g, respectively, and aerobic microorganisms by 2.60 and 1.21 log10 cfu/g, respectively, compared to controls. Growth of Y. lipolytica on wings stored at 5 degrees C for up to 9 days, however, was not affected by these treatments. Significant reductions in the population of Y. lipolytica occurred when the yeast was inoculated into 100% basil, marjoram, sage, and thyme decoctions, but not in 100% oregano or rosemary decoctions, held at 5 degrees C for 24 h. Treatment of chicken wings with 100% sage or thyme decoctions significantly reduced populations of Y. lipolytica but did not control its growth during storage at 5 degrees C for up to 9 days. The small, temporary decreases in numbers of Y. lipolytica and aerobic microorganisms resulting from immersion treatment of chicken wings with sage and thyme decoctions render these treatments of questionable value as preservation interventions.

Animals↗

Combined effect of antimicrobial coating and gamma irradiation on shelf life extension of pre-cooked shrimp (Penaeus spp.).

The present study was conducted to evaluate the combined effect of low-dose gamma irradiation and antimicrobial coating on the shelf life of pre-cooked shrimp (Penaeus spp.). Antimicrobial coatings were obtained by incorporating various concentrations of thyme oil and trans-cinnamaldehyde in coating formulations prepared from soy or whey protein isolates. Coated shrimps were stored at 4 +/- 1 degrees C under aerobic conditions and were periodically evaluated for aerobic plate counts (APCs) and Pseudomonas putida. Sensory evaluations were performed for appearance, odor, and taste using a hedonic test. Results showed that gamma irradiation and coating treatments had synergistic effects (p < or = 0.05) in reducing the APCs and P. putida with at least a 12-day extension of shelf life. Without irradiation, the inhibitory effects of the coating solutions were closely related to the concentration of thyme oil and trans-cinnamaldehyde. No detrimental effects of gamma irradiation on organoleptic parameters (appearance, odor, and taste) were observed. However, incorporation of thyme oil and trans-cinnamaldehyde reduced the acceptability scores for taste and odor.

Animals↗

Effect of oil extracted from some medicinal plants on different mycotoxigenic fungi.

Essential oils of 12 medicinal plants were tested for inhibitory activity against Aspergillus flavus, A. parasiticus, A. ochraceus and Fusarium moniliforme. The oils of thyme and cinnamon (< or = 500 ppm), marigold (< or = 2000 ppm), spearmint, basil, quyssum (3000 ppm) completely inhibit all the test fungi. Caraway was inhibitory at 2000 ppm against A. flavus, A. parasiticus and 3000 ppm against A. ochraceaus and F. moniliforme. A. flavus, A. ochraceus, A. parasiticus and F. moniliforme were completely inhibited by anise at< or = 500 ppm. However, chamomile and hazanbul at all concentrations were partially effective against the test toxigenic fungi. The results indicate that the test toxigenic fungi are sensitive to the 12 essential oils, and particularly sensitive to thyme and cinnamon. The results also showed that the essential oils of thyme, cinnamon, anise and spearmint have more effect on fungal development and subsequent mycotoxin production in wheat grains. The extent of inhibition of fungal growth and mycotoxin production was dependent on the concentration of essential oils used.

Antifungal Agents↗

Antifungal activity of essential oils evaluated by two different application techniques against rye bread spoilage fungi.

AIMS: To study how antifungal activity of natural essential oils depends on the assay method used. METHODS AND RESULTS: Oils of bay, cinnamon leaf, clove, lemongrass, mustard, orange, sage, thyme and two rosemary oils were tested by two methods: (1) a rye bread-based agar medium was supplemented with 100 and 250 microl l-1 essential oil and (2) real rye bread was exposed to 136 and 272 microl l-1 volatile oil in air. Rye bread spoilage fungi were used for testing. Method 1 proved thyme oil to be the overall best growth inhibitor, followed by clove and cinnamon. On the contrary, orange, sage and rosemary oils had very limited effects. Mustard and lemongrass were the most effective oils by the volatile method, and orange, sage and one rosemary showed some effects. Oil compositions were analysed by gas chromatography-mass spectrography. CONCLUSIONS: Antifungal effects of the essential oils depended on the application method. Larger phenolic compounds such as thymol and eugenol (thyme, cinnamon and clove) had best effect applied directly to medium, whereas smaller compounds such as allyl isothiocyanate and citral (mustard and lemongrass) were most efficient when added as volatiles. SIGNIFICANCE AND IMPACT OF THE STUDY: This study proves that the method used for screening essential oils as potential antimicrobials should correspond with the application sought.

Antifungal Agents↗

In-vitro and in-vivo anti-Trichophyton activity of essential oils by vapour contact.

The minimum inhibitory doses (MIDs) of essential oils by vapour contact to inhibit the growth of Trichophyton mentagrophytes and Trichophyton rubrum on agar medium were determined using airtight boxes. Among seven essential oils examined, cinnamon bark oil showed the least MID, followed by lemongrass, thyme and perilla oils. Lavender and tea tree oils showed moderate MID, and citron oil showed the highest MID, being 320 times higher than that of cinnamon bark oil. The MID values were less than the minimum inhibitory concentration (MIC) values determined by agar dilution assay. Furthermore, the minimum agar concentration (MAC) of essential oils absorbed from vapour was determined at the time of MID determination as the second antifungal measure. The MAC value by vapour contact was 1.4 to 4.7 times less than the MAC remaining in the agar at the time of MIC determination by agar dilution assay. Using selected essential oils, the anti-Trichophyton activity by vapour contact was examined in more detail. Lemongrass, thyme and perilla oils killed the conidia, inhibited germination and hyphal elongation at 1-4 micrograms ml-1 air, whereas lavender oil was effective at 40-160 micrograms ml-1 air. The in-vivo efficacy of thyme and perilla oils by vapour contact was shown against an experimental tinea pedis in guinea pigs infected with T. mentagrophytes. These results indicated potent anti-Trichophyton action of essential oils by vapour contact.

Agar↗

In-vitro antimicrobial activity and chemical composition of Sardinian Thymus essential oils.

Essential oils and their components are becoming increasingly popular as naturally occurring antimicrobial agents. In this work the chemical composition and the antimicrobial properties of Thymus essential oils and of their main components were determined. Three essential oils obtained from different species of Thymus growing wild in Sardinia and a commercial sample of Thymus capitatus oil were analysed. The essential oil components were identified by GC/MS analysis. The antimicrobial activity of the oils and components was determined against a panel of standard reference strains and multiple strains of food-derived spoilage and pathogenic bacteria, using a broth microdilution method. The GC/MS analysis showed that the major constituents of the oils were monoterpene hydrocarbons and phenolic monoterpenes, but the concentration of these compounds varied greatly among the oils examined. The results of the antimicrobial assay showed that essential oils extracted from Sardinian Thymus species have an antimicrobial activity comparable to the one observed in other thyme oils. It seems also confirmed that the antimicrobial properties of thyme essential oils are mainly related to their high phenolic content. Among the single compounds tested carvacrol and thymol turned out to be the most efficient against both reference strains and food-derived bacteria. The results of this study confirmed the possibility of using thyme essential oils or some of their components in food systems to prevent the growth of foodborne bacteria and extend the shelf-life of processed foods.

Anti-Bacterial Agents↗

Antibacterial activity of selected plant essential oils against Escherichia coli O157:H7.

AIMS: To quantify the antibacterial properties of five essential oils (EO) on a non-toxigenic strain of Escherichia coli O157:H7 in the presence and absence of a stabilizer and an emulsifier and at three different temperatures. METHODS AND RESULTS: Five EOs known to exhibit antibacterial properties were screened by disc diffusion assay and the most active were selected for further study in microdilution colorimetric assays. Oregano (Origanum vulgare) and thyme (Thymus vulgaris; light and red varieties) EO had the strongest bacteriostatic and bactericidal properties, followed by bay (Pimenta racemosa) and clove bud (Eugenia caryophyllata synonym: Syzygium aromaticum) EO. Oregano oil was colicidal at 625 microl l(-1) at 10, 20 and 37 degrees C. The addition of 0.05% (w/v) agar as stabilizer reinforced the antibacterial properties, particularly at 10 degrees C, whereas 0.25% (w/v) lecithin reduced antibacterial activity. Scanning electron micrographs showed extensive morphological changes to treated cells. CONCLUSIONS: Oregano and thyme EO possess significant in vitro colicidal and colistatic properties, which are exhibited in a broad temperature range and substantially improved by the addition of agar as stabilizer. Bay and clove bud EO are less active. Lecithin diminished antibacterial properties. The bactericidal concentration of oregano EO irreversibly damaged E. coli O157:H7 cells within 1 min. SIGNIFICANCE AND IMPACT OF THE STUDY: Oregano and light thyme EO, particularly when enhanced by agar stabilizer, may be effective in reducing the number or preventing the growth of E. coli O157:H7 in foods.

Agar↗

Effect of spice hydrosols on the growth of Aspergillus parasiticus NRRL 2999 strain.

The inhibitory effects of 16 spice hydrosols [anise, basil, cumin, dill, Aegean sage, fennel (sweet), laurel, mint, oregano, pickling herb, rosemary, sage, savory, sea fennel, sumac, and thyme (black)] on the mycelial growth of Aspergillus parasiticus strain NRRL 2999 were investigated in vitro. The hydrosols of anise, cumin, fennel, mint, pickling herb, oregano, savory, and thyme showed a stronger inhibitory effect on mycelial growth, while sumac, sea fennel, rosemary, sage, Aegean sage, laurel, basil, and rosemary hydrosols were unable to inhibit totally the growth. Of these, sumac had the least effect on the mycelial growth of A. parasiticus. The effectiveness of the inhibitors followed the sequence anise = cumin = fennel = mint = pickling herb = oregano = savory = thyme > laurel > dill > sage > rosemary > basil > sea fennel > rosemary > sumac.

Antifungal Agents↗

Systemic availability and pharmacokinetics of thymol in humans.

Essential oil compounds such as found in thyme extract are established for the therapy of chronic and acute bronchitis. Various pharmacodynamic activities for thyme extract and the essential thyme oil, respectively, have been demonstrated in vitro, but availability of these compounds in the respective target organs has not been proven. Thus, investigation of absorption, distribution, metabolism, and excretion are necessary to provide the link between in vitro effects and in vivo studies. To determine the systemic availability and the pharmacokinetics of thymol after oral application to humans, a clinical trial was carried out in 12 healthy volunteers. Each subject received a single dose of a Bronchipret TP tablet, which is equivalent to 1.08 mg thymol. No thymol could be detected in plasma or urine. However, the metabolites thymol sulfate and thymol glucuronide were found in urine and identified by LC-MS/MS. Plasma and urine samples were analyzed after enzymatic hydrolysis of the metabolites by headspace solid-phase microextraction prior to GC analysis and flame ionization detection. Thymol sulfate, but not thymol glucuronide, was detectable in plasma. Peak plasma concentrations were 93.1+/-24.5 ng ml(-1) and were reached after 2.0+/-0.8 hours. The mean terminal elimination half-life was 10.2 hours. Thymol sulfate was detectable up to 41 hours after administration. Urinary excretion could be followed over 24 hours. The amount of both thymol sulfate and glucuronide excreted in 24-hour urine was 16.2%+/-4.5% of the dose.

Administration, Oral↗

Incorporation of thymol into corncob granules for reduction of odor and pathogens in feedlot cattle waste.

Confined animal feeding operations can be a source of odor emissions, global warming gases, water pollution, and food contamination. Laboratory studies have indicated that plant oils with antimicrobial activity can be used to control pathogens and odor emissions from cattle and swine wastes. However, these oils are aromatic and may volatilize when applied topically. Our objectives were to evaluate the volatility of thymol from a feedlot surface and the effectiveness of topically applying thyme oil (2.5% thymol), incorporated into corncob granules and added once per week, to control odor emissions and total coliforms in feedlot manure. In the first study, thymol either volatilized or was degraded within 28 d after topical application. In a second study, thyme oil (2.5% thymol) was incorporated into corncobs and applied to pen surfaces weekly. Manure samples from 6 locations in each pen were collected from 3 untreated and 3 thymol-corncob-treated pens (15 x 150 m; fifty 400-kg cattle/pen), 3 times per week for 8 wk. Samples were analyzed for thymol concentration, total VFA, branched-chain VFA, aromatic compounds, and the number of Escherichia coli and total coliform bacteria. Over the 8 wk, with the exception of wk 7, the desired thymol concentration of 15 to 20 micromol/g DM was maintained in the manure. Concentrations of VFA and branched chain-VFA increased over time in untreated and treated pens. However, the rate of VFA accumulation in treated pens (7.5 +/- 1.3 micromol.g DM(-1).wk(-1)) was less (P < 0.01) than the rate of accumulation in untreated pens (18.0 +/- 2.1 micromol.g DM(-1).wk(-1)). Likewise, the rate of branched-chain VFA accumulation in treated pens (0.31 +/- 0.04 micromol.g DM(-1).wk(-1)) was less (P < 0.01) than in untreated pens (0.55 +/- 0.06 micromol.g DM(-1).wk(1)). The concentrations of E. coli in treated pens (2.9 +/- 1.2 x 10(5) cfu.g DM(-1)) were 91% less (P < 0.04) than in untreated pens (31.1 +/- 4.0 x 10(5) cfu.g DM(-1)). Similarly, concentrations of coliforms in treated pens (3.7 +/- 1.3 x 10(5) cfu.g DM(-1)) were 89% less (P < 0.04) than those of untreated pens (35.3 +/- 4.2 x 10(5) cfu.g DM(-1)). These results indicate that odor emissions and total coliforms can be reduced in feedlot manure with a once per week application of thymol incorporated in a granular form. However, corncobs are bulky, and other granular carriers with a greater carrying capacity for thyme oil should be explored.

Animal Husbandry↗

Effects of selected plant essential oils on the growth and development of mouse preimplantation embryos in vivo.

Plant essential oils (EOs) have been reported to have health benefit properties and their preventive and therapeutic use in animals is expected to increase in the future. We evaluated the influence of five essential oils obtained from plant species which are known to have positive antimicrobial, antioxidative and anti-inflammatory effects--sage EO from Salvia officinalis L. (Lamiaceae), oregano EO from Origanum vulgare L. (Lamiaceae), thyme EO from Thymus vulgaris L. (Lamiaceae), clove EO from Syzygium aromaticum L. (Myrtaceae) and cinnamon EO from Cinnamomum zeylanicum Blume (Lauraceae) on the growth and development of mouse preimplantation embryos in vivo. Essential oils were added to commercial diet at concentrations of 0.25% for sage EO, thyme EO, clove EO, cinnamon EO and 0.1% for oregano EO, and fed to ICR female mice for 2 weeks ad libitum. Females were then mated with males of the same strain. Embryos obtained on Day 4 of pregnancy at the blastocyst stage were stained by morphological triple staining (Hoechst, PI, Calcein-AM) and evaluated using fluorescent microscopy. The effects of essential oils were estimated by the viability of embryos, number of nuclei and distribution of embryos according to nucleus number. Cinnamon EO significantly decreased the number of nuclei and the distribution of embryos according to nucleus number was significantly altered. Sage EO negatively influenced the distribution of embryos according to nucleus number. Clove and oregano EOs induced a significantly increased rate of cell death. Only thyme EO had no detectable effects on embryo development. In conclusion, none of the essential oils had any positive effect on embryo development, but some of them reduced the number of cells and increased the incidence of cell death.

Animals↗

Antimicrobial activity of the essential oils of Thymus vulgaris L. measured using a bioimpedometric method.

The essential oils obtained from Thymus vulgaris L. harvested at four ontogenetic stages were evaluated for their biological activity and chemical composition. The thyme essential oils were tested for their inhibitory effects against nine strains of gram-negative bacteria and six strains of gram-positive bacteria. The bioimpedance method was chosen for studying the antibacterial activity of the essential oils and the parameter chosen for defining and quantifying the antibacterial activity of the essential oils was the detection time. The plate counting technique was used to study the inhibitory effect by direct contact. All the thyme essential oils examined had a significant bacteriostatic activity against the microorganisms tested. This activity was more marked against the gram-positive bacteria. The oil from thyme in full flower was the most effective at stopping the growth of the microbial species examined. The oils tested were also shown to have good antibacterial activity by direct contact, which appeared to be more marked against the gram-negative bacteria. Only a few of the species were capable of recovering at least 50% of their metabolic function after contact with the inhibitor, while most of the strains were shown to have been inactivated almost completely. Escherichia coli O157:H7 was the most sensitive species, given that after contact with even the lowest concentration of oil cells could not be recovered.

Anti-Bacterial Agents↗

Fungitoxic activity of 12 essential oils against four postharvest citrus pathogens: chemical analysis of thymus capitatus oil and its effect in subatmospheric pressure conditions.

The fungitoxic activity against Penicillium digitatum, Penicillium italicum, Botrytis cinerea, and Alternaria citri of 12 essential oils (EOs) distilled from medicinal plants is reported. The results of the in vitro trials show strong fungitoxic activity of Thymus capitatus (L.) Hofmgg EOs, which inhibited the growth of the four fungi at a concentration of 250 ppm (vol/vol). The other 11 essences reduced the development of the fungi from 95 to 9% at 250 ppm (vol/vol). The fungitoxic activity of T. capitatus EOs (75, 150, and 250 ppm) on healthy orange fruits, inoculated with P. digitatum (10(8) conidia ml(-1)) by spraying and placed in 10-liter desiccators, was weak at atmospheric pressure (3 to 10% inhibition at all three concentrations), while in vacuum conditions (0.5 bar), conidial mortality on the exocarp was high (90 to 97% at all three concentrations). These data proved not to be statistically different from treatments with thiabendazole-TBZ (2,000 ppm). Scanning electron microscope observations showed that T. capitatus EO vapors altered the morphology of P. digitatum hyphae and conidia. The gas-chromatographic analyses of thyme EO indicated that carvacrol was present at 81 to 83%, p-cymene at 4.5 to 5%, gamma-terpinene at 2.6 to 3.3%, caryophyllene at 1.5 to 1.6%, beta-myrcene at 1.6%, and linalool at 1.1 to 1.2%. Carvacrol proved to be the most important fungitoxic compound among the thyme EO constituents, but, unlike thyme EO, it caused alterations to the fruit at the concentration of 75 ppm.

Alternaria↗

Bactericidal activities of plant essential oils and some of their isolated constituents against Campylobacter jejuni, Escherichia coli, Listeria monocytogenes, and Salmonella enterica.

An improved method of sample preparation was used in a microplate assay to evaluate the bactericidal activity levels of 96 essential oils and 23 oil compounds against Campylobacter jejuni, Escherichia coli O157:H7, Listeria monocytogenes, and Salmonella enterica obtained from food and clinical sources. Bactericidal activity (BA50) was defined as the percentage of the sample in the assay mixture that resulted in a 50% decrease in CFU relative to a buffer control. Twenty-seven oils and 12 compounds were active against all four species of bacteria. The oils that were most active against C. jejuni (with BA50 values ranging from 0.003 to 0.009) were marigold, ginger root, jasmine, patchouli, gardenia, cedarwood, carrot seed, celery seed, mugwort, spikenard, and orange bitter oils; those that were most active against E. coli (with BA50 values ranging from 0.046 to 0.14) were oregano, thyme, cinnamon, palmarosa, bay leaf, clove bud, lemon grass, and allspice oils; those that were most active against L monocytogenes (with BA50 values ranging from 0.057 to 0.092) were gardenia, cedarwood, bay leaf, clove bud, oregano, cinnamon, allspice, thyme, and patchouli oils; and those that were most active against S. enterica (with BA50 values ranging from 0.045 to 0.14) were thyme, oregano, cinnamon, clove bud, allspice, bay leaf, palmarosa, and marjoram oils. The oil compounds that were most active against C. jejuni (with BA50 values ranging from 0.003 to 0.034) were cinnamaldehyde, estragole, carvacrol, benzaldehyde, citral, thymol, eugenol, perillaldehyde, carvone R, and geranyl acetate; those that were most active against E. coli (with BA50 values ranging from 0.057 to 0.28) were carvacrol, cinnamaldehyde, thymol, eugenol, salicylaldehyde, geraniol, isoeugenol, citral, perillaldehyde, and estragole; those that were most active against L monocytogenes (with BA50 values ranging from 0.019 to 0.43) were cinnamaldehyde, eugenol, thymol, carvacrol, citral, geraniol, perillaldehyde, carvone S, estragole, and salicylaldehyde; and those that were most active against S. enterica (with BA50 values ranging from 0.034 to 0.21) were thymol, cinnamaldehyde, carvacrol, eugenol, salicylaldehyde, geraniol, isoeugenol, terpineol, perillaldehyde, and estragole. The possible significance of these results with regard to food microbiology is discussed.

Bacteria↗

Radiosensitization of Escherichia coli and Salmonella Typhi in ground beef.

The radiosensitization of two pathogenic bacteria, Escherichia coli and Salmonella Typhi, was evaluated in the presence of thyme and its principal essential oil constituents (carvacrol and thymol) in ground beef. Ground beef was inoculated with E. coli or Salmonella Typhi (10(5) CFU/g), and each compound was added separately at various concentrations (0 to 3.5%, wt/wt). The antimicrobial potential of carvacrol, thymol, and thyme was evaluated in unirradiated meat by determining the MIC in percentage (wt/wt) after 24 h of storage at 4 +/- 1 degree C. Results showed a MIC of 0.88 +/- 0.12%, 1.14 +/- 0.05%, and 2.33 +/- 0.32% for E. coli in the presence of carvacrol, thymol, and thyme, respectively. MICs of 1.15 +/- 0.02%, 1.60 +/- 0.01%, and 2.75 +/- 0.17% were observed for Salmonella Typhi in the presence of the same compounds, respectively. The best antimicrobial compound (i.e., carvacrol) was selected and added to the sterilized ground beef along with ascorbic acid (0.5%, wt/wt) and tetrasodium pyrophosphate (0.1%, wt/wt). Meat samples (10 g) were packed in air and then irradiated in a 60Co irradiator at doses of 0 to 0.7 kGy for the determination of E. coli radiation D10 and 0 to 2.25 kGy for the determination of Salmonella Typhi radiation D10. Addition of carvacrol increased the relative sensitivity of both bacteria 2.2 times. The radiation D10 was reduced from 0.126 +/- 0.0039 to 0.057 +/- 0.0015 kGy for E. coli and from 0.519 +/- 0.0308 to 0.235 +/- 0.0158 kGy for Salmonella Typhi. The addition of tetrasodium pyrophosphate did not affect significantly (P > 0.05) the radiosensitization of either bacterium. However, the presence of ascorbic acid in the media reduced significantly (P < or = 0.05) the radiosensitivity of both bacteria. An additive effect of carvacrol addition and packaging under modified atmosphere conditions (60% O2-30% CO2-10% N2) was also observed on bacterial radiosensitization at 4 degrees C. Compared with the control packed under air, modified atmosphere packaging conditions in the presence of carvacrol and tetrasodium pyrophosphate improved the relative sensitivity of E. coli by 2.7 times and Salmonella Typhi by 9.9 times.

Animals↗

[Microflora of the farming work environment as an occupational risk factor].

The paper presents the results of the studies concerning the air mould fungi concentration in the work environment during grain threshing, flax breaking and thyme cleaning. A high level of fungi was observed in the air at all workplaces with the highest concentrations during grain threshing. Of the total number of 12 farms, in 8 the air mould fungi concentration exceeded the proposed standard of 50,000 CFU/m3. Among the species containing cereals, flax and thyme, mould fungi of Alternaria alternata sp.--an etiologic factor of allergic respiratory diseases--occurred most frequently. During flax breaking, the presence of fungi of Fusarium poae sp., which affect grain husks and cause a great economic loss in agriculture, was observed. Mould fungi of Aspergillus candidus sp. were found during thyme cleaning. These fungi have been reported to be an etiologic factor of organic dust toxic syndrome among secondary school students employed in the grain dust environment polluted with the spores of Aspergillus candidus. The results obtained show that the agricultural work environment is considerably polluted with the spores of mould fungi of allergenic and immunotoxic properties, which cause a high degree of health risk to people employed in agriculture.

Adult↗

Repellent activities of essential oils and monoterpenes against Culex pipiens pallens.

Essential oils of Eulcalyptus globulus, Lavender officinalis, Rosemarinus officinalis, and Thymus vulgaris were examined for their repellent activities against Culex pipiens pallens. All 4 essential oils effectively repelled adult mosquitoes on hairless mice. Essential oil of T. vulgaris (thyme) had potent repellent activity within the tested materials, with a protection rate of 91% at a concentration of 0.05% topical treatment. Thyme essential oil significantly extended the duration of protection until 3 bites by mosquitoes. With gas chromatography-mass spectrometry analysis, thyme essential oil was a rich source of 5 monoterpenes, including in descending order thymol, p-cymene, carvacrol, linalool, and alpha-terpinene. These 5 monoterpenes also were assessed to determine their repellent activities to the mosquitoes. alpha-Terpinene had a potent repellent activity with a protection rate of 97% at a concentration of 0.05% topical treatment. Additionally, carvacrol and thymol showed an equivalent level of repellency. A spray-type solution containing 2% alpha-terpinene was tested for its repellent activity against Cx. pipiens. This solution showed stronger repellent activity than the currently used repellent N,N-diethyl-m-methylbenzamide (deet).

Acyclic Monoterpenes↗

Testing of the palatability of Thymus vulgaris L. and Origanum vulgare L. as flavouring feed additive for weaner pigs on the basis of a choice experiment.

The objective of the study at hand was to investigate within the framework of a pilot project the preference of weaner pigs for either an ad libitum standard feed with thyme or oregano herb as flavouring additive or an ad libitum standard feed without any herbal additive. Thyme or oregano herbs or a combination of both were offered in two different concentrations each (1% and 0.1%) as additive (experimental diets) in standard diet in comparison to the latter without herbal additive (control diet) free of choice. The dosage of the two herbs in terms of total essential oil(s) in the feeds used in the study was 0.02% or 0.002% (v/w), which was equivalent to 1% or 0.1% herbs in the mixture, respectively. A Latin square according to Williams (1949) was used with 6 groups in order to record possible differences in feed intake. All experimental diets aside from that mixed with 0.1% thyme herb were, in comparison to the control diet, significantly less ingested. Where the weanling was given the choice, it did not choose feed with any flavouring additive. Further studies aimed at assessing the use of herbs as aroma additive in the form of a choice experiment are recommended.

Animal Feed↗