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Sustainable management practices are crucial for the longevity of a monoculture vineyard, especially in the context of a changing climate. Therefore, soil management practices in a vineyard (T: tillage, T+FYM: tillage + farmyard manure, G: grass strips, G+NPK1: grass strips + rational rates of NPK, and G+NPK2: grass strips + higher rates of NPK) were tested in a temperate climate of Slovakia (Central Europe) under specific soil conditions (Rendzic Leptosol). We investigated the influence of continuous cropping on soil chemical properties and microbial communities during the dry and warm year of 2022. The results showed that the soil pH was higher by 19%, 21%, 24% and 13% in T, T+FYM, G and G+NPK1, respectively, compared to G+NPK2. The lowest soil organic matter (SOM) content was found in T, and it increased in the following order: T < T+FYM < G+NPK2 < G+NPK1 < G. Similarly, the lowest abundance of soil culturable bacteriota was found in T and it increased in the following order: T < T+FYM = G+NPK2 < G+NPK1< G. Culturable bacteriota was identified using mass spectrometry (MALDI-TOF MS Biotyper). The most numerous species group was Bacillus, followed by Lactobacillus > Staphylococcus > Pseudomonas. The most frequently isolated species were Bacillus megaterium (16.55%), Bacillus cereus (5.80%), Bacillus thuringiensis (4.87%), and Bacillus simplex (4.37%). Positive relationships between SOM and soil culturable bacteriota were found in the G and G+NPK1 treatments. Temperature also affected soil culturable bacteriota in all soil management practices, most significantly in G+NPK1. Overall, the best scenario for the sustainable management of a productive vineyard is the use of grass strips.

Stenotrophomonas maltophilia is the causative agent of nosocomial infections and is characterized by biofilm formation. Primary cell adhesion is crucial in biofilm formation and the type of contact surface has a significant effect. The aim of this work was to assess the antibiofilm activity of Melaleuca leucadendron essential oil. The changes in the biofilm profile of Stenotrophomonas maltophilia were studied using MALDI-TOF MS Biotyper on glass and wooden surfaces. The molecular differences of biofilms in different days were observed as well. The analysis of the mass spectra of S. maltophilia experimental group with Melaleuca leucadendron essential oil showed similarity of the experimental spectra and the control planktonic spectrum on the third day. The results of work proved as such MALDI-TOF MS profiling could be a useful technology for the analysis of biofilm properties.

This study was focused on monitoring of antimicrobial activity of selected medicinal plants: Artemisia vulgaris, Geum urbanum, Euphorbia peplus, Rumex hydrolapathum, Portulaca oleracea, Geranium pratense, Polygonum aviculare. The selected medicinal plants were evaluated for antimicrobial activity with disc diffusion method. Ethanolic extracts against 3 Gram-positive (G+) bacteria (Staphylococcus aureus, Enterococcus faecalis, Bacillus subtilis), 3 Gram-negative (G-) bacteria (Salmonella enterica, Pseudomonas aeruginosa, Yersinia enterocolitica) and 3 yeasts (Candida tropicalis, Candida krusei, Candida glabrata, Candida albicans) were used as model microorganisms to determine antimicrobial activity. The Portulaca oleracea extract showed the largest zone of inhibition against Staphylococcus aureus, Pseudomonas aeruginosa and Yersinia enterocolitica. Artemisia vulgaris extract formed the largest zone of inhibition against Bacillus subtilis, Enterococcus faecalis and one yeast Candida krusei. The extract from Geum urbanum and Euphorbia peplus did not create the maximum inhibition zone against any of the microorganisms that were tested.

Slovak smoked cow cheese “Parenica” is a traditional dairy product with a protected geographical indication. An amount of 96 samples were studied in the present study. The samples were examined for coliforms (VRBL medium at 37 °C for 24-48 h), for lactic acid bacteria (on MRS media at 30 °C for 48-72 h), microscopic filamentous fungi (MEA at 25 °C for 5 days) and total microbial counts (PCA at 30 °C for 48-72 h). Individual species of microorganisms isolated from smoked cheese “parenica” were identified with MALDI-TOF MS Biotyper. Totally, 41 species of microorganisms were identified. The most abundant species were Lactobacillus fermentum, Lactococcus lactis, Enterococcus faecium, and Escherichia coli. Microscopic filamentous fungi were represented by the genus Rhizopus spp. and yeasts by species of Yarrowia lipolytica and Kluyveromyces lactis. Of the total number of isolates 47.66% were lactic acid bacteria, 27.84% coliform bacteria, 18.66% yeasts and 5.85% of microscopic filamentous fungi. The occurrence of microorganisms increased in the summer then the highest values ​​of coliform bacteria were detected 1.74 log cfu/g. The lactic acid bacteria counts found in summer were 2.19 log cfu/g, and the highest counts were observed ​​in December - 2.66 log cfu/g.

The aim of the study was to determine antimicrobial and antioxidant activity of plant extracts against pathogenic microorganisms in vitro. Extracts of black elder (Sambucus nigra L.), stinging nettle (Urtica dioica L.), marigold (Calendula officinalis L.) and ribwort plantain (Plantago lanceolata L.) were used in experiments and tested against gram-negative bacteria: Pseudomonas aeruginosa CCM 1959, Salmonella enterica subsp. enterica CCM 3807, Yersinia enterocolitica CCM 5671, gram-positive bacteria: Enterococcus faecalis CCM 4224, Staphylococcus aureus subsp. aureus CCM 4223, Streptococcus pneumoniae CCM 4501, and against yeasts: Candida albicans CCM 8186, Candida krusei CCM 8271, Candida tropicalis CCM 8223. The evaluation of antimicrobial effects was performed with disc diffusion method and the minimum inhibitory concentration (MIC) method. Determination of antioxidant activity was performed using the spectrophotometric method. Some species of selected plants were extremely effective against individual pathogenic microorganisms. Using the disc diffusion method, the best antimicrobial activity was reported for the extract from black elder (Sambucus nigra L.) and stinging nettle (Urtica dioica L.). The best antimicrobial activity by the MIC method was found in the extract of ribwort plantain (Plantago lanceolata L.) which was effective against all gram-negative bacteria. The highest antioxidant activity was determined in the extract from black elder (Sambucus nigra L.).

The analysis was aimed to evaluate the antimicrobial activity of the essential oil Origanum vulgare against various gram-positive and gram-negative bacteria and yeast. To test its suitability in the vapor phase for the elimination of biofilm-forming bacteria on fruits and vegetables. To evaluate its potential for use in the storage of vegetables and fruits. The tested essential oil Origanum vulgare showed strong antimicrobial activity against various types of microorganisms. Due to the high antimicrobial activity against diverse group of microorganisms, it could also be a suitable option for the post-harvest treatment of crops in the future. In evaluating the inhibitory activity in the vapor phase, an effect on the biofilm-forming bacteria S. maltophilia and B. subtilis was demonstrated. Against S. maltophilia, the highest efficacy was found at a concentration of 500 µL/L by 91.27% inhibition of bacteria on potatoes. Against B. subtilis, the most effective concentration was 250 µL/L by 63.24 % of bacterial inhibition on carrots. Relatively stable growth inhibition was found in the apple sample at all concentrations tested. Due to the vaporous application, it would be possible to use lower concentrations of essential oils to achieve the antimicrobial activity. The impact on the sensory properties of food would be reduced.

Essential oils are applied for many purposes in pharmaceutical, cosmetic, agriculture, and food industries for their beneficial properties. Due to their bioactive compounds essential oils have an anti-inflammatory, analgetic, cardiovascular or anticancer potential. They can be used as an antioxidant and inhibitor of pathogenic microorganisms in order to improve food quality and extend the shelf life of the food products. The aim of the study was to characterise antioxidant and antimicrobial activity of Citrus aurantium var. bergamia essential oil from Slovak company. Antioxidant capacity of Citrus aurantium var. bergamia essential oil was determined by DPPH radical scavenging method at 54.11%. Antimicrobial activity of Bergamot essential oil was the most effective against yeasts C. krusei and C. tropicalis with inhibition zones 12.67 and 9.33 mm, respectively. The bacteria P. aeruginosa and B. subtilis were also vulnerable where inhibition zones ranged 8.67 and 8.33 mm, respectively.

The aim of the work was to explore the antioxidant potential and antibiofilm activity of the Rosmarinus officinalis essential oil. The DPPH method was used to determine the antioxidant activity. The agar microdilution method was used to determine the minimum biofilm inhibiting concentration (MBIC). The MALDI-TOF MS Biotyper was used to evaluate the antibiofilm activity on the wood and glass surface. Vapor phase antimicrobial analysis was used to determine the effect on the food model. The antioxidant activity was 28.76 % ± 2.68 %. The MBIC for Stenotrophomonas maltophilia was 25 µL.mL-1 and for Bacillus subtilis 12.5 µL.mL-1. Analysis of the mass spectra of S. maltophilia revealed an inhibitory effect from the 5th, which persisted until the end of the experiment. Analysis of the mass spectra of B. subtilis showed an inhibitory effect from the 7th of the experiment. The experiments showed an effect on both tested surfaces. The food model showed a more pronounced effect of the Rosmarinus officinalis essential oil against B. subtilis. We assume that the effect of the essential oil is to disrupt the polysaccharide structure of the biofilm and consequently reduce the resistance of the biofilm. We have established that MALDI-TOF MS Biotyper is a suitable tool for evaluating changes in biofilm structure and could find more significant application for the study of biofilms in food and clinical practice.

The aim of this study was to compare the effectiveness of contact and steam application of essential oils Cinnamomum cassia and Cananga odorata. Using the disk diffusion method, we found that Cinnamomum cassia essential oil achieved good effects against gram-positive, gram-negative bacteria and yeasts in contact application. Very weak efficacy was found against filamentous microscopic fungi. Cananga odorata essential oil showed very weak antibacterial effects after contact application. Inhibition of yeast and filamentous microscopic fungi was weak to moderate. In the vapor phase, C. cassia essential oil achieved very good antibacterial effects and its effect on the inhibition of filamentous microscopic fungi was significantly increased. C. odorata essential oil showed significantly better inhibitory effects against gram-negative and gram-positive bacteria. Its effectiveness against filamentous microscopic fungi was higher than with contact application. These findings suggest that essential oils with a higher proportion of volatile compounds may increase their effectiveness when vapor is applied. Although there is still no standard methodology for determining the activity of essential oils in the vapor phase, results reported thus far are encouraging and suggest possible applications in food preservation. With higher efficiency, lower amounts of essential oils are sufficient, which reduces the impact on sensory properties.

Essential oils are natural, aromatic and volatile liquids, which are frequently obtained by steam or water distillation from plants. In general, they have a pleasant odor and their proven antimicrobial, antiviral, antifungal, antioxidant, antifungal, insecticidal and antiparasitic properties have been known for several years. The aim of this work was to monitor antimicrobial activity against pathogenic microorganisms using two methods. The antimicrobial activity of essential oils was determined using the disk diffusion method and the broth dilution method. We found that wild thyme and peppermint essential oils were the most effective against the gram-negative bacterium Pseudomonas aeruginosa CCM 3955 in both cases with size of an inhibition zone 20.66 mm measured by disk diffusion method. Coriander essential oil had the best antimicrobial activity against all tested pathogenic microorganisms in the range of concentrations from 0.75 µg.ml-1 to 13.35 µg.ml-1 with broth dilution method.

Poultry meat is currently considered as a dietetic food due to its valuable biological and nutritional characteristics. This poultry meat is high in protein, essential amino acids, minerals and is low in fat. Meat is for its optimal composition and high-water activity very suitable breeding ground for undesirable microorganisms that cause microbial spoilage of meat. To prolong the shelf life of meat and preserve its quality and hygienic properties various forms of packaging are used. The aim of our work was to investigate the antimicrobial activity of essential oil from coriander in combination with vacuum packaging. Samples were collected from sous vide chicken breast meat, prepared in vacuum. Listeria monocytogenes and coriander essential oil were applied on the chicken breast meat. After application, the samples were prepared by sous vide cooking at four different temperatures (50 °C, 55 °C, 60 °C, and 65 °C) during different time of intervals (5; 15; 30; and 60 min). The primary objective was to isolate and analyze the bacteria by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) Biotyper and with mass spectrometry (MS). Gram-positive and Gram-negative bacteria were identified. Most frequent type of bacteria isolated from samples were Gram-negative bacteria. The presence of the dominant species Listeria monocytogenes varied depending on temperature and time.

The aim of the present study was to evaluate the effect of lupine flour on selected parameters of novel bakery products. Different proportions of lupine flour - from 25% to 100% - were added to the baked biscuits; wheat flour biscuits were prepared as the control sample. Increasing lupine content has positively affected mineral concentrations and sensory properties. After 4 days of storage, the lupine biscuit samples showed no significant differences in their water activity values when compared with each other. Compared with the control sample, the concentration of Ca was considerably increased by 1.2% in the biscuits with 25% lupine flour addition, which represents 5.8% of the recommended daily intake of Ca contained in 100 g of biscuits. The biscuits containing 25% of lupine flour showed no significant difference in colour compared to the control sample. The intensity of the sensory properties of the biscuits increased by adding more lupine flour; all the samples of lupine biscuits were acceptable to the evaluators. Based on the results, 25% of lupine flour addition may be considered the most appropriate.

Bryndza cheese includes several predominant lactic acid bacteria. The aim of our study was the antagonistic effect of lactic acid bacteria supernatant isolated from ewes´ cheese bryndza against ten Gram-positive and Gram-negative bacteria. Isolated strains of bacteria were obtained from bryndza which were produced in five different regions of Slovakia. Isolated strains of lactic acid bacteria were identified with mass spectrometry MALDI-TOF MS Biotyper. A total of one hundred and thirty lactic bacteria include Enterococcus faecalis, Enterococcus faecium, Enterococcus hirae, Lactobacillus brevis, Lactobacillus harbinensis, Lactobacillus johnsonii, Lactobacillus plantarum, Lactobacillus paracasei ssp. paracasei, Lactobacillus paraplantarum, Lactobacillus suebicus, Lactococcus lactis ssp. lactis, Lactococcus lactis, and Pediococcus acidilactici were tested in this study against Gram-negative bacteria: Escherichia coli CCM 3988, Klebsiella pneumoniae CCM 2318, Salmonella enterica subsp. enterica CCM 3807, Shigella sonnei CCM 1373, Yersinia enterocolitica CCM 5671 and Gram-positive bacteria: Bacillus thuringiensis CCM 19, Enterococcus faecalis CCM 4224, Listeria monocytogenes CCM 4699, Staphylococcus aureus subsp. aureus CCM 2461, Streptococcus pneumonia CCM 4501 with agar diffusion method. Lactic acid bacteria showed activity 92% against Yersinia enterocolitica, 91% against Klebsiella pneumoniae, 88% against Escherichia coli, 84% against Listeria monocytogenes. The most effective bacteria against Gram-positive and Gram-negative bacteria tested was Lactobacillus paracasei ssp. paracasei.

Work aimed to investigate the antimicrobial activity of medicinal plants against selected species of food industry pathogens in vitro conditions. The detection of antibacterial properties was examined by the disc diffusion method and the method of the minimum inhibitory concentrations (MIC). The cultivation of microorganisms after the 24 h was performed by disc diffusion method. Petri dishes have grown at 37 °C in which the Mueller - Hinton agar and application it to the sterile paper disc impregnated with the extract. The thickness of the resulting inhibition zone was measured with a ruler after completion of the culture. After the preparation of bacteria and extracts of certain concentrations of a subsequently added to wells microplates we use the method of the minimum inhibitory concentration (MIC) which was conducted out as the second measurement, and we took the readings absorbance spectrophotometer at 570 nm using the Glomax plate spectrophotometer. We found out, that Equisetum arvense demonstrated the largest zones of inhibition to the tested Gram-positive and Gram-negative bacteria. The greatest antimicrobial activity achieved Equisetum arvense, Urtica dioica, and Taraxacum officinale against Salmonella enterica subsp. enterica CCM 3807 and Yersinia enterocolitica CCM 5671. Equisetum arvense and Taraxacum officinale was the most effective against Escherichia coli CCM 2024 and the least effective were Tussilago farfara and Mentha piperita with using the method of minimum inhibitory concentrations.

Boswellia carterii, known as frankincense, is a fragrant medicinal plant. The essential oil from this plant is often used in traditional medicine or aromatherapy. Due to its positive properties, it has potential applications as an antimicrobial agent in medicine and the food industry. The aim of this study was to evaluate the antimicrobial, anti-insect, and antioxidant activities of frankincense essential oil (FEO). The composition of volatile compounds was determined by GC/MS, and the main components were found to be α-pinene (37.0%), α-limonene (19.8%), and p-cymene (6.3%). The antioxidant activity was evaluated with DPPH and ABTS methods with the resulting inhibition of 73.88 ± 0.35% of DPPH radical (6.27 ± 0.17 TEAC) and 97.09 ± 0.48% of ABTS radical cation (5.21 ± 0.07 TEAC). The antimicrobial activity was the strongest against Candida species with inhibition zones in the range of 38.00–44.00 mm and MIC 50 and MIC 90 values of 11.72 and 12.58 μL/mL, respectively. The inhibition activity of the vapor phase was the highest against G+ and G− bacteria growing on a carrot with inhibition ranging from 65.14 to 93.67%. The anti-insect activity against O. lavaterae was determined as 100% at 100% concentration and 50% at 25% concentration. The degradation of biofilm was tested with MALDI-TOF MS, and changes in the protein profile were observed.

Honey contains compounds with antioxidant and antibacterial capacities, such as phenolic compounds and carotenoids. The current analysis evaluates the antioxidant and antibacterial activity of 100 honey samples from beekeepers from Slovakia and commercially purchased ones. Honey samples were diluted to 50%, 25%, 12.5%, and 6.25% concentrations. The antimicrobial activity of honey samples was evaluated against three Gram-positive, three Gram-negative bacteria, and four Candida spp. by well diffusion method. The highest antimicrobial effect of all honey concentrations was expressed as the size of the inhibition zone and was found against Pseudomonas aeruginosa among Gram-negative bacteria, Bacillus subtilis among Gram-positive bacteria, and Candida tropicalis among yeasts. Antibiotics used in the study showed the highest antimicrobial effect compared to all concentrations of honey samples. Slovakian honey from beekeepers and commercial honey samples from the Slovak market showed variable inhibitory effectiveness against microorganisms. The honey concentration of 50% was found the most effective. Lower concentrations of honey exhibited no effect against yeasts. The best antioxidant activity was found in a sample of buckwheat honey yielding 70.83% of DPPH inhibition and 2373.85 μg/g TEAC. Overall, better antioxidant activity was evaluated in honeydew honey.

The aim of the research was to determine the antioxidant and antimicrobial activity, determination of chemical elements and heavy metals in seaweed extracts of wakame, arame, dulse, laminaria, kombu, and hijiki. Antioxidant activity was determined by DPPH method and the activity ranged from 0.00 to 2641.34 TEAC. The highest antioxidant activity was observed in kombu (2641.34 TEAC) and arame (2457.5 TEAC). Antimicrobial activity was analyzed by disk diffusion method and MIC method. Three G+ bacteria (Staphylococcus aureus, Enterococcus faecalis, Bacillus subtilis), three G- bacteria (Salmonella enterica, Pseudomonas aeruginosa, Yersinia enterocolitica), and four yeasts (Candida tropicalis, C. krusei, C. glabrata, C. albicans) were used as model organisms. The size of inhibition zones ranged from 0.00 to 8.67 mm. The minimum inhibitory concentrations of the selected seaweeds ranged from MIC50 98.46 (MIC90 100.25) to MIC50 3.43 µL/mL (MIC90 5.26 µL/mL). The content of selected elements was determined in seaweed samples by ICP-OES. The chemical composition of the algae showed differences between species and the presence of heavy metals. Arsenic, cadmium, and aluminum were confirmed. All seaweed samples contained arsenic ranging from 6.6546 to 76.48 mg/kg. Further investigation of seaweeds is needed to identify the active substances present in the algae that are responsible for antioxidant and antimicrobial activity. This study was carried out to evaluate the antimicrobial and antioxidant activity of extracts from five commonly consumed seaweeds for their ability to inhibit selected microorganisms and to determine the health risk due to heavy metals content. Our study contributes to the evidence that seaweeds have antimicrobial and antioxidant activity and seaweed extracts have for pharmacological applications.

The essential oil from Litsea cubeba (LCEO) has good antioxidant, antimicrobial, anti-insect properties, which gives it the potential for use as a natural additive to food resources and food products in order to prevent spoilage and extend shelf life. In this study the biological activity related to food preservation was observed. The main volatile organic compounds were geranial (39.4%), neral (29.5%), and limonene (14.3%). Antioxidant activity was 30.9%, which was equal to 167.94 µg of Trolox per mL of sample. Antimicrobial activity showed the strongest inhibition against Serratia marcescens by disk diffusion method and minimum inhibitory concentrations MIC 50 and MIC 90 were the lowest for Micrococcus luteus with values 1.46 and 3.52 µL/mL, respectively. Antimicrobial activity of the LCEO vapor phase showed strong inhibition of microorganisms on apples, pears, potatoes, and kohlrabies. Over 50% of gram-positive and gram-negative bacteria and yeasts were inhibited by a concentration of 500 µL/mL. The inhibition of microorganisms was concentration dependent. Anti-insect activity was also strong, with 100% lethality of Pyrrhocoris apterus at a concentration of 25%. These results suggest that LCEO could be potentially used as a food preservative.

Basil (Ocimum basilicum) is a commonly used herb; it also contains essential oils and other valuable compounds. The basil oil obtained has a pleasant aroma, but also a broad spectrum of biological activity. This work reports on the chemical composition, antioxidant, antimicrobial and anti-insect activity in vitro and in situ of Ocimum basilicum essential oil (OBEO) obtained by steam distillation of fresh flowering plants. Gas chromatography–mass spectrometry, DPPH, agar and disc diffusion and vapor phase methods were used to analyze the OBEO properties. The analysis of the chemical composition of OBEO showed that its main components were methyl chavicol (88.6%), 1,8-cineole (4.2%) and α-trans-bergamotene (1.7%). A strong antioxidant effect was demonstrated at the level of 77.3%. The analysis of antimicrobial properties showed that OBEO exerts variable strength of inhibiting activity against various groups of microorganisms. The growth inhibition zones ranged from 9.67 to 15.33 mm in Gram-positive (G+) and Gram-negative (G−) bacteria and from 5.33 to 7.33 mm in yeast. The lowest measured minimal inhibition concentration (MIC) was 3.21 µL/mL against Gram-negative Azotobacter chrococcum and Gram-positive Micrococcus luteus. The antimicrobial activity of in situ vapor phase of OBEO was also confirmed on apples, pears, potatoes and kohlrabi. The highest insecticidal activity against Pyrrhocorisapterus, observed at the concentration of 100%, caused the death of 80% of individuals. Due to its broad spectrum of activity, OBEO seems an ideal candidate for preserving fruit and vegetables.

The primary objective of the study was to evaluate the biological activity of Citrus aurantifolia essential oil (CAEO) with emphasis on antioxidant, antimicrobial, and insecticidal activity, chemical composition, and the antimicrobial effect of its vapor phase in situ on various food models. We determined the main volatile components of CAEO as α-phellandrene (48.5%) and p-cymene (16.5%). The antioxidant activity was high and reached 74.5 ± 0.5%, which corresponds to 442 ± 2.3 TEAC. The antimicrobial activity in the contact phase was most pronounced against Gram-negative bacteria, with inhibition zones of 12.66–15.33 mm and a minimal inhibition concentration of 2.36–8.26 µL/mL. The antimicrobial activity of the CAEO vapor phase was high at the highest concentration tested (500 µL/mL), but the inhibitory effect was seen at all concentrations tested. The effect was observed on all types of microorganisms and all types of model foods. Based on the findings, CAEO could find use in storing and extending the shelf life of agricultural products. Insecticidal activity reached 10–90% depending on the concentration used. The significant insecticidal effect provides the possibility of using CAEO as a natural insecticidal, larvicidal, or repellent preparation.

This study aimed to analyze the biological activity of the essential oil Pogostemon cablin (PCEO) to determine the antioxidant, antimicrobial, antibiofilm, insecticidal activity, and chemical composition of the essential oil. We analyzed the structure of biofilms on various surfaces using the MALDI-TOF MS Biotyper and evaluated the antimicrobial effect of the vapor phase of the essential oil in a food model. We determined the main volatile components of PCEO as patchouli alcohol 31.0%, α-bulnesene 21.3%, and α-guaiene 14.3%. The free radical scavenging activity was high and reached 71.4 ± 0.9%, corresponding to 732 ± 8.1 TEAC. The antimicrobial activity against bacteria was weak to moderate. We recorded strong activity against yeast. The antifungal activity was very weak in the contact application. Biofilm-producing bacteria were moderately inhibited by PCEO. The change in biofilm structure due to essential oil was demonstrated by MALDI-TOF MS Biotyper analysis. Vapor phase application in a food model showed relatively strong effects against bacteria and significantly higher antifungal efficacy. The insecticidal activity was observed only at higher concentrations of essential oil. Based on the findings, PCEO can be used in the food industry as an antifungal substance in extending the shelf life of bakery products and as protection in the storage of root vegetables.

The essential oil of Melaleuca alternifolia, commonly known as tea tree oil, has many beneficial properties due to its bioactive compounds. The aim of this research was to characterize the tea tree essential oil (TTEO) from Slovakia and its biological properties, which are specific to the chemical composition of essential oil. Gas chromatography/mass spectroscopy revealed that terpinen-4-ol was dominant with a content of 40.3%. γ-Terpinene, 1,8-cineole, and p-cymene were identified in contents of 11.7%, 7.0%, and 6.2%, respectively. Antioxidant activity was determined at 41.6% radical inhibition, which was equivalent to 447 μg Trolox to 1 mL sample. Antimicrobial activity was observed by the disk diffusion method against Gram-positive (G+), Gram-negative (G−) bacteria and against yeasts, where the best antimicrobial activity was against Enterococcus faecalis and Candida albicans with an inhibition zone of 10.67 mm. The minimum inhibitory concentration showed better susceptibility by G+ and G− planktonic cells, while yeast species and biofilm-forming bacteria strains were more resistant. Antibiofilm activity was observed against Pseudomonas fluorescens and Salmonella enterica by MALDI-TOF, where degradation of the protein spectra after the addition of essential oil was obtained. Good biological properties of tea tree essential oil allow its use in the food industry or in medicine as an antioxidant and antimicrobial agent.

Antimicrobial in vitro and in situ efficacies of Cymbopogon citratus essential oil (lemongrass, LGEO) against 17 spoilage microorganisms (bacteria, yeasts and fungi) were evaluated. Additionally, its chemical composition, and antioxidant and antibiofilm activities were investigated. The LGEO exhibited a strong antioxidant activity (84.0 ± 0.1%), and its main constituents were citral (61.5%), geraniol (6.6%) and 1,8-cineole (6.4%). An in vitro antimicrobial evaluation revealed the lowest inhibition zone (1.00 ± 0.00 mm) in Pseudomonas fluorescens, and the highest inhibition zone (18.00 ± 2.46 mm) in Candida krusei. The values for the minimal inhibitory concentration were determined to be the lowest for Salmonella enteritidis and the highest for C. albicans. Furthermore, the concentration of ≥250 µL/L of LGEO suppressed the growth of Penicillium aurantiogriseum, Penicillium expansum, Penicillium chrysogenum and Penicillium italicum. The changes in the molecular structure of the biofilms produced by Pseudomonas fluorescens and Salmonella enteritidis, after their treatment with LGEO, confirmed its action on both biofilm-forming bacteria. Moreover, an in situ antimicrobial activity evaluation displayed the most effective inhibitory effectiveness of LGEO against Micrococcus luteus, Serratia marcescens (250 µL/L) and Penicillium expansum (125, 250 and 500 µL/L) growing on a carrot. Our results suggest that LGEO, as a promising natural antimicrobial agent, can be applied in the innovative packaging of bakery products and different types of vegetables, which combines commonly used packing materials with the addition of LGEO.

The essential oil of Syzygium (S.) aromaticum (CEO) is known for its good biological activity. The aim of the research was to evaluate in vitro and in situ antimicrobial and antibiofilm activity of the essential oil produced in Slovakia. The main components of CEO were eugenol 82.4% and (E)-caryophyllene 14.0%. The antimicrobial activity was either weak or very strong with inhibition zones ranging from 4.67 to 15.78 mm in gram-positive and gram-negative bacteria and from 8.22 to 18.56 mm in yeasts and fungi. Among the tested bacteria and fungi, the lowest values of MIC were determined for Staphylococcus (S.) aureus and Penicillium (P.) expansum, respectively. The vapor phase of CEO inhibited the growth of the microscopic filamentous fungi of the genus Penicillium when tested in situ on bread. The strongest effect of mycelia inhibition in a bread model was observed against P. expansum at concentrations of 250 and 500 μL/mL. The best antimicrobial activity of CEO in the carrot model was found against P. chrysosenum. Differences between the mass spectra of Bacillus (B.) subtilis biofilms on the tested surfaces (wood, glass) and the control sample were noted from the seventh day of culture. There were some changes in mass spectra of Stenotrophomonas (S.) maltophilia, which were observed in both experimental groups from the fifth day of culture. These findings confirmed the impact of CEO on the protein structure of older biofilms. The findings indicate that, besides being safe and sensorially attractive, S. aromaticum has antimicrobial activity, which makes it a potential substitute for chemical food preservatives.

Thymus vulgaris essential oil has potential good biological activity. The aim of the research was to evaluate the biological activity of the T. vulgaris essential oil from the Slovak company. The main components of T. vulgaris essential oil were thymol (48.1%), p-cymene (11.7%), 1,8-cineole (6.7), γ-terpinene (6.1%), and carvacrol (5.5%). The antioxidant activity was 85.2 ± 0.2%, which corresponds to 479.34 ± 1.1 TEAC. The antimicrobial activity was moderate or very strong with inhibition zones from 9.89 to 22.44 mm. The lowest values of MIC were determined against B. subtilis, E. faecalis, and S. aureus. In situ antifungal analysis on bread shows that the vapor phase of T. vulgaris essential oil can inhibit the growth of the microscopic filamentous fungi of the genus Penicillium. The antimicrobial activity against S. marcescens showed 46.78–87.80% inhibition at concentrations 62.5–500 µL/mL. The MALDI TOF MS analyses suggest changes in the protein profile of biofilm forming bacteria P. fluorescens and S. enteritidis after the fifth and the ninth day, respectively. Due to the properties of the T. vulgaris essential oil, it can be used in the food industry as a natural supplement to extend the shelf life of the foods.

The aim of this study was to analyze the chemical composition and biological and antibiofilm activity of the essential oil (EO) of Thymus serpyllum with the use of a MALDI-TOF MS Biotyper. The main compounds of the EO were thymol, 18.8%; carvacrol, 17.4%; o-cymene, 15.4%; and geraniol, 10.7%. It was found that free-radical scavenging activity was high. The highest antimicrobial activity was observed against Pseudomonas aeruginosa, Salmonella enteritidis, and biofilm-forming bacteria. The changes in the biofilm structure after T. serpyllum EO application confirmed the inhibitory action and the most pronounced effect was observed on Bacillus subtilis biofilm. The antifungal activity of the vapor phase was the most effective against Penicillium crustosum. T. serpyllum should be a suitable alternative to synthetic antioxidants as well as antimicrobials. The EO of T. serpyllum can be used in the vapor phase in the storage of root vegetables as well as a growth inhibitor of Penicillium on bread.

The main aim of the study was to investigate the chemical composition, antioxidant, antimicrobial, and antibiofilm activity of Citrus aurantium essential oil (CAEO). The biofilm profile of Stenotrophonomonas maltophilia and Bacillus subtilis were assessed using the mass spectrometry MALDI-TOF MS Biotyper and the antibiofilm activity of Citrus aurantium (CAEO) was studied on wood and glass surfaces. A semi-quantitative composition using a modified version was applied for the CAEO characterization. The antioxidant activity of CAEO was determined using the DPPH method. The antimicrobial activity was analyzed by disc diffusion for two biofilm producing bacteria, while the vapor phase was used for three penicillia. The antibiofilm activity was observed with the agar microdilution method. The molecular differences of biofilm formation on different days were analyzed, and the genetic similarity was studied with dendrograms constructed from MSP spectra to illustrate the grouping profiles of S. maltophilia and B. subtilis. A differentiated branch was obtained for early growth variants of S. maltophilia for planktonic cells and all experimental groups. The time span can be reported for the grouping pattern of B. subtilis preferentially when comparing to the media matrix, but without clear differences among variants. Furthermore, the minimum inhibitory doses of the CAEO were investigated against microscopic fungi. The results showed that CAEO was most active against Penicillium crustosum, in the vapor phase, on bread and carrot in situ.

The aim of this study was to assess the chemical composition, antioxidant, antimicrobial and antibiofilm activity of the Coriandrum sativum essential oil. Changes in the biofilm profile of Stenotropomonas maltophilia and Bacillus subtilis were studied using MALDI-TOF MS Biotyper on glass and wooden surfaces. The molecular differences of biofilms in different days were observed as well. The major volatile compounds of the coriander essential oil in the present study were β-linalool 66.07%. Coriander essential oil radical scavenging activity was 51.05% of inhibition. Coriander essential oil expressed the strongest antibacterial activity against B. subtilis followed by S. maltophilia and Penicillium expansum. The strongest antibiofilm activity of the coriander essential oil was found against S. maltophilia. A clearly differentiated branch was obtained for early growth variants of S. maltophilia in case of planktonic cells and all experimental groups and time span can be reported for the grouping pattern of B. subtilis preferentially when comparing to the media matrix, but without clear differences among variants. The results indicate that coriander was effective against the tested Penicillium expansum in the vapor phase after 14 days with MID50 367.19 and MID90 445.92 µL/L of air.