ABSTRACT:Saccharomyces boulardii is unique probiotic and biotherapeutic yeast, known to survive in gastric acidity and it is not adversely affected or inhibited by antibiotics or does not alter or adversely affect the normal microbiota. S. boulardii has been utilized worldwide as a probiotic supplement to support gastrointestinal health. The multiple mechanisms of action of S. boulardii and its properties may explain its efficacy and beneficial effects in acute and chronic gastrointestinal diseases that have been confirmed by clinical trials. Caution should be taken in patients with risk factors for adverse events. Its potential application in various dairy foods could offer an alternative probiotic product to people suffering from antibiotic-associated diarrhea. This review discusses the evidence for efficacy and safety of S. boulardii as a probiotic for the prevention and therapy of gastrointestinal disorders in humans.

Listeria monocytogenes is ubiquitous in nature and a major concern for the food industry, since it is the causal agent of the serious foodborne illness listeriosis. This organism can be introduced through many routes to food-processing environments and may become established on food-processing equipment. Subsequently, food products may become contaminated during processing. In addition, the bacterium can grow at refrigeration temperatures. Biofilms are regarded as important with respect to the survival and growth of microorganisms in the food industry. Microorganisms growing in biofilms are protected against cleaning and disinfection and are difficult to eradicate. L. monocytogenes may grow in biofilms that protect them against environmental stress and can be isolated from surfaces after cleaning and disinfection. In this study, a total of eight L. monocytogenes strains isolated from the meat industry and one reference strain L. monocytogenes ATCC 19111 were studied for their capability to form a biofilm. The biofilm forming behavior of nine L. monocytogenes strains was determined in two different media, Tryptone soya yeast extract broth (TSYEB) or Brain-heart infusion broth (BHI), at temperatures 7 ºC, 25 ºC, 37 ºC, 42 ºC for 5 days. The method used to assess biofilm formation was crystal violet staining. All strains were able to form biofilm, but the growth condition affected the levels formed. The lowest biofilm formation was observed at 7 ºC. Further, the most effective medium in promoting biofilm production by the L. monocytogenes isolates from meat was BHI medium while for reference strain L. monocytogenes ATCC 19111 it was TSYEB. Incubation temperature was the most significant factor influencing the biofilm production levels, and also the type of used nutritive medium was important factor.

In the present study, the impact of synbiotic, compared to control treatment (CON), on growth performance and antioxidative status of broilers blood was investigated. The experiment was carried out on a total of 500 one-day-old broiler chickens of both sexes. The broilers were divided into two treatments with five replicates, based on a completely randomized design. The control treatment was fed basal diet, while experimental treatment was supplemented with synbiotic in addition of 1 g/kg of feed (SYN) in finisher period that lasted from 15 to 42 days of age. Diet supplementations with synbiotic led to increased body weight of broilers, compared to the control treatment. During the last 28 days, feed conversion ratio was significantly (P<0.05) improved in the synbiotic treatment (2.12), compared to the control treatment (2.21). The serum glutathione peroxidase, peroxidase, glutathione reductase and catalase activities were significantly higher (P<0.05), except of superoxide dismutase, in the supplemented treatment compared to the control treatment. Furthemore, there were noticed significant decreases (P<0.05) in malondialdehyde and glutathione content in the supplementary treatment. Based on the previously mentioned, it can be concluded that synbiotic can be applied as a growth promoter and as a natural antioxidant feed additive in broilers diet.

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.

Each category of pigs is susceptible to diseases caused by pathogenic bacteria, which negatively reflects on animal health, farm production results or meat quality. Animal feed is one of the potential reservoirs of pathogenic bacteria and infection source of domestic animals. Salmonella spp. is major microbiological hazard in animal feed. Thus, there is importance for implementation of strategies for preventing feed contamination with Salmonella, by minimizing dust, maximizing hygiene of space and processing equipment in feed mills and implementing control measures in each stage of feed production. Existing Salmonella feed contamination can be eliminated by conditioning and later different heat treatments (pelleting, extrusion, expansion) in production process while changing physical structure of the feed (coarsely or finely ground mash or pellets) can influence on conditions for Salmonella development in gastrointestinal tract of pigs. Contamination of feed by pathogenic bacteria and conditions for their development can be also controlled by addition of acidifiers, prebiotics, probiotics and, more recently, essential oils of plant origin, into feed. Various strategies for prevention of feed bacterial contamination, processes for feed decontamination, as well as possibilities for controlling pathogenic bacteria, especially Salmonella, in pig feed were presented and discussed in this article.