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Cryptosporidium spp. and Giardia duodenalis are zoonotic food- and water-borne protozoa of veterinary importance. They are one of the main causes of diarrhea in domestic dogs (Canis familiaris). Wild canids, such as red foxes (Vulpes vulpes) and raccoon dogs (Nyctereutes procyonoides), can act as natural reservoirs for these parasites. The aim of this study was to estimate the prevalence of these pathogens and analyze possible factors that may affect the infection in wild and domestic canids. A total of 373 domestic dog, 219 red fox, and 78 raccoon dog fecal samples were collected and tested for Cryptosporidium spp. and G. duodenalis presence with direct immunofluorescent staining. The dog owners filled a questionnaire on the dog’s habits and lifestyle to identify and analyze potential factors that may affect the occurrence of these parasites in dogs. Cryptosporidium spp. were found in 16.3%, 28.3%, and 28.2% and G. duodenalis in 0.7%, 27.4%, and 30.8% of the examined dogs, red foxes, and raccoon dogs, respectively. The highest prevalence was observed in puppies—15.4% and 18.5% for Cryptosporidium spp. and G. duodenalis, respectively. In all three canid species, infection with Cryptosporidium increases the risk of co-infection with Giardia and vice versa.

The growing emphasis on food safety and healthier lifestyles, driven by industrial expansion and scientific priorities, has highlighted the necessity of managing harmful microorganisms to guarantee food quality. A significant challenge in this domain is the control of pathogens that are capable of forming biofilms, entering a sessile state that enhances their resistance to broad-spectrum antibiotics. Essential oils, renowned for their antibacterial properties, present a promising natural alternative for food preservation. In this study, we analyzed the chemical composition of Santalum album essential oil (SAEO) using GC-MS, identifying (Z)-α-santalol (57.1%) as the primary constituent. Antimicrobial activity was confirmed through disc diffusion and minimum inhibitory concentration (MIC) assays against Gram-positive and Gram-negative bacteria and yeast from the genus Candida. Additionally, in situ experiments demonstrated that vapor-phase SAEO effectively inhibited Serratia marcescens on the food model, supporting its potential as a natural preservative. MBIC assays, crystal violet staining, and MALDI-TOF MS analysis on S. enterica biofilms were used to further evaluate the antibiofilm effects of SAEO. The crystal violet assay revealed a strong antibiofilm effect, while the MALDI-TOF MS analysis showed changes in the bacterial protein profiles on both glass and plastic surfaces. SAEO also showed significant anti-Salmonella activity on vacuum-packed carrot slices. SAEO outperformed the control samples. The insecticidal activity against Megabruchidius dorsalis was also studied in this work, and the best insecticidal activity was found at the highest concentrations. These findings indicate that SAEO could serve as a valuable component in food preservation, with notable antibacterial and antibiofilm benefits.

Rosa damascena is mostly grown for its usage in the food, medical, and perfume industries, while it is also used as an attractive plant in parks, gardens, and homes. The use of R. damascena essential oil may yield new results in relation to the antimicrobial activity of essential oils and their use mainly in extending the shelf life of foods. This study investigates the chemical composition and antimicrobial properties of Rosa damascena essential oil (RDEO) using gas chromatography–mass spectrometry (GC-MS) and various bioassays to explore its potential applications in food preservation and microorganism growth control. The GC-MS analysis revealed that RDEO is predominantly composed of phenylethyl alcohol (70%), which is known for its antimicrobial and aromatic properties. Additionally, other significant constituents were identified, including nerol, citronellol, and geraniol, which may contribute to the EOs overall bioactivity. The antimicrobial activity was assessed through the minimal inhibition concentration against five Candida yeast strains, four Gram-positive, and four Gram-negative bacteria, including biofilm-forming Salmonella enterica. Determination of minimum inhibitory concentrations (MIC) revealed the strongest effects of RDEO’s on Gram-negative species, with MIC50 values as low as 0.250 mg/mL for S. enterica. Moreover, an in situ assessment utilizing fruit and vegetable models demonstrated that the vapor phase of RDEO significantly suppressed microbial growth, with the most substantial reductions observed on kiwi and banana models. As a result of our study, the antimicrobial effect of RDEO on the microbiota of sous vide processed eggplant was detected, as well as an inhibitory effect on S. enterica during storage. The insecticidal activity against Megabruchidius dorsalis Fahreus, 1839, was also studied in this work and the best insecticidal activity was found at the highest concentrations. These results suggest that RDEO has the potential to serve as a natural antimicrobial agent in food preservation and safety applications, providing an alternative to synthetic preservatives.

Antimicrobial resistance (AMR) is an emerging public health threat and is one of the One Health priorities for humans, animals, and environmental health. Red foxes (Vulpes vulpes) are a widespread predator species with great ecological significance, and they may serve as a sentinel of antimicrobial resistance in the general environment. The present study was carried out to detect antimicrobial resistance, antimicrobial resistance genes, and genetic diversity in faecal isolates of red foxes (Vulpes vulpes). In total, 34 Enterococcus isolates, including E. faecium (n = 17), E. faecalis (n = 12), E. durans (n = 3), and E. hirae (n = 2), were isolated. Antimicrobial resistance to 12 antimicrobial agents was detected with EUVENC panels using the minimum inhibitory concentration (MIC). The presence of antimicrobial resistance genes (ARGs) was determined using whole-genome sequencing (WGS). Resistance to tetracycline (6/34), erythromycin (3/34), ciprofloxacin (2/34), tigecycline (2/34), and daptomycin (2/34) was identified in 44% (15/34) of Enterococcus isolates, while all the isolates were found to be susceptible to ampicillin, chloramphenicol, gentamicin, linezolid, teicoplanin, and vancomycin. No multi-resistant Enterococcus spp. were detected. A total of 12 ARGs were identified in Enterococcus spp., with the presence of at least 1 ARG in every isolate. The identified ARGs encoded resistance to aminoglycosides (aac(6′)-I, ant(6)-Ia, aac(6′)-Iih and spw), tetracyclines (tet(M), tet(L) and tet(S)), and macrolide–lincosamide–streptogramin AB (lnu(B,G), lsa(A,E), and msr(C)), and their presence was associated with phenotypical resistance. Core genome multilocus sequence typing (cgMLST) revealed the high diversity of E. faecalis and E. faecium isolates, even within the same geographical area. The distribution of resistant Enterococcus spp. in wild foxes in Latvia highlights the importance of a One Health approach in tackling AMR.

Listeria innocua is considered as non-pathogenic bacteria living in an environment although several cases of immunocompromised humans and ruminant listeriosis infections have been reported. Previously, L. innocua was identified as a potential pathogen and virulence in association with L. monocytogenes PrfA dependent virulence (LIPI-1) gene cluster was demonstrated in hemolytic L. innocua. L. innocua usually considered non-pathogenic versus pathogenic L. monocytogenes and L. ivanovii because of the main virulence gene loss. There are limited studies and reports available about L. innocua-caused illness in cattle. A total of 18 STs were identified in cattle abortions while 17 STs in the farm environment with majority of STs were present in both abortions and environmental samples. Genome sequencing showed that in one farm identical L. innocua clones were represented in water, feed, soil, and faeces sample groups, suggesting that animals most likely through the faecal shedding may remain as the main source of L. innocua in a farm environment. Out of all L. innocua isolates PrfA-dependent virulence genes were not found in aborted foetuses isolates and environmental L. innocua isolate groups; however, in 20% of isolates a complete LIPI-3 pathogenicity island encoding listeriolysin S was identified. In this study, we demonstrated that genetically diverse L. innocua clones were widely distributed in cattle farm environment and certain isolates had a significant pathogenicity potential for cattle, thus causing adverse health effects, including abortions.

Giardia duodenalis is a waterborne zoonotic protozoan that causes gastrointestinal tract inflammation in humans, cattle, and other animals. The aim of the present study was to estimate the prevalence and potential risk factors for Giardia infection in cattle in Latvia. During 2020–2021, a total of 973 individual faecal samples from cattle aged from 1 day to 12 years old, from 32 cattle herds, were tested for Giardia cyst presence with immunofluorescence staining followed by Giardia assemblage differentiation targeting beta-giardin gene. Using a questionnaire, information was collected to estimate the potential risk factors for G. duodenalis infection in cattle herds. Giardia was found in 8.4% of the examined cattle with a mean intensity of 5756 cysts per gram of faeces. The highest prevalence was observed in the 0 to 3-month-old calves (16.4%). At least one Giardia shedding animal was found in 27 herds with an overall prevalence of 84.4%. Significantly higher prevalence was found for cattle infected with G. duodenalis assemblage E compared to that infected with assemblage A: 88.7% and 11.3%, respectively. Protective factors such as age and rodent control and change of shoes were found to be significant for Giardia infection, while isolating calves for diarrhoea and water bodies (ponds/lakes) in pasture were potential risk factors in Latvian cattle.

Fish and fish products are a food group with a high nutritional value, however, the fish may contains a variety of microorganisms, which may cause foodborne infection outbreaks in humans after consumption. The aim of the present study was to identify the bacterial microflora of skin, gill and gut of roach caught in river. Altogether, nine roach (Rutilus rutilus) samples were collected from fishermen from Driksna river in Latvia. Skin, gills and gut samples were investigated for total bacterial count (TBC), coliforms and Enterobacteriaceae. Pooled skin, muscles and internal organ samples were examined for presence of pathogens – Salmonella spp., Listeria spp. and Yersinia spp. in accordance with ISO standards. Identification of bacterial species was performed with MALDI-TOF MS Biotyper. TBC ranged from 1.96 to 5.16 log10 CFU g-1, coliforms from 0 to 3.66 log10 CFU g-1 and Enterobacteriaceae from 0 to 4.16 log10 CFU g-1 in roach skin, gills and gut samples. The highest counts of TBC, coliforms and Enterobacteriaceae was found in roach gills and gut samples, while there were no significant differences between the TBC in skin, gills and gut (p

Identification of microorganisms by MALDI-TOF MS Biotyper has been demonstrated to be accurate, rapid and lower cost than conventional food investigation methods. Rapid identification of pathogenic and spoilage microorganisms is crucial for dairy industry to ensure the quality and safety of milk and milk products. In this study, the bacterial species representing the Enterobacteriaceae family were identified in raw milk and milk products using the MALDI-TOF MS mass spectrometry. Altogether, 20 samples of Slovak milk and milk products were examined. Samples were cultured on VRBG agar at 37 °C for 24-48 h. Typical bacterial colonies were selected for identification with MALDI-TOF MS Biotyper. Escherichia coli and Enterobacter sp. were the most abundant Enterobacteriaceae family representatives identified. E. coli was found in nine and Enterobacter sp. in eight samples. Enterobacter sp. comprised 49 % and Escherichia coli 23 % of all bacterial isolates. The study shows that MALDI-TOF MS Biotyper was reliable identification method of Enterobacteriaceae in milk and dairy products. This method was helpful in evaluation of bacterial contamination of milk.

Bacterial species of Enterobacteriaceae and the antimicrobial resistance of the isolates were detected in Apis mellifera L. bees gut. Gut content was cultivated on Meat peptone and McConkey agars at 30 and 37 °C, then, the isolates were identified with MALDI TOF MS Biotyper. Isolated strains were tested for antibiotic resistance to penicillins, cephalosporins, carbapenems, fluoroquinolones and aminoglycosides. Altogether, 12 species representing Enterobacteriaceae family were isolated. Firmicutes and Candida were represented by Bacillus megaterium and Issatchenkia orientalis . Isolated Enterobacteriaceae species were Enterobacter cloacae, Hafnia alvei, Klebsiella oxytoca, Morganella morganii, Serratia marcescens, Ser. liquefaciens, Raoultella ornithinolytica, R. planticola, R. terrigena, Pantoea ananatis, P. agglomerans, Rahnella aquatilis. Enterobacter cloacae, Hafnia alvei, Klebsiella oxytoca, Morganella morganii, Serratia marcescens, Ser. liquefaciens isolates exhibited the antimicrobial resistance more frequently than Raoultella ornithinolytica, R. planticola, R. terrigena, Pantoea ananatis, P. agglomerans, Rahnella aquatilis. Microflora of gut of bees could serve as a source of resistant microorganisms.

The honey bee, Apis mellifera, is critically important for the pollination of many economically important crops. Continued colony losses have called for a deeper understanding of both symbiotic and pathogenic microbial interactions, particularly as they relate to food storage and the pollination environment. Therefore, the aim of this study was to explore and characterize the bacteria colonizing the alimentary tract of the native honey bees using MALDI TOF MS Biotyper. Content of the intestinal tract was cultured for isolation of Gram-negative, Gram-positive microorganisms and yeasts. Then, the identification of isolates with MALDI-TOF MS Biotyper was done. Results showed that the most abundant genera in bees’ samples were Lactobacillus, Pseudomonas and Serratia. Altogether, 12 genera with 21 bacterial species and one yeast genus with two species were isolated. Bacteria were represented with Acidovorax facilis, Lactobacillus gasseri, L. amylovorus, L. kunkeei, L. fructivorans, Pseudomonas oryzihabitans, Ps. brenneri, Ps. indica, Micrococcus luteus, Serratia fonticola, Ser. marcescens, Ser. ureilytica, Hafnia alvei, Candida magnolia, Bacillus oleronius, B. horneckiae, Issatchenkia orientalis, Pantoea agglomerans, Enterobacter cloacae, Staphylococcus epidermidis, Staph. pasteuri, Shewanella profunda. The results of the study shows that the microflora of the bees gut is heterogenic and depend of locality and resources of environment for bees.

Knowledge of composition of bee gut microbiota is important to ensure balanced gut microbiota and improve the health status of bees. The aim of the present study was to detect the microorganisms in gut of honey bee and to study their antimicrobial resistance and antimicrobial activity against three essential oils. Content of bees gut was studied with microbiological methods, and isolates were confirmed with MALDI TOF mass spectrometry. Isolated species were tested for antibiotic resistance to ciprofloxacin, levofloxacin, amikacin and gentamicin. For antimicrobial activity, essential oils of Abies alba, Pinus mugo and Pinus sylvestris were used. Gram-positive bacteria Bacillus oleronius, Micrococcus luteus, Staphylococcus epidermidis and three Gram-negative bacteria Pseudomonas oryzihabitans, Serratia fonticola, Serratia marcescens were isolated from bees gut. Antibiotic resistance was found in Gram-negative bacteria, while the Gram-positive bacteria were sensitive to all antibiotic tested. The best antibacterial activity of essential oils found against Gram-positive bacterial strains. Essential oils can be a potential sources of compounds with antimicrobial activity on Gram-positive isolates of bees gut.

Grape pomace is a winery industry residue of skins, seeds and stems of grapes used in agriculture for animal feed and production of food with biological activity. The aim of this study was to evaluate antimicrobial activity of Vitis vinifera L. pomace extract on growth of microscopic fungi and bacteria. The four strains of bacteria (two Gram-positive bacteria Staphylococcus aureus CCM 2461, Bacillus cereus CCM 2010; two Gram-negative bacteria Escherichia coli CCM 3988, Pseudomonas aeruginosa CCM 1959) and four yeasts strains (Candida albicans CCM 8186, Candida glabrata CCM 8270, Candida krusei CCM 8271 and Candida tropicalis CCM 8223) were studies. For detection of antimicrobial activity, the grape pomace extracts of white variety Pálava and red variety Dornfelder were used. Pálava pomace extracts were less efficient against the microorganisms tested and Dornfelder extracts were more active against Gram-positive bacteria and yeasts.

Essential oils may inhibit Gram-negative microbiota, a causative agent of spoilage of fresh fish. The aim of this study was to detect antibacterial activity of essential oils against Gram-negative bacteria isolated from fish. The antimicrobial activity of Citrus paradisi peel oil, Citrus reticulata peel oil, Juniperus communis fruit oil, Eucalyptus globulus leaf oil and Cananga odorata flower oil was studied. The microorganisms tested were Pseudomonas fluorescens, P. frederiksbergensis, P. gessardii, P. ludensis, P. proteolitica, Shewanella baltica, Yersinia ruckeri and Y. enterocolitica. Essential oils were tested with disc diffusion method and method of minimal inhibition concentration. The best antimicrobial activity of Cannaga odorata flower peel oil and Juniperuss communis fruit oil was found against Pseudomonas spp. and less against Shewanella baltica, Yersinia ruckeri and Y. enterocolitica. Citrus paradisi peel oil and Citrus reticulata peel oil were most active against Yersinia spp. Eucalyptus globulus leaf oil showed good antimicrobial effect against Shewanella baltica.

Cheese is one of the most important products of dairy industry from the economic and nutritional points of view that demands the high processing technology and production hygiene. The aim of the study was to evaluate microbiological quality of traditional Slovak cheese “Parenica” produced from sheep milk. The coliforms, enterococci, lactic acid bacteria and microscopic filamentous fungi were detected in cheese samples. MALDI-TOF MS was applied for identification of isolates. In group of lactic acid bacteria three genera were identified: Lactococcus and Leuconostoc. Lactobacillus spp. was the most abundant genus, which was found in 25, Leuconostoc in 10 and Lactococcus in 7 samples. Lactobacillus was mostly represented with four species: Lactobacillus plantarum, L. acidophilus, L. ultunensis, L. casei. Another bacterial isolates included Gram-positive and Gram-negative Enterococcus faecium, Streptococcus, Raoutella ornithinolytica and Klebsiela oxytoca. Our study shows that MALDI-TOF MS could serve as an important method for identifying microorganisms for dairy industry needs.

Research on insects and their bacterial communities provides valuable information on potential interaction between the host and their symbiotic bacteria. The aim of the present study was to evaluate antimicrobial activity of essential oils against Staphylococcus spp. isolated from spiders. Spiders samples were investigated microbiologically and Staphylococcus isolates were confirmed with MALDI TOF MS Biotyper. Antimicrobial activity of Satureja hortensis L., Pimpinella anisum L., Rosmarinus officinalis L., Salvia officinalis L. and Ocimum basilicum L. essential oils was detected. Altogether five Staphylococcus species were identified: S. capitis, S. epidermidis, S. haemolyticus, S. warneri and S. xylosus. All bacterial strains were resistant of ciprofloxacin, levofloxacin, amikacin and gentamicin. S. haemoliticus was the most resistant against essential oils of Rosmarinus officinalis L., Salvia officinalis L. S. warneri and S. xylosus were the most sensitive against antimicrobial action of the applied EOs.

The aim of this study was to evaluate antimicrobial activity of Lactobacillus kunkeei of bee’s gastrointestinal tract (GUT) against pathogenic bacteria isolated from bees’ gut. Content of the intestinal tract microbiota was cultured for isolation of different group of bacteria. Gut homogenates were plated on de Man, Rogosa and Sharpe agar plates and incubated for 48-72h at 30 °C anaerobically; on McConkey agar and incubated for 24-48h at 37°C aerobically. Then, the identification of isolates with MALDI-TOF MS Biotyper was done. The bacterial strains of Lactobacillus kunkeei, Bacillus cereus, Bacillus megatherium, Bacillus simplex, Bacillus thuringiensis, Delfia acidovorans, Escherichia coli, Enterococcus faecalis, Klebsiella aerogenes, Morganella morganii, Pseudomonas aeruginosa, Serratia marcescens and Sphingomonas parapaucimobilis were isolated from gut content of bees. The disc diffusion method was used for the determination of antimicrobial activities of the Lactobacillus kunkeei supernatant against other isolated bacterial strains of bees’ origin. The best antimicrobial activity of Lactobacillus kunkeei supernatant was found against Klebsiella aerogenes, Morganella morganii, Pseudomonas aeruginosa, Serratia marcescens. Less effective the L. kunkeei supernatant was against Bacillus cereus, Bacillus megatherium, Bacillus simplex, Bacillus thuringiensis. The moderate antibacterial activity was identified against Delfia acidovorans, Escherichia coli, Enterococcus faecalis, Sphingomonas parapaucimobilis.

Fungi as a group are some of the most resilient spoilage microorganisms and are capable of overcoming the control strategies utilized by the food industry. Various fungal propagules are rapidly dispersed by water and air, survive under extreme conditions, and sustainably increase in biomass. The aim of this study were isolation and identification of microscopic filamentous fungi from traditional cow cheese. Altogether, 40 samples of Slovak traditional cheese “Parenica“ were examined. The samples included non-smoked and smoked cheese samples. Microscopic fungi were cultivated on Malt extract agar. Microscopic fungi count was from 1.89 log cfu.g-1 to 2.65 log cfu.g-1. A total of 129 isolates of microscopic fungi were identified in our study. Alternaria and Penicillium (50%) were the most abundant microscopic fungi. Also Aspergillus (45%) and Cladosporium (45%) were frequently identified. Alternaria sp., Aspergillus niger, Aspergillus sp., Cladosporium sp., Mucor sp., Penicillium sp. and Rhizopus sp. were isolated from non-smoked and smoked cheese.

Different strains of lactic acid bacteria (LAB) could be identified in cheeses made in accordance with national recipes. This strains of LAB are not within the starter cultures used in the dairy industry. The aim of the present study was to identify LAB in traditional cow’s milk cheeses of Slovakia. An amount of 40 samples of cheese were produced in the four regions of the Slovakia. LAB were cultured on de Man, Rogosa and Sharpe media for 48 h at 37 °C microaerophilically. The of LAB were confirmed with MALDI-TOF. LAB colonies were subcultured on TSA and 166 cultures were used for further confirmation. The following genera and species were identied with mass spectrometry method: Lactococcus spp., including L. lactis and L. garvieae; Lactobacillus spp., including L. curvatus, L. delbrueckii, L. fermentum, L. papacasei, L. paraplantarum, L. plantarum and L. sakei; Enterococcus spp., including E. durans, E. faecalis, E. faecium and E. italicus; Leuconostoc spp., including L. mesenteroides; Pediococcus spp. with P. pentosaceus and Streptococcus spp. with S. salivarius ssp. thermophilus.

Wine has long been under the view of researchers to test it for prospective benefits to human health. Many recent studies have claimed how moderate consumption of wine, can be beneficial for us. The aim of this study was to assess antagonistic activity and probiotic potential of the LAB strains, Lactobacillus brevis, Lactobacillus hilgardii and Lactobacillus plantarum, isolated from wine against pathogenic bacteria. The antimicrobial activity was detected with disc diffusion method against five species of Gram-negative bacteria: Escherichia coli CCM 3988, Klebsiella pneumoniae CCM 2318, Salmonella enterica subsp. enterica CCM 3807, Shigella sonei CCM 1373, Yersinia enterocolitica CCM 5671 and five Gram-positive bacteria: Bacillus thuringiensis CCM 19, Enterococcus faecalis CCM 4224, Listeria monocytogenes CCM 4699, Stapylococcus aureus subsp. aureus CCM 2461, Streptococcus pneumonia CCM 4501. These results showed antagonistic activity and probiotic potential of pathogenic bacteria isolated from wine. The cell free supernatants (CFS) from Lactobacillus brevis, Lactobacillus hilgardii and Lactobacillus plantarum inhibited the growth of pathogenic bacteria.

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 aim of this study was to investigate the microbiological quality of chicken’s thighs meat after application of Thymus serpyllum and Ocimum basilicum essential oils with combination of vacuum packaging and EDTA treatment. The microbiological quality of control samples without vacuum packaging, vacuum packed with and without EDTA treatment, vacuum packed and treated with EDTA and samples treated with the essential oils of basil and breckland thyme were followed for 16 days. Microbiological analyses were conducted with standard microbiological methods. For anaerobic plate count, PCA agar was inoculated and incubated for 2 days at 35°C anaerobically. Pseudomonas spp. count was determined on Pseudomonas Isolation agar after incubation at 48 h at 25°C. For lactic acid bacteria (LAB), MRS agar was inoculated and incubated for 48-78 h at 37°C microaerophilly. For Enterobacteriaceae, VRBG agar was inoculated and incubated at 37°C for 24 h. Anaerobic plate count ranged from 2.89 log CFU/g in all tested group on 0 day to 5.19 log CFU/g on 16 day in control group stored in air. LAB count ranged from 3.01 log CFU/g in all tested group on 0 day to 4.08 log CFU/g on 16 day in control group stored in air. Enterobacteriacea counts were from 1.33 log CFU/g on 0 day to 5.11 on 16 day in control group stored in air. Pseudomonas spp. were found only in control group stored in air on 12 and 16 day. The results of the present study suggest the possibility of application of Thymus serpyllum and Ocimum basilicum essential oils as natural food preservatives and potential sources of antimicrobial ingredients for food industry.

The aim of the present study was to evaluate antimicrobial and antioxidant activity of Melissa officinalis L. and Mentha piperita L. from Lamiaceae species (The detection of antimicrobial activity was carried out by disc diffusion method and evaluation of minimal inhibition concentration against five Gram-negative bacteria: Escherichia coli CCM 3988, Klebsiella pneumoniae CCM 2318, Salmonella enterica subsp. enterica CCM 3807, Shigella sonei CCM 1373, Yersinia enterocolitica CCM 5671 and five Gram-positive bacteria: Bacillus thuringiensis CCM 19, Clostridium perfringens CCM 4435, Haemophilus influenzae CCM4456, Listeria monocytogenes CCM 4699, Staphylococcus aureus subsp. aureus CCM 2461. Antioxidant activity was determined by DPPH radical scavenging and phosphomolybdenum antioxidant methods. The content of polyphenols and flavonoids was measured by colorimetric methods. Both tested plants showed the highest antimicrobial activity against Gram-negative bacteria confirmed by both methods - disc diffusion and minimal inhibitory concentration. Additionally, both tested plants exhibited high antioxidant activity. The highest content of total polyphenol (37.37 mg GAE/g g) was identified in lemon balm, but flavonoids (33.90 µg QE/g) in peppermint.

The aim of the present work was monitoring chicken thighs microbiological quality after treatment by ethylenediaminetetraacetate (EDTA), coriander (Coriandri aetheroleum) and spearmint (Menthae spicata aetheroleum) essential oil, stored under vacuum packaging, at 4±0.5°C for a period of 16 days. The following treatments of chicken thighs were used: Air-packaging control samples, control vacuum-packaging samples, vacuum-packaging with EDTA solution 1.50% w/w, control samples, vacuum-packaging with Menthae crispae aetheroleum essential oil at concentrations 0.2% v/w and vacuum-packaging with Coriandri aetheroleum essential oil at concentration 0.2% v/w. The quality assessment of all samples was established by microbiological analysis. The microbiological parameters as the total viable count, Enterobacteraceae genera counts, lactic acid bacteria and Pseudomonas spp. were detected. The results of this present study suggest the possibility of application the essential oil of Coriandri aetheroleum and Menthae spicata aetheroleum as natural food preservatives and potential sources of antimicrobial ingredients for food industry

Medicinal plants are traditionally used for the treatment in human medicine. The antibacterial activity of ethanol extract of four plant species (Achillea millefolium L., Agrimonia eupatoria, Melissa officinalis and Tilia platyphyllos) applied in the traditional medicine in Slovakia were tested. Extracts of certain parts of these plants were tested in vitro against six bacterial species (Bacillus cereus, Enterococcus faecalis, Escherichia coli, Lactobacillus brevis, Lactobacillus hilgardii and Serratia rubidea) strains using the disc diffusion method and microbroth dilution method. Minimum inhibitory concentrations for the extracts against all the microorganisms were determined by serial dilutions. All the extracts demonstrated antibacterial activity against Gram-positive bacteria and partially against Gram-negative bacteria.

Legionella is an opportunistic pathogen with a biphasic life cycle that occasionally infects humans. The aim of the study was to assess the distribution of virulence genes and genetic diversity among L. pneumophila isolated from water supply systems of residential buildings in Latvia. In total, 492 water samples from 200 residential buildings were collected. Identification of Legionella spp. was performed according to ISO 11731, and 58 isolates were subjected to whole-genome sequencing. At least one Legionella-positive sample was found in 112 out of 200 apartment buildings (56.0%). The study revealed extensive sequence-type diversity, where 58 L. pneumophila isolates fell into 36 different sequence types. A total of 420 virulence genes were identified, of which 260 genes were found in all sequenced L. pneumophila isolates. The virulence genes enhC, htpB, omp28, and mip were detected in all isolates, suggesting that adhesion, attachment, and entry into host cells are enabled for all isolates. The relative frequency of virulence genes among L. pneumophila isolates was high. The high prevalence, extensive genetic diversity, and the wide range of virulence genes indicated that the virulence potential of environmental Legionella is high, and proper risk management is of key importance to public health.

Giardia duodenalis Styles, 1902 is an infectious agent which can cause enteritic disease in cattle (Bos taurus Linnaeus, 1758) worldwide. As a zoonotic protozoan, it is important to acknowledge Giardia prevalence and assemblages found in cattle and risk factors associated with the Giardia infection in herds. This systematic review aims to estimate the prevalence of G. duodenalis and its assemblages in cattle and to identify the risk factors associated with Giardia infection in cattle in Europe. A systematic review was performed according to Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines to collect information from published studies in Europe. A total of 1414 studies were identified and 17 relevant studies were included in this review. Mean Giardia prevalence in cattle in Europe was 35.1%, with the highest prevalence found in neonatal animals (39.6%), but mean heard prevalence was 67.0%. Mixed infections of Giardia assemblages A and E were found most frequently (55.6%), while assemblages A and B were found more frequently in animals under 24 months old. Risk factors, such as deep litter with run-out, prolonged calf contact with the dam, and seasonality, such as winter and spring, were found to be potential risk factors for Giardia presence in the herds.

The aim of the present study was to describe the microbial groups of the traditional Slovak cheese Parenica during rippening. The microbial group included the total bacterial count, coliform bacteria, enterococci, lactic acid bacteria, and microscopic filamentous fungi, which may affect the organoleptic characteristics of this product. A total of 42 cheese samples were collected from four different farms during three months. The total bacterial counts were cultivated on Plate count agar at 30 °C, lactic acid bacteria (LAB) on MRS, APT and MSE at 37 °C, coliform bacteria on VRBL at 37 °C. Gram-positive and Gram-negative isolates were identified by MALDI-TOF MS profiling. Bacillus sp. and Enterococcus faecium were the most frequently identified species of bacteria. Candida kefyr was the most distributed yeast according to microbiological methods. Lactic acid bacteria group was represented by Lactobacillus helveticus, L. jensenii, L. alimentarius, L. crispatus, L. curvatus, L. fermentum, L. suebicus, L. delbrueckii ssp. lactis, L. paracasei ssp. paracasei, Lactococcus lactis ssp. lactis, Leuconostoc lactis and Le. mesenteroides ssp. mesenteroides . This report describing the indigenous microbiota of the traditional raw milk cheeses from Slovakia. Our results provide useful information on occurrence of valuable microbial strain for the industrialization of producing of the traditional dairy products in Slovakia.

The fish meat is an essential part of human diet. However, fish may be contaminated with different microorganisms, including pathogens. Antimicrobial resistance of fish microbiota may facilitate the spread of resistant microorganisms causing serious consequences for human health. The aim of the present study was to detect bacterial contamination in fish gill, gut and skin and to determine antimicrobial susceptibility of the bacterial isolates. Rainbow trout (Oncorhynchus mykiss) and bream (Abramis bram) were obtained from the market in Jelgava city. Chub (Leuciscus cephalus), crucian carp (Carassius carassius) and tench (Tinca tinca) were collected from fishermen. Fish samples were examined for the total bacterial count (TBC), coliforms, Enterobacteriaceae, Pseudomonas spp. and Aeromonas spp. Testing was done in accordance with International Organization for Standardization (ISO) standards. Identification of all bacteria was accomplished with the Matrix Assisted Laser Desorption Ionization – Time of Flight Mass Spectrometry (MALDI-TOF MS) method. The disc diffusion method was used for the detection of antibiotic susceptibility of isolated bacterial species. TBC ranged from 2.70 to 7.00 log CFU.g-1, coliforms from 0 to 2.67 log CFU.g-1, Enterobacteriaceae from 0 to 2.85 log CFU.g-1. The highest contamination with Pseudomonas spp. and Aeromonas spp. was observed in chub gut samples with 1.60 log CFU.g-1 and 2.23 log CFU.g-1, respectively. Altogether, 16 microbial genera and 31 bacterial species were identified. The dominant bacterial species belonged to Pseudomonas spp. (54%) and Enterobacteriaceae. Pseudomonas spp. were resistant to ticarcillin, susceptibility to ciprofloxacin showed 88% of isolates. All Enterobacteriaceae isolates were susceptible to imipenem. The microbial quality of the fish was acceptable, but the presence of antibiotic resistant bacteria may further cause a negative impact on public health.

The research was aimed to study the impact of sous vide thermal treatment on the microbiological quality of fresh turkey breast meat after treatment with thyme and rosemary EOs and the survival of Listeria monocytogenes on the turkey meat samples. The samples were vacuum-packed and cooked at 55 °C, 60 °C, and 65 °C for 5, 15, 30 and, 60 min. There was an amount of 5 g (5 ±0.2 g) of the sample placed in PA/PE film bags and inoculated with 100 μL of L. monocytogenes inoculum. The sample was incubated at 37 °C for 18 h after bag sealing. The samples were tested on the 1st and 3rd days of experiments. The microbiological quality of fresh turkey breast meat was assessed by the detection of total microbial counts and meat microbiota was identified by mass spectrometry using MALDI-TOF MS Biotyper (Bruker Daltonics, Germany). Microbial counts differed significantly depending on temperature and time and the microbial counts ranged from 2.21 log cfu.g-1 to 8.26 log cfu.g-1 on the 1st and 3rd day of the experiment. The study shows that the sous vide method with essential oils combination is an effective method and it can be used to protect the microbiota of turkey meat and L. monocytogens survival, however, the quality of raw material is crucial.

Arthropods are reported to serve as vectors of transmission of pathogenic microorganisms to humans, animals, and the environment. The aims of our study were (i) to identify the external bacteriota of spiders inhabiting a chicken farm and slaughterhouse and (ii) to detect antimicrobial resistance of the isolates. In total, 102 spiders of 14 species were collected from a chicken farm, slaughterhouse, and buildings located in west Slovakia in 2017. Samples were diluted in peptone buffered water, and Tryptone Soya Agar (TSA), Triple Sugar Agar (TSI), Blood Agar (BA), and Anaerobic Agar (AA) were used for inoculation. A total of 28 genera and 56 microbial species were isolated from the samples. The most abundant species were Bacillus pumilus (28 isolates) and B. thuringensis (28 isolates). The least isolated species were Rhodotorula mucilaginosa (one isolate), Kocuria rhizophila (two isolates), Paenibacillus polymyxa (two isolates), and Staphylococcus equorum (two isolates). There were differences in microbial composition between the samples originating from the slaughterhouse, chicken farm, and buildings. The majority of the bacterial isolates resistant to antibiotics were isolated from the chicken farm. The isolation of potentially pathogenic bacteria such as Salmonella, Escherichia, and Salmonella spp., which possess multiple drug resistance, is of public health concern.

The aim of this study was to isolate and identify bacteria and yeasts in different grape samples. The samples were collected in September 2017. Used 13 grape samples in this study (9 white and 4 red) were from the local Slovak winemakers. Alibernet, Irsai Oliver, Dornfelder, Blue Frankish, Feteasca regala, Green Veltliner, Pálava, Mūller Thurgau, Rhinriesling, Cabernet Savignon, Pinot Blanc, Savignon Blanc and Welschriesling. Two cultivation media were used for detection of bacteri and yeasts in grape samples. Malt extract agar base (MEA) and Tryptone Soay agar (TSA) were used for the cultivation of bacteria and yeasts. Cultivation was performed by spread plate method. Ethanol/formic acid extraction procedure was used for preparation of samples. MALDI-TOF Mass Spectrometer (Microflex LT/SH) (Bruker Daltonics, Germany) was used for identification of bacteria and yeasts. In total, 8 genera of yeasts, 8 genera of Gram-negative bacteria and 10 of Gram-positive bacteria were identified. Together 333 isolates, yeasts, Gram-negative and Gram-positive bacteria were identified.

Yersinia enterocolitica is an important foodborne pathogen, and the determination of its virulence factors and genetic diversity within the food chain could help understand the epidemiology of yersiniosis. The aim of the present study was to detect the prevalence, and characterize the virulence determinants and genetic diversity, of Yersinia species isolated from meat. A total of 330 samples of retailed beef (n = 150) and pork (n = 180) in Latvia were investigated with culture and molecular methods. Whole genome sequencing (WGS) was applied for the detection of virulence and genetic diversity. The antimicrobial resistance of pathogenic Y. enterocolitica isolates was detected in accordance with EUCAST. Yersinia species were isolated from 24% (79/330) of meats, and the prevalence of Y. enterocolitica in pork (24%, 44/180) was significantly higher (p < 0.05) than in beef (13%, 19/150). Y. enterocolitica pathogenic bioserovars 2/O:9 and 4/O:3 were isolated from pork samples (3%, 6/180). Only resistance to ampicillin was confirmed in Y. enterocolitica 4/O:3 and 2/O:9 isolates, but not in other antimicrobials. Major virulence determinants, including ail, inv, virF, ystA and myfA, were confirmed with WGS in Y. enterocolitica 2/O:9 and 4/O:3. MLST typing revealed 15 STs (sequence types) of Y. enterocolitica with ST12 and ST18, which were associated with pathogenic bioserovars. For Y. enterocolitica 1A, Y. kristensenii, Y. intermedia and Y. frederiksenii, novel STs were registered (ST680-688). The presence of virulence genes and genetic characteristics of certain Y. enterocolitica STs confirm the common knowledge that pork could be an important source of pathogenic Yersinia.

Listeria monocytogenes can cause disease in humans and in a wide range of animal species, especially in farm ruminants. The aim of the study was to determine the prevalence and genetic diversity of L. monocytogenes related to 1185 cattle abortion cases in Latvia during 2013–2018. The prevalence of L. monocytogenes among cattle abortions was 16.1% (191/1185). The seasonality of L. monocytogenes abortions was observed with significantly higher occurrence (p < 0.01) in spring (March–May). In 61.0% of the cases, the affected cattle were under four years of age. L. monocytogenes abortions were observed during the third (64.6%) and second (33.3%) trimesters of gestation. Overall, 27 different sequence types (ST) were detected, and four of them, ST29 (clonal complex, CC29), ST37 (CC37), ST451 (CC11) and ST7 (CC7), covered more than half of the L. monocytogenes isolates. Key virulence factors like the prfA-dependent virulence cluster and inlA, inlB were observed in all the analyzed isolates, but lntA, inlF, inlJ, vip were associated with individual sequence types. Our results confirmed that L. monocytogenes is the most important causative agent of cattle abortions in Latvia and more than 20 different STs were observed in L. monocytogenes abortions in cattle.

Natural products of plant origin, which include essential oils (EO) could be used as a growth inhibitor of pathogenic and spoilage microflora in food. The objective of this study was to determine the antibacterial and antioxidant activity of 21 EO against 10 Pseudomonas species isolated from freshwater fish. The chemical composition of EO was determined by gas chromatography/mass spectrometry. The disc diffusion method and detection of minimum inhibitory concentration (MIC) were used for the determination of the antimicrobial activity. All the EO tested exhibited antimicrobial activity, however, Cinnamomum zeylanicum EO was the most effective against Pseudomonas spp. both according to the disc diffusion and MIC methods. The EOs of Cymbopogon nardus, Origanum vulgare, Foeniculum vulgare and Thymus serpyllum showed the highest antioxidant activity of 93.86 μg, 83.47 μg, 76.74 μg and 74.28 μg TEAC/mL. Application of EO could be an effective tool for inhibition of growth of Pseudomonas spp. on fish. Keywords: Essential oils, Antimicrobial activity, Chemical composition, Antioxidant activity, Pseudomonas

Introduction and objective Salmonella is a foodborne pathogen which causes gastrointestinal illness in consumers, and exhibits resistance to antimicrobials of eterinary and clinical significance. The aim of this study is to detect the prevalence and antimicrobial resistance of Salmonella isolates from meat in Latvia. Material and Methods A total of 3,152 samples of raw and ready-to-eat (RTE) meats were collected during the official control and in-house control procedures in 2015. Samples were tested in accordance with ISO 6579:2002. All S. Typhimurium, S. Enteritidis and other isolates recovered from the official control samples (S. Derby, S. Give) were tested for antimicrobial resistance. The minimum inhibitory concentration (MIC) values were investigated in line with the requirements of the European Committee on Antimicrobial Susceptibility Testing (EUCAST). Results The prevalence of Salmonella was 0.8% (25/3152). The highest prevalence (1.5%) of Salmonella was found in minced meat and meat preparations (7/481), while the lowest (0%) in frozen meat and meat preparations (0/349) and RTE meats (0/364). The most common serovars were S. Typhimurium (36%, 9/25) and S. Derby (32%, 8/25). In total, 62% (13/21) of Salmonella isolates were resistant to at least one antimicrobial agent. Altogether, 40% (8/20) of isolates were resistant to sulfamethoxazole, 25% (5/20) to nalidixic acid, ciprofloxacin, ampicillin and 20% (4/20) to tetracycline. All isolates were susceptible to ceftazidime, cefotaxime, meropenem, azithromycin and tigecycline. S. Typhimurium exhibited antimicrobial resistance more often (87.5%) than other serovars. Conclusions The study shows that the presence of Salmonella in meat, together with the high prevalence of resistant strains, is a significant public health related issue in Latvia.

Resveratrol is commonly found in food and drinks, including red wine and grapes. Grape extracts have a potent antimicrobial activity in vitro. The antimicrobial activity of plant extracts is the base of their potential application in food preservation agents, pharmaceuticals, cosmetics, alternative drugs and natural therapies. The aim of our study was to evaluate the antimicrobial activity of resveratrol and Blue Frankish pomace extract against Grampositive and Gramnegative bacteria as well as yeasts from the genus Candida. Six bacterial strains (three Grampositive bacteria Staphylococcus aureus CCM 2461, Enterococcus faecalis CCM 4224 and Listeria monocytogenes CCM 4699; three Gramnegative bacteria Escherichia coli CCM 3988, Pseudomonas aeruginosa CCM 1959 and Salmonella enteritidis subsp. enteritidis CCM 4420) and three yeast strains (Candida albicans CCM 8186, Candida krusei CCM 8271 and Candida tropicalis CCM 8223) were evaluated using the antimicrobial assay. Pure resveratrol and grape pomace extracts of red variety Blue Frankish were used. Our results show that resveratrol and red grape pomace extract have a very good antimicrobial activity against Grampositive bacteria when compared with Gramnegative bacteria and yeasts.

The wine grape berries share a complex microbial ecology including filamentous fungi, yeasts and bacteria. The microbiota reveals different physiological characteristics and depends on the grape ripening stage and the availability of nutrients with different effect on wine production. The microbiota of grape berries (n = 12) was isolated and identified in the present study. The samples were collected in September 2018. Grape berries were obtained from Vrbovo vineyard located in Slovakia. The grape berries investigated belonged to Blue Frankish, Cabernet Sauvignon, Chardonnay, Dornfelder, Feteasca regala, Green Veltliner, Irsai Oliver, Mūller Thurgau, Pálava, Pinot Blanc, Rhinriesling and Welschriesling varieties. The microorganisms were cultivated on Malt extract agar (MEA) at 25 °C for five days in aerobically for microscopic filamentous fungi and Tryptone Soya agar (TSA) at 37 °C for 24 – 48 h aerobically for bacteria and yeasts. Total bacterial counts on different wine grape berries ranged from 2.57 ±0.09 in Chardonnay to 4.39 ±0.21 log CFU.g-1 in Pálava. Microscopic filamentous fungi count ranged from 1.18 ±0.03 in Blue Frankish to 2.60 ±0.17 log CFU.g-1 in Welschriesling. MALDI-TOF MS Biotyper mass spectrometry was used for identification of microorganisms (bacteria and yeasts) and microscopic filamentous fungi with manuals. The most identified microscopic fungal species was Alternaria sp., for yeasts Issatchenkia orientalis and Leuconostoc mesenteroides subsp. mesenteroides for bacteria.

Listeria spp. is a diverse genus of Gram-positive bacteria commonly present in the environment while L. monocytogenes and L. ivanovii are well known human and ruminant pathogens. The aim of the present study was to reveal the prevalence and genetic diversity of L. monocytogenes and other Listeria spp. and to identify the factors related to the abundance of pathogen at cattle farms. A total of 521 animal and environmental samples from 27 meat and dairy cattle farms were investigated and the genetic diversity of L. monocytogenes isolates was studied with WGS. The prevalence of Listeria was 58.9%, while of L. monocytogenes it was −11%. The highest prevalence of L. monocytogenes was found in the environment—soil samples near to manure storage (93%), mixed feed from the feeding trough and hay (29%), water samples from farms drinking trough (28%) and cattle feces (28%). Clonal complexes (CC) of CC37 (30%), CC11 (20%) and CC18 (17%) (all IIa serogroup) were predominant L. monocytogenes clones. CC18, CC37 and CC8 were isolated from case farms and CC37, CC11 and CC18 from farms without listeriosis history. Only one hypervirulent CC4 (1%) was isolated from the case farm. Sequence types (STs) were not associated with the isolation source, except for ST7, which was significantly associated with soil (p < 0.05). The contamination of soil, feeding tables and troughs with L. monocytogenes was associated with an increased prevalence of L. monocytogenes at farms. Our study indicates the importance of hygienic practice in the prevention of the dissemination of L. monocytogenes in the cattle farm environment.

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.

Antimicrobials are widely applied in aquaculture for treatment of infectious diseases in fish. The increased antimicrobial resistance of fish pathogens to conventional antimicrobial treatment highlights the need for research on the antibacterial properties of natural products—in this case, essential oils (EOs). The aim of the present study was to detect the antimicrobial activity of the essential oils on pathogenic microorganisms found in freshwater fish. Freshwater fish isolates of Aerococcus spp., Aeromonas spp., Enterococcus spp., Escherichia spp., Pseudomonas spp., Shewanella spp., Yersinia spp., and Vagococcus spp. were tested for antimicrobial resistance and antimicrobial activity against 14 commercially available essential oils. Antimicrobial resistance was identified in Pseudomonas spp. isolates against cefepime and ciprofloxacin; while all Aeromonas, Enterococcus, and Yersinia isolates were fully susceptible. All tested EOs revealed antimicrobial activity against the tested freshwater fish isolates at different extents. Cinnamomum camphora exhibited strong antimicrobial activity against Aeromonas spp. (3.12 μL/mL), Enterococcus spp. (0.78–1.56 μL/mL), and Pseudomonas spp. with the MIC method. EOs of Gaultheria procumbens and Litsea cubeba showed strong antibacterial activity against Yersinia spp. and Vacococcus spp. (6.25 μL/mL). The study shows the antimicrobial activity of EOs against the most relevant freshwater fish pathogens and indicates the application opportunities in aquaculture.

Staphylococcus spp. is not only a commensal bacteria but also a major human pathogen that causes a wide range of clinical infections. Recent evidence suggests that Staphylococcus has the ability to colonize the reproductive system and to affect its structure and functions. The objective of this study was to determine the chemical properties and antibacterial effects of select essential oils (EOs): Amyris balsamifera L., Boswellia carterii Birdw., Canarium luzonicum (Blume) A. Gray, Cinnamomum camphora (L.) J. Presl., Cinnamomum camphora var. linaloolifera Y. Fuita, Citrus x aurantium L., Gaultheria procumbens L., Litsea cubeba (Lour.) Pers., Melaleuca ericifolia Smith., Melaleuca leucadendra L., Pogostemon cablin (Blanco) Benth., Citrus limon (L.) Osbeck, Santalum album L., and Vetiveria zizanoides (L.) Roberty against 50 Staphylococcus spp. cultures isolated from human semen, specifically Staphylococcus aureus, S. capiti, S. epidermidis, S. haemoliticus, and S. hominis. The disc diffusion and broth microdilution methods were used to assess the antimicrobial potential and to determine the minimum inhibitory concentration (MIC) of the selected EOs. The best anti-Staphylococcus activities were found with both methods for the essential oils of C. luzonicum (Blume) A. Gray, A. balsamifera, C. camphora, and P. cabli.

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 studies of plant bacterial endophytes, colonizing the plant tissues without any signs of diseases, are essential for understanding of ecological interactions. The aim of our study is to detect microbiological contamination and to assess the antimicrobial, antioxidant activity, total phenolic, carotenoid content, genome size, and ploidy of non-cultivated Rosa canina sampled from urban areas. Samples of Rosa canina fruits were collected in three locations in Slovakia. The highest total viable count and the Enterobacteriaceae count in fruits were 4.32 log CFU/g and 4.29 log CFU/g, respectively. Counts of the mesophilic anaerobic sporulating bacteria, Pseudomonas spp., and of the microscopic fungi and yeasts were 3.00, 2.15 log CFU/g, 3.65 log CFU/g, and 2.76 log CFU/g, respectively. Regarding the antimicrobial activity, Escherichia coli and Klebsiela oxytoca were the most sensitive species among the assayed microorganisms to the treatment with the ethanolic extracts of Rosa canina fruits. The fruits were rich in bioactive compounds, polyphenols, and carotenoids, that could be related to their antioxidant activity. Genome sizes of analyzed samples ranged from 2.3 to 2.96. DNA-based fingerprinting obtained by iPBS markers of the Rosa canina var. lapidicola Heinr. Braun., was characterized by some distinctive inserted loci. An interdisciplinary study was performed for the dog roses from different parts of Slovakia that resulted in deeper characterization of this species.

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.

The effect of caraway (CEO) and anise (AEO) essential oils as well as vacuum packaging (VP) in extending of the shelf life of fresh chicken breast meat stored at 4 °C was investigated. CEO and AEO were used at concentrations 0.2% v/w with and without VP. Microbiological properties of chicken breast meat were monitored over a 16 day period. The microbiological parameters as the anaerobic plate count (AC), Enterobacteraceae, lactic acid bacteria and Pseudomonas spp. counts were detected. The anaerobic plate counts ranged from 2.77 log cfu.g-1 in all tested group on 0 day to 5.45 log cfu.g-1 on 16 day in control group stored in air condition. The number of lactic acid bacteria ranged from 3.20 log cfu.g-1 in all tested group on 0 day to 4.75 log cfu.g-1 on 16 day in control group stored in air condition. Enterobacteriaceae counts ranged from 0.00 to 4.25 log cfu.g-1 on 16 day in control group stored in air condition. The number of Pseudomonas spp. ranged from 0.00 log cfu.g-1 in all tested group on 0 day to 2.65 log cfu.g-1 on 16 day in control group stored in air condition. Statistically significant differences (P≤0.001) were found among tested group in all tested microorganisms. Among the antimicrobial combination treatments were examined in the study, the as application of vacuum packaging, EDTA, and essential oils were the most effective against the growth of lactic acid bacteria and Enterobactericeae and to a less extent on anaerobic plate count. The results of this present study suggest the possibility of using the essential oil of caraway and anise as natural food preservatives and potential source of antimicrobial ingredients for chicken breast meat.

The purpose of this study was to determine in vitro antibacterial activity of selected teas (Assam: Indian black tea from Camellia sinensis, Pu-erh: darkpu-erh (shu) from Camellia sinensis, Sencha: Japanese green tea from Camellia sinensis) against five species of pathogenic microorganisms. In our study, we determined the total viable count (TVC), number of yeasts (Y) and number of Enterobacteriaceae genera (E). Then MALDI-TOF MS Biotyper identified colonies after cultivation. Evaluation of the antimicrobial activity was performed by disc diffusion method, well diffusion method and detection of minimum inhibitory concentration (MIC). For antibacterial activity, bacteria Escherichia coli CCM 2024, Yersinia enterocolitica CCM 5671, Klebsiella pneumonie CCM 2318, Staphylococus aureus CCM 2461 and Bacillus thurigiensis CCM19 were used. The inhibition zones were measured in mm in disc diffusion method and well diffusion method. The MIC of the individual extracts was measured spectrophotometrically. The high number of total viable count was found in Pu-erh tea (2.1 log CFU.g-1) and lowest number was found in Assam tea (0.7 log CFU.g-1). The high number of Enterobacteriacea genera was found in Pu-erh tea (2.03 log CFU.g-1) and lowest number was found in Assam tea (0 log CFU.g-1). The higher number of yeasts was found in Pu-erh tea (1.83 log CFU.g-1) and lowest number was found in Assam tea (0.3 log CFU.g-1). Mass spectrometry revealed seven Gram positive bacteria Bacillus cereus, B. mycoides, B. pumilus, Enterococcus durans, Staphylococcus epidermis, S. hominis, S. warneri, four Gram negative bacteria Acinetobacter junii, Hafnia alvei, Klebsiella pneumoniae, Sphingomonas spp. and two yeast Candida glabrata, Cryptococcus albidus. The results show that certain tea extracts are particularly active against various pathogenic bacteria. Tea extracts (Sencha, Rooibos, Mate, Assam) were found to have the strongest antibacterial activity against bacteria Staphylococcus aureus CCM 2461.

The aim of this study was to isolate and identify yeasts in different new wine "federweisser" samples. We collected the samples at the end of the August 2015 and in the middle of the September 2015. Used 15 new wine samples in this study (5 white and 10 red) were from the local Slovak winemakers. Irsai Oliver (3), Moravian Muscat (2), Agria/Turan (1), Dornfelder (3), Blue Frankish (3), Pinot Noir (1) and Saint Laurent (2). Three cultivation media were used for detection of yeasts in "federweisser" samples. Malt extract agar base (MEA), Wort agar (WA) and Wild yeast medium (WYM) were used for the cultivation of yeasts. Cultivation was performed by spread plate method. Ethanol/formic acid extraction procedure was used for preparation of samples. MALDI-TOF Mass Spectrometer (Microflex LT/SH) (Bruker Daltonics, Germany) was used for the identification of yeasts. We identified seven different strains of Saccharomyces cerevisiae (23; 70%), two strains of Kloeckera apiculata [teleomorph Hanseniaspora uvarum] (7; 21%), and one strain of Pichia kluyveri (1; 3%), Pichia occidentalis [anamorph Candida sorbosa] (1; 3%) and Metschnikowia pulcherrima (1; 3%) in 15 new wine "federweisser" samples. Saccharomyces cerevisiae was dominant species in each new wine sample, and formed creamy convex colonies with circular edge. Metschnikowia pulcherrima formed convex to pulvinate, circular white-pink colored colonies, Kloeckera apiculata formed flat, circular smooth colonies with turquoise center with gray edge, Pichia occidentalis formed irregular pulvinate light-cream colored colonies, and Pichia kluyveri formed turquoise, convex, undulate and smooth colonies on Malt extract agar base with bromocresol green.