Toward rational selection criteria for selection of probiotics in pigs.

An accurate understanding of properties of probiotics is a prerequisite for selecting probiotic organisms for use in swine production. This review aims to review selection criteria for probiotic organism in swine. The systematically investigated ecological history rather than the source of isolates should be regarded as the natural origin of probiotic strains, which helps to correct the inconsistencies arising from incorrect identification of the source.

Metagenomic reconstructions of gut microbial metabolism in weanling pigs.

Background: The piglets' transition from milk to solid feed induces a succession of bacterial communities, enhancing the hosts' ability to harvest energy from dietary carbohydrates. To reconstruct microbial carbohydrate metabolism in weanling pigs, this study combined 16S rRNA gene sequencing (n = 191) and shotgun metagenomics (n = 72).

Results: Time and wheat content in feed explained most of the variation of the microbiota as assessed by 16S rRNA gene sequencing in weanling pigs.

Composition and Origin of the Fermentation Microbiota of Mahewu, a Zimbabwean Fermented Cereal Beverage.

Mahewu is a fermented cereal beverage produced in Zimbabwe. This study determined the composition and origin of mahewu microbiota. The microbiota of mahewu samples consisted of 3 to 7 dominant strains of lactobacilli and two strains of yeasts.

Pea polyphenolics and hydrolysis processing alter microbial community structure and early pathogen colonization in mice.

Health benefits associated with pea consumption have been attributed to the fiber and polyphenolic content concentrated within the pea seed coat. However, the amount of pea polyphenols can vary between cultivars, and it has yet to be studied whether pea polyphenols impact the intestinal microbiota. We hypothesized that pea polyphenols promote a healthy microbiome that supports intestinal integrity and pathogen colonization resistance.

Comparative assessment of qPCR enumeration methods that discriminate between live and dead Escherichia coli O157:H7 on beef.

Quantitative Polymerase Chain Reaction (qPCR) is a molecular method commonly used to detect and quantify bacterial DNA on food but is limited by its inability to distinguish between live and dead cell DNA. To overcome this obstacle, propidium monoazide (PMA) alone or with deoxycholate (DC) was used to prevent dead cell detection in qPCR. qPCR methods were used to detect strains of Escherichia coli O157, which can cause infection in humans with an infectious dose of less than 10 cells.

γ-Glutamyl Cysteine Ligase of Lactobacillus reuteri Synthesizes γ-Glutamyl Dipeptides in Sourdough.

Kokumi-active γ-glutamyl dipeptides (γ-GPs) accumulate in fermented food. γ-Glutamyl transferase, glutaminase, glutathione synthetase, and γ-glutamyl cysteine ligase (GCL) may synthesize γ-GPs. The genome of Lactobacillus reuteri encodes GCL but not glutathione synthetase or glutamyl transferase; therefore, this study investigated the role of GCL in γ-GP synthesis by L.

Challenges and opportunities related to the use of chitosan as a food preservative.

Chitosan has attracted a growing attention as a food preservative due to its versatility, nontoxicity, biodegradability and biocompatibility. This review aims to provide a critical appraisal of the limitations and opportunities of the use of chitosan as a food preservative. The application of chitosan as a food preservative necessitates insights into mechanisms of chitosan-mediated cell death and injury, factors affecting chitosan activity and effects of chitosan on food safety and quality.

Effect of chitosan, and bacteriocin - Producing Carnobacterium maltaromaticum on survival of Escherichia coli and Salmonella Typhimurium on beef.

The aim of this study was to investigate the synergistic effect of chitosan and bacteriocins against Escherichia coli and Salmonella in media and in lean beef. The inhibitory effects of chitosan and bacteriocins against E. coli AW1.

Metabolism of phenolic acids in whole wheat and rye malt sourdoughs.

This work aimed to study the phenolic acid metabolism of sourdough lactic acid bacteria (LAB) in laboratory media, and in sourdough fermentation with single cultures and in co-fermentations. Lactobacilli were selected from isolates obtained from 35 sourdough samples. Isolates (114 strains) were screened for phenolic acid decarboxylase gene pdc and EPS production.

Exploiting synergies of sourdough and antifungal organic acids to delay fungal spoilage of bread.

Fungal spoilage of bread remains an unsolved issue in bread making. This work aims to identify alternative strategies to conventional preservatives in order to prevent or delay fungal spoilage of bread. The minimum inhibitory concentration (MIC) of bacterial metabolites and chemical preservatives was evaluated in vitro, and compared to their in situ activity in baking trials.

Effect of Glutathione Dehydrogenase of Lactobacillus sanfranciscensis on Gluten Properties and Bread Volume in Type I Wheat Sourdough Bread.

Disulfide exchange reactions in wheat dough impact the polymerization of gluten and the volume of bread. In wheat sourdoughs fermented with Lactobacillus sanfranciscensis, glutathione reductase activity accumulates thiols. This study investigated the role of glutathione reductase and NADH oxidase of L.

Lifestyles of sourdough lactobacilli - Do they matter for microbial ecology and bread quality?

Sourdough is used in production of (steamed) bread as leavening agent (type I sourdoughs) or as baking improver to enhance flavour, texture, and shelf life of bread (type II sourdoughs). The long-term propagation of sourdoughs eliminates dispersal limitation and consistently leads to sourdough microbiota that are composed of host adapted lactobacilli. In contrast, community assembly in spontaneous cereal fermentations is limited by dispersal and nomadic or environmental lactic acid bacteria are the first colonizers of these sourdoughs.

Effect of temperature on production of oligosaccharides and dextran by Weissella cibaria 10 M.

The formation of HoPS and oligosaccharides in sourdough fermentation improves bread quality but is dependent on the expression of glycansucrases by lactic acid bacteria. Data on the expression of dextransucrases by Weissella spp., however, are limited.

Functional Analysis of Genes Comprising the Locus of Heat Resistance in Escherichia coli.

The locus of heat resistance (LHR) is a 15- to 19-kb genomic island conferring exceptional heat resistance to organisms in the family , including pathogenic strains of and The complement of LHR-comprising genes that is necessary for heat resistance and the stress-induced or growth-phase-induced expression of LHR-comprising genes are unknown. This study determined the contribution of the seven LHR-comprising genes , , , , , , and by comparing the heat resistances of strains harboring plasmid-encoded derivatives of the different LHRs in these genes. (Genes carry a subscript "GI" [genomic island] if an ortholog of the same gene is present in genomes of ) LHR-encoded heat shock proteins sHSP20, ClpK, and sHSP are not sufficient for the heat resistance phenotype; YfdX1, YfdX2, and HdeD are necessary to complement the LHR heat shock proteins and to impart a high level of resistance.

Effect of acceptor carbohydrates on oligosaccharide and polysaccharide synthesis by dextransucrase DsrM from Weissella cibaria.

The digestibility of isomalto-oligosaccharides (IMO) as well as their metabolism by gut microbiota depends on the degree of polymerization and the ratio of α-(1→4) to α-(1→6) linkages. Both parameters are influenced by the method of production. Commercial IMO are produced by transglycosylation of starch hydrolysates, or by transglycosylation with dextransucrase and sucrose as glucosyl-donor and maltose as glucosyl-acceptor.

Enzymatic Synthesis and Purification of Galactosylated Chitosan Oligosaccharides Reducing Adhesion of Enterotoxigenic Escherichia coli K88.

Enterotoxigenic Escherichia coli (ETEC) K88 causes diarrhea in weaned piglets and represent a suitable model system for ETEC causing childhood diarrhea. This study aimed to evaluate the effects of oligosaccharides against ETEC K88 adhesion to porcine erythrocytes with two bioassays. Galactosylated chitosan-oligosaccharides (Gal-COS) were synthesized through transgalactosylation by β-galactosidase.

Identification and quantification of virulence factors of enterotoxigenic Escherichia coli by high-resolution melting curve quantitative PCR.

Background: Diagnosis of enterotoxigenic E. coli (ETEC) associated diarrhea is complicated by the diversity of E.coli virulence factors.

Effect of Glutathione on the Taste and Texture of Type I Sourdough Bread.

Type I sourdough fermentations with Lactobacillus sanfranciscensis as predominant organism accumulate reduced glutathione through glutathione reductase (GshR) activity of L. sanfranciscensis. Reduced glutathione acts as chain terminator for gluten polymerization but is also kokumi-active and may thus enhance bread taste.

Some Like It Hot: Heat Resistance of in Food.

Heat treatment and cooking are common interventions for reducing the numbers of vegetative cells and eliminating pathogenic microorganisms in food. Current cooking method requires the internal temperature of beef patties to reach 71°C. However, some pathogenic such as the beef isolate AW 1.

Characterization of Linoleate 10-Hydratase of and Novel Antifungal Metabolites.

Lactobacilli convert linoleic acid to the antifungal compound 10-hydroxy-12-octadecenoic acid (10-HOE) by linoleate 10-hydratase (10-LAH). However, the effect of this conversion on cellular membrane physiology and properties of the cell surface have not been demonstrated. Moreover, produces 13-hydroxy-9-octadecenoic acid (13-HOE) in addition to 10-HOE, but the antifungal activity of 13-HOE was unknown.

Synthesis of Taste-Active γ-Glutamyl Dipeptides during Sourdough Fermentation by Lactobacillus reuteri.

This study aimed to assess whether peptides influence the taste of sourdough bread. γ-Glutamyl dipeptides with known kokumi taste threshold, namely γ-Glu-Glu, γ-Glu-Leu, γ-Glu-Ile, γ-Glu-Phe, γ-Glu-Met, and γ-Glu-Val, were identified in sourdough by liquid chromatography-tandem mass spectrometry in MRM mode. γ-Glutamyl dipeptides were found in higher concentrations in sourdough fermented with Lactobacillus reuteri when compared to the chemically acidified controls.

Site Directed Mutagenesis of Dextransucrase DsrM from Weissella cibaria: Transformation to a Reuteransucrase.

Glucansucrases produce α-glucans and gluco-oligosaccharides; the linkage type and molecular weight of glucans impacts their functionality. This study compared the catalytic specificities of dextransucrase DsrM from Weissella cibaria 10M and derivatives of this enzymes with GtfA from Lactobacillus reuteri TMW1.656.