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A serious global problem with the increasing resistance of microorganisms to currently used antimicrobials has opened up the promotional research in the identification of new, more effective drugs with a broad spectrum of antimicrobial activities. Plant essential oils, due to the large biological and structural diversity of their components, are known to have many potential benefits. This study aimed to evaluate the antimicrobial and anti-adhesion activity of fifteen essential oils and their compounds against two bacterial and two yeast species responsible for food spoilage and infectious diseases. Antimicrobial activity was determined by testing the minimum inhibitory concentration (MIC), the minimum bactericidal concentration (MBC) and the minimum fungicidal concentration (MFC) of essential oils and compounds. The essential oils of Cinnamomum zeylanicum and Eugenia caryophyllus showed the highest antimicrobial activity with MICs ranging from 0.078 to 1.25 mg/mL, and 0.039 to 1.25 mg/mL, respectively. On the other hand, essential oils of Eucalypti aetheroleum and Salvia officinalis had significantly weaker antimicrobial properties than the others. Further, MICs were used to assess the inhibition of adhesion of bacteria Salmonella Typhimurium ATCC 25923 and Staphylococcus aureus ATCC 14208, and yeasts Candida albicans ATCC 10231 and Saccharomyces cerevisiae ATCC 9763 in a microtiter plate using the crystal violet staining method. Based on the percentage of adhesion inhibition, yeast S. cerevisiae ATCC 9763 showed a high level of antimicrobial resistance. E. caryophyllus had the strongest effect with inhibition up to 73%. Consistent with the antimicrobial susceptibility results, the most active anti-adhesion compounds were carvacrol and thymol. Considering the role of biofilm in food spoilage and clinical diseases, inhibition of the initial phase of biofilm formation by natural antimicrobial agents may be an alternative to commonly used synthetic ones [ABSTRACT FROM AUTHOR]

The use of natural antifungal agents has gained much attention to extend shelf-life, increase the safety of food products in the food industry and inhibit disease-causing microorganisms. The objective of this study was to evaluate the antifungal and anti-adhesion potential of 15 plant extract, essential oils and chemical compounds against Candida spp. and Pichia spp. Susceptibility tests indicated that essential oils of Cinnamomum verum and Origanum vulgare had the highest inhibitory effect. For most extracts and essential oils examined, Pichia membranifaciens ZIM 2417 was the most sensitive yeast, while Candida glabrata ZIM 2369 proved to be the least sensitive one. Anti-adhesion ability of the plant extracts and essential oils against C. glabrata ZIM 2369 was estimated by the standard crystal violet assay. The results showed that the essential oils of C. verum, O.vulgare, Satureja montana and Thymus vulgaris possessed promising activity against the initial phase of biofilm formation and the pre-formed 24 h biofilm of C. glabrata. On the other hand, Sedum roseum extract showed the strongest anti-adhesion effect. Results of this study support the use of plant extracts, essential oils and their biologically active components against C. glabrata. [ABSTRACT FROM AUTHOR]

The aim of this study was to assess the potential of bacteria Escherichia coli ATCC 35218, Pseudomonas aeruginosa ATCC 27853, Staphylococcus aureus ATCC 25923 and yeast Pichia membranifaciens ZIM 2417 to adhere to wooden surfaces such as poplar (Populus sp.), Norway spruce (Picea abies), European beech (Fagus sylvatica), beech coated with the commercial Belinka oil food contact and disinfectant P3-oxonia active 150, and investigate their survival on the beech wood surface under different relative humidities (RH; 65%, 75%, 85%, 98%) and temperatures (10 °C, 20 °C, 27 °C/37 °C). To extend the research goals, the scanning electron microscopy (SEM) analysis was also performed. The adhesion was determined by the number of colony-forming units per mm2 of sample (CFU/mm2). Results showed that all tested bacteria and yeast were able to adhere to the wooden surfaces, although differences were observed according to strains and type of wood. It was evident that number of adhered cells of S. aureus was lower on spruce (3.62 × 103 CFU/mm2) compared to poplar and beech (1.09 × 105 and 2.11 × 104 CFU/mm2, respectively). Furthermore, oil and disinfectant promoted the adhesion of P. aeruginosa (155.93 and 130.50%, respectively) on the beech surfaces, while they had a strong inhibitory effect on the other tested microorganisms E. coli (87.44 and 88.44%, respectively), S. aureus (91.24 and 96.80%, respectively) and P. membranifaciens (92.45 and 87.24%, respectively). These findings are consistent with SEM micrographs. The current data also indicated that relative humidity and temperature significantly affected the adhesion of tested bacteria and yeast. The highest degree of adhesion was observed at a relative humidity of 98% and temperature of 20 and 37 °C for bacteria, or 20 and 27 °C for yeast. Thus, the knowledge of how these microorganisms adhere to wooden surfaces and which factors affect this phenomenon proves to be of great importance in order to avoid their colonization. [ABSTRACT FROM AUTHOR]

Food poisoning caused by Listeria monocytogenes leads to a 30% rate of mortality among patients. The application of essential oils (EOs) to food products is a suitable strategy to control pathogens and to extend their shelf life by reducing microbial levels. The objective of this study was to evaluate the antimicrobial potential of essential oils (EOs) against L. monocytogenes. The EOs used in this study were caraway (Carum carvi), cinnamon (Cinnamomum zeylanicum), dill (Anethum graveolens), clove (Syzygium aromaticum), mentha (Menthae piperitae aetheroleum), red thyme (Thymus vulgaris), rosemary (Rosmarinus officinalis), common sage (Salvia officinalis), clary sage (Salvia sclarea) and summer savory (Satureja hortensis). The minimal inhibitory concentrations (MICs) of EOs were determined using the broth microdilution method. According to the MIC values, all essential oils were effective in the inhibition of L. monocytogenes strains, with MICs varying from 256 μg/ml to 4096 μg/ml. The results showed that cinnamon EO had the highest antimicrobial activity, while dill and mentha EOs were the least effective against the L. monocytogenes. In addition, two different procedures were carried out to test the effect of antibiotics gentamycin and streptomycin against the L. monocytogenes strains, the broth microdilution method and the MIC Test Strip. Our results indicated that the reference strain L. monocytogenes ATCC 19111 was much more sensitive to antibiotics than L. monocytogenes strains isolated from meat, highlighting that gentamycin was the more effective in comparison to streptomycin. [ABSTRACT FROM AUTHOR]

An understanding of adhesion behavior of Candida and Pichia yeast under different environmental conditions is key to the development of effective preventive measures against biofilm-associated infection. Hence in this study we investigated the impact of growth medium and temperature on Candida and Pichia adherence using stainless steel (AISI 304) discs with different degrees of surface roughness (Ra = 25.20–961.9 nm), material typical for the food processing industry as well as medical devices. The adhesion of the yeast strains to stainless steel surfaces grown in Malt Extract broth (MEB) or YPD broth at three temperatures (7 °C, 37 °C, 43 °C for Candida strains and 7 °C, 27 °C, 32 °C for Pichia strains) was assessed by crystal violet staining. The results showed that the nutrient content of medium significantly influenced the quantity of adhered cells by the tested yeasts. Adhesion of C. albicans and C. glabrata on stainless steel surfaces were significantly higher in MEB, whereas for C. parapsilosis and C. krusei it was YPD broth. In the case with P. pijperi and P. membranifaciens , YPD broth was more effective in promoting adhesion than MEB. On the other hand, our data indicated that temperature is a very important factor which considerably affects the adhesion of these yeast. There was also significant difference in cell adhesion on all types of stainless steel surfaces for all tested yeast. [ABSTRACT FROM AUTHOR]

The use of natural substances with antimicrobial activity in combination with conventional antimicrobial agents is a promising strategy in the control of pathogenic bacteria. The aim of this study was to examine the antimicrobial activity of a disinfectant based on sodium hypochlorite and lavender, tea tree, peppermint and rosemary essential oils against Gram-positive (Bacillus cereus ATCC 11778, Staphylococcus epidermidis ATCC 12228) and Gram-negative (Pseudomonas aeruginosa ATCC 10145, Salmonella Typhimurium ATCC 14028) bacteria. Further, to evaluate the antimicrobial activity of essential oils and the disinfectant mixed in various combinations in order to detect synergistic or antagonistic effects and discuss these effects on the basis of an improved checkerboard technique. The results showed a synergistic and additive effect for most combinations of the disinfectant and essential oils with fractional inhibitory concentrations index (FICI) values of 0.375 and 1, respectively. The effectiveness of the disinfectant in combination with essential oils was also determined using the quantitative suspension test and results indicated the maximum germicidal effect after the exposure time of 5 min. Taking into account increased interest in the use of natural antimicrobial agents in recent years, the application of a combination of disinfectant with essential oils represents a significant strategy in the control of pathogenic bacteria. [ABSTRACT FROM AUTHOR]

The quality of protein is based on their amino acid composition, especially on the content and availability of essential amino acids. Cereals are important sources of protein for human nutrition, but are limited in the amounts of essential amino acids, notably lysine. The aim of this study was to analyze the chemical composition and amino acid profiles of different cereals that are important for nutritional purposes in human diet. The content of protein, moisture and crude fat in cereals varied significantly from 7.83 to 13.22%, 11.45 to 13.80%, and from 1.67 to 6.35%, respectively. The obtained results showed that oat had the highest contents of crude protein (13.22%), crude fat (6.35%) and crude cellulose (9.42%) compared to other cereals. Significant (p < 0.05) variation existed in the content of essential and nonessential amino acids among samples with the highest level in oat and wheat. Essential amino acids accounted for one-third of the total amino acids in the tested cereals. Glutamic acid was found to be the most abundant amino acid. It could be concluded that the amino acid composition of oat is the most favorable among cereals due to its high protein content and the content of lysine which can be found in limited amounts in most of the cereals. [ABSTRACT FROM AUTHOR]

A global increase in the demand for livestock products suggests that there will be a consequent rise in demand for feed, not only of cereals but of other feeds and particularly proteins. In the present study, oil industry by-products such as soybean meal, soybean cake and sunflower meal were analysed as sources of amino acids in animal nutrition. From among oilseed byproducts, the soybean meal content the most of crude protein up to 44% and the best of amino acid composition, while content of crude cellulose (about 6%) is lower in comparison to other oilseed meals. The results showed that the total amino acids in the examined samples ranged from 31.87 to 41.01%, and the total essential and nonessential amino acids varied from 13.41 to 17.38% and from 18.46 to 23.76%, respectively. Generally, the protein contained in soybean meal and cake was rich in essential amino acids. However, because of the lowest amino acid score, methionine was considered as a limiting amino acid in both soybean by-products. On the other hand, soya's meal contained higher level of lysine than other protein-based vegetable alternative to soya like sunflower meals examined in this study. Glutamic acid, aspartic acid, leucine and valine were the most abundant amino acids in all tested by-products of the oil industry. Therefore, partial substitution of protein sources in feeds with proteins from the oil industry by-products may improve feed quality. [ABSTRACT FROM AUTHOR]