The inhibiting activity of three yeast strains belonging to Pichia kudriavzevii, Pichia occidentalis, and Meyerozyma quilliermondii/Meyerozyma caribbica genera against common plant pathogens representing Mucor spp., Penicillium chrysogenum, Penicillium expansum, Aspergillus flavus, Fusarium cereals, Fusarium poae, as well as Botrytis cinerea genera was investigated. The yeast strains tested had a positive impact on growth inhibition of all target plant pathogens. The degree of inhibition was more than 50% and varied depending on both the yeast antagonist and the mold. Ethyl esters of medium-chain fatty acids, phenylethyl alcohol, and its acetate ester prevailed among the analyzed volatile organic compounds (VOCs) emitted by yeasts in the presence of the target plant pathogens. Due to the method used, assuming no contact between the antagonist and the pathogen, the antagonistic activity of the yeast strains studied resulted mainly from the production of biologically active VOCs. Moreover, the antagonistic activity was not only restricted to a single plant pathogen but effective towards molds of different genera, making the yeast strains studied very useful for potential application in biological control.

The aim of this study was to obtain starter cultures for fermenting sweet pepper, pattypan squash and tomatoes, composed of the autochthonous lactic acid bacteria (LAB), selected from spontaneously fermented vegetables of each particular species. Antibacterial activity of the LAB strains against eight test strains of pathogenic and undesirable in food bacteria, as well as good organoleptic quality of obtained fermented product were adopted as selection criteria. Thirteen isolated LAB strains were identifi ed as Lactobacillus plantarum, Lactobacillus brevis and Pediococcus pentosaceus. All strains revealed the inhibiting capability, limiting the growth of at least two test strains. Ten selected LAB strains were used as starter cultures. Sensory quality of the obtained products was at least equal to the product obtained as a result of spontaneous fermentation. Using the autochthonous LAB strains of high antibacterial activity seems to be the rational way of producing microbiologically-safe products, preserving the original, unique fl avour of traditional, spontaneously fermented vegetables.

Introduction:One aim of the study was to evaluate the impact when added to feed of the two potentially probiotic strains of lactic acid bacteria (LAB) Lactobacillus plantarum K KKP 593/p and Lactobacillus rhamnosus KKP 825 on production performance, health, and the composition of gut microbiota. The complementary aim was to assess the safety of these strains in broiler rearing. Material and Methods: A total of 500 one-day-old Ross 308 chicks were divided into four groups. The experimental factor was the admixture of bacterial preparation to the feed at different doses: the recommended maximum dose, a dose ten times higher, the recommended minimum dose, and a zero dose for the control group not receiving bacteria. Results: Addition of bacteria to the diets did not have a significant effect on the final body weight, final body weight gain, nor total feed intake or feed conversion. However, lactic acid bacteria had a positive effect on chicken health. Mortality among chickens fed with LAB was reduced. Moreover, LAB feeding inhibited the growth of Salmonella spp. and Clostridium perfringens in the intestines. There were no significant differences in chicken performance by dose of bacteria in the feed. The group dosed with LAB ten times higher than the recommended maximum did not demonstrate changes in biochemical or haematological parameters of blood compared to the remaining groups. Conclusion: Feeding chicken broilers with two potentially probiotic LAB strains is safe and impacts animal health positively.

The aim of this work was to evaluate the activity of xenobiotic mixtures containing persistent organic pollutants isolated from commercial fish oil samples against sex hormone receptors, including estrogen and androgen. The applied bioassay was based on transgenic yeast strains. The mixtures were extracted from the samples using the semi-permeable membrane dialysis technique and analyzed with gas chromatography/ion trap mass spectrometry. It turned out that mixtures of chemicals isolated from fish oil may interact with human steroid sex hormone receptors in various ways: the tested samples showed both estrogenic and anti-androgenic activity. Calculated 17β-estradiol equivalents for the tested samples ranged between 0.003 and 0.073 pg g–1 (fat). Anti-androgenic activity expressed as the flutamide equivalent concentration was in the 18.58–216.21 ng g–1 (fat) range. Polychlorinated biphenyls and various DDT metabolites were the main fish oil pollutants influencing the receptors. Additivity and/or synergy between chemicals was observed in the ER/AR mediated response.