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BACKGROUND During the manufacture of sucrose from sugar beet, different microorganisms originating from the plant material as well as from the soil enter the process. Due to the formation of polysaccharide-based slimes, these contaminants may induce several adverse effects such as filtration problems during juice purification. Certain microorganisms also metabolize sucrose, leading to product losses with financial consequences. To better understand and to prevent these negative effects, the aim of the study was to investigate the evolution of relevant bacterial groups, including their metabolites appearing during the extraction process. For this purpose, one production cycle was monitored to identify the major contamination steps and to clarify how they relate to the processing conditions. Traditionally, different antimicrobial agents such as formaldehyde, sulfur dioxide, hypochlorous acid, sodium hypochlorite, and chlorine dioxide have been added to inhibit microbial growth. In the present study, a rosin-based product derived from pine trees was applied as an alternative to those substances. RESULTS Press water, raw juice, and mid-tower juice were identified as being highly contaminated with bacteria, and processing conditions such as time, temperature and pH level significantly influenced bacterial levels and the corresponding metabolites. Among the contaminants identified, lactic acid bacteria, and mesophilic and thermophilic aerobic bacteria played a dominant role, whereas lactic acid, acetic acid, butyric acid, and ethanol were identified as typical metabolites. CONCLUSION Bacterial growth during production could be reduced by shock dosing of the rosin-based material in the extraction area. © 2020 Society of Chemical Industry.

Cronobacter spp. are opportunistic human pathogens that cause serious diseases in neonates and immunocompromised people. Owing to their biofilm formation on various surfaces, both their detection and their removal from production plants constitute a major challenge. In this study, food samples were randomly collected in Austria and examined for the presence of Cronobacter spp. Presumptive isolates were identified by a polyphasic approach. Five percent of the samples were positive for C. sakazakii and 2.4% for C. dublinensis. Individual growth of the isolates was characterized based on lag time, growth rate, and generation time. During an incubation period of 6 to 72 h, biofilm formation of 11 selected isolates was quantified under model conditions by a crystal violet staining assay with 96-well plates with different carbon sources (lactose, glucose, maltose, sucrose, and sodium acetate) and NaCl levels and under variable temperature and pH conditions. Biofilm formation was more pronounced at lactose concentrations between 0.25 and 3% compared with 5% lactose, which lead to thinner layers. C. sakazakii isolate C7, isolated from infant milk powder, was the strongest biofilm producer at 10 mM Mg2+ and 5 mM Mn2+, 0.5% sodium acetate, at pH levels between 7 and 9 at 37°C for 24 h. C. sakazakii strain C6 isolated from a plant air filter was identified as a moderate biofilm former and C. sakazakii strain DSM 4485, a clinical isolate, as a weak biofilm former. Based on PCR detection, genes bcsA, bcsB, and bcsG encoding for cellulose could be identified as markers for biofilm formation. Isolates carrying bcsA and bcsB showed significantly stronger biofilm formation than isolates without these genes ( P < 0.05), in strong correlation with the results obtained in the crystal violet assay. Further investigations using confocal laser scanning microscopy revealed that extracellular polymeric substances and glycocalyx secretions were the dominating components of the biofilms and that the viable fraction of bacteria in the biofilm decreased over time.

In this study, the influence of meat batter composition and sausage diameter on the development of microbiota and sensory traits of traditional, spontaneously fermented wild boar meat sausages are evaluated. This research also demonstrates how principal component analysis (PCA) can be used to relate product sensory properties to particular microbial genotype and to select potential starter or adjunct culture. Generally, similar microbiological results were obtained in all types of products. The undesirable microbiota was either not detected at any sausage production stage or its number decreased below the detection limit in ripened sausages. The low growth rate of lactic acid bacteria (LAB) was consistent with the obtained pH and slow acidification rate. Although no differences in the composition of LAB species were noticed between sausage types (50S=50 % wild boar meat in small casing, 50L=50 % wild boar meat in large casing, 100S=100 % wild boar meat in small casing), a clear separation based on LAB genotypes could be observed. Upon quantitative descriptive analysis, significant differences in sensory attributes between sausage types were established. According to the PCA, the overall acceptability traits of sausages are closely linked to one Leuconostoc mesenteroides genotype (LM_4). Of all tested technological properties, LM_4 strains showed remarkable acidification ability, lowering the pH from pH=5.41 to 3.74, and pronounced proteolytic activity on skimmed milk as well as antagonistic activity against Staphylococcus aureus (DSM 20231) and Brochothrix thermosphacta (LMG 17208). Lipolytic and haemolytic activities were not detected, and all analyzed strains were susceptible to tested antibiotics and possessed no biogenic amine genes.

Food fermentation technologies have developed through years of experience rather than scientific findings. Therefore, many small-scale manufacturers are unwilling to accept changes and to modify fermentation processes. Still, traditional fermented foods have had an essential role in human nutrition for thousands of years. A wide range of diverse cereals, legumes, vegetables, fruits, fish, seafood, and meat are used as raw materials for the production of these fermented foods by back-slopping (a process where material from a previous successful batch is added to facilitate the initiation of a new batch) or naturally occurring microorganisms. Various microorganisms that influence the quality, safety, sensory properties, acceptability, and consistency of these products are present. Lactic acid bacteria with their beneficial characteristics are generally a significant contributor. Identification and profiling of microorganisms in fermented foods are of particular interest. But so far such information has not been explored in detail for some fermented products from the lower Mekong subregion. Improving the safety, quality, and acceptability of fermented foods, while reducing their production costs and maintaining their authenticity and uniqueness, is important. This can be achieved through starter culture application and greater attention to food safety, such as HACCP approaches. Recent scientific advances have led to the development of defined microbial starters, leading to the transfer of artisanal food production to more controlled and industrialized fermentation. The aim of this review is to determine the gaps in the knowledge of traditional fermented foods of the lower Mekong subregion and to present current information on the diversity of involved microorganisms. These data will be helpful for defining future strategies toward the sustainable production of safe fermented foods particularly those from southeast Asia.

In the present study, we isolated and screened thirty strains of GABA (&gamma, aminobutyric acid)-producing lactic acid bacteria (LAB) from traditional Indonesian fermented foods. Two strains were able to convert monosodium glutamate (MSG) to GABA after 24 h of cultivation at 37 &deg, C based on thin layer chromatography (TLC) screening. Proteomic identification and 16S rDNA sequencing using MALDI-TOF MS identified the strain as Lactobacillus plantarum designated as L. plantarum FNCC 260 and FNCC 343. The highest yield of GABA production obtained from the fermentation of L. plantarum FNCC 260 was 809.2 mg/L of culture medium after 60 h of cultivation. The supplementation of 0.6 mM pyridoxal 5&rsquo, phosphate (PLP) and 0.1 mM pyridoxine led to the increase in GABA production to 945.3 mg/L and 969.5 mg/L, respectively. The highest GABA production of 1226.5 mg/L of the culture medium was obtained with 100 mM initial concentration of MSG added in the cultivation medium. The open reading frame (ORF) of 1410 bp of the gadB gene from L. plantarum FNCC 260 encodes 469 amino acids with a calculated molecular mass of 53.57 kDa. The production of GABA via enzymatic conversion of monosodium glutamate (MSG) using purified recombinant glutamate decarboxylase (GAD) from L. plantarum FNCC 260 expressed in Escherichia coli was found to be more efficient (5-fold higher within 6 h) than the production obtained from fermentation. L. plantarum FNCC 260 could be of interest for the synthesis of GABA.

In the present study, we isolated and screened thirty strains of GABA-producing lactic acid bacteria (LAB) from Indonesian traditional fermented foods. Two strains were able to convert monosodium glutamate (MSG) to GABA after 24 h of cultivation at 37oC based on thin layer chromatography (TLC) screening. 16S rDNA sequencing and proteomic identification using MALDI-TOF MS identified these two strains as Lactobacillus plantarum designated as L. plantarum FNCC 260 and L. plantarum FNCC 343. The highest yield of GABA production obtained from the fermentation of L. plantarum FNCC 260 was 809.2 mg/l of culture medium after 60 h of cultivation. Supplementation of 0.6 mM pyridoxal 5’-phosphate (PLP) and 0.1 mM pyridoxine led to the increase in GABA production to 945.3 mg/l and 969.5 mg/l, respectively. The highest GABA production of 1226.5 mg/l of culture medium was obtained with 100 mM initial concentration of MSG added in the cultivation medium. The open reading frame (ORF) of 1410 bp of the gadB gene from L. plantarum FNCC 260 encodes 469 amino acids with a calculated molecular mass of 53.57 kDa. The production of GABA via enzymatic conversion of monosodium glutamate (MSG) using purified recombinant glutamate decarboxylase (GAD) from L. plantarum FNCC 260 expressed in Escherichia coli was found to be more efficient (5-fold higher within 6 h) than the production obtained from fermentation. L. plantarum FNCC 260 could be of interest for the synthesis of GABA.

Clostridium tyrobutyricum, a Gram-positive, anaerobic, spore-forming bacterium, is considered as one of the main causative agents for spoilage of hard and semihard cheeses. Growth of C. tyrobutyricum in cheese is critically influenced by ripening temperature and time, pH, salt and lactic acid concentration, moisture and fat content, and the presence of other microorganisms. Previous studies revealed high intraspecies diversity of C. tyrobutyricum strains and variable tolerance toward pH, temperatures, and salt concentrations. These findings indicate that strain-dependent characteristics may be relevant to assess the risk for cheese spoilage if clostridial contamination occurs. In this study, we aimed to compare the phenotypes of 12 C. tyrobutyricum strains which were selected from 157 strains on the basis of genotypic and proteotypic variability. The phenotypic analysis comprised the assessment of gas production and organic acid concentrations in an experimental cheese broth incubated at different temperatures (37, 20, and 14 &deg, C). For all tested strains, delayed gas production at lower incubation temperatures and a strong correlation between gas production and the change in organic acid concentrations were observed. However, considering the time until gas production was visible at different incubation temperatures, a high degree of heterogeneity was found among the tested strains. In addition, variation among replicates of the same strain and differences due to different inoculum levels became evident. This study shows, that, among other factors, strain-specific germination and growth characteristics should be considered to evaluate the risk of cheese spoilage by C. tyrobutyricum.

Preventing food spoilage without the addition of chemical food additives, while increasing functional properties of wheat-based bakery products, is an increasing demand by the consumers and a challenge for the food industry. Within this study, lactic acid bacteria (LAB) isolated from sourdough were screened in vitro for the ability to utilize the typical wheat carbohydrates, for their antimicrobial and functional properties. The dual culture overlay assay revealed varying levels of inhibition against the examined fungi, with Lactiplantibacillus plantarum S4.2 and Lentilactobacillusparabuchneri S2.9 exhibiting the highest suppression against the indicator strains Fusarium graminearum MUCL43764, Aspergillus fumigatus, A. flavus MUCL11945, A. brasiliensis DSM1988, and Penicillium roqueforti DSM1079. Furthermore, the antifungal activity was shown to be attributed mainly to the activity of acids produced by LAB. The antibacillus activity was evaluated by the spot-on-the-lawn method revealing a high inhibition potential of the majority of LAB isolated from sourdough against Bacillus cereus DSM31, B. licheniformis DSM13, B. subtilis LMG7135, and B. subtilis S15.20. Furthermore, evaluating the presence of the glutamate decarboxylase gen in LAB isolates by means of PCR showed a strain dependency of a potential GABA production. Finally, due to improved functional activities, LAB isolated from sourdoughs exhibit promising characteristics for the application as natural preservatives in wheat-based bakery products.

The quantification of nitrate and nitrite in molasses is an emerging requirement for the sugar industry. The establishment of a validated analytical methodology is necessary to comply with the EU-guidelines on maximum permissible levels currently under discussion. In the present study, validation of an anion exchange chromatographic method to determine nitrate and nitrite in molasses was performed determining key validation parameters via several stages of an interlaboratory comparison for the first time. Since a stable, homogeneous sample material was necessary for establishing quantitative accuracy, a nitrite-spiked molasses material was prepared and evaluated independently across two laboratories in a parallel study. This preliminary study revealed that quantification of nitrate and nitrite content in molasses could be achieved with excellent precision under repeatability conditions of measurement (1.21% RSD for nitrate; 1.26% RSD for nitrite) in independent laboratories but requires preservation of samples at −20 °C for long-term (>several days) storage prior the analysis. A subsequent stage involving five different participating laboratories was then undertaken to evaluate anion exchange chromatography with conductivity detection for this application within a round robin study. The first phase focused on the analysis of nitrite-spiked molasses to optimize the individual analytical practices of laboratories and to elaborate a harmonized sample preparation protocol. In the second phase the participating laboratories analyzed seven molasses samples with different pH-value, dry substance, factory origin, with nitrate levels ranging from 2931 mg/kg – 6436 mg/kg and nitrite levels ranging from 25.3 mg/kg – 109 mg/kg. The determination of precision of reproducibility conditions of measurement revealed average relative interlaboratory standard deviations of 2.5% for nitrate and of 13% for nitrite. The present study clearly demonstrates the necessity of harmonization and standardization regarding measurement and data evaluation procedures applied for controlling nitrate and nitrite in molasses.

Short-chain cello-oligosaccharides (COS; degree of polymerization, DP≤6) are promising water-soluble dietary fibers. An efficient approach to their bottom-up synthesis is from sucrose and glucose using glycoside phosphorylases. Here, we show intensification and scale up (20 mL; gram scale) of COS production to 93 g/L product and in 82 mol % yield from sucrose (0.5 M). The COS were comprised of DP 3 (33 wt %), DP 4 (34 wt %), DP 5 (24 wt %) and DP 6 (9 wt %) and involved minimum loss (≤10 mol %) to insoluble fractions. After isolation (≥95% purity; ≥90% yield), the COS were examined for growth promotion of probiotic strains. Benchmarked against inulin, trans-galacto-oligosaccharides and cellobiose, COS showed up to 4.1-fold stimulation of cell density forClostridium butyricum,Lactococcus lactissubsp.lactis,Lactobacillus paracaseisubsp.paracaseiandLb. rhamnosusbut were less efficient withBifidobacteriumsp. This study shows the COS as selectively functional carbohydrates with prebiotic potential and demonstrates their efficient enzymatic production.

Screening for various types of lactic acid bacteria (LAB) that form the biological agent &gamma, amino-butyric acid (GABA) is important to produce different kinds of GABA-containing fermented foods. So far, no GABA-producing LAB have been reported from Cambodian fermented foods. Most small-scale fermentations and even some industrial processes in this country still rely on indigenous LAB. The application of GABA-producing autochthonous starters would allow the production of Cambodian fermented foods with an additional nutritional value that meet the population&rsquo, s dietary habits and that are also more attractive for the international food market. Matrix-assisted laser desorption/ionizing time-of-flight mass spectrometry (MALDI-TOF MS) and partial 16S rDNA sequencing were used to identify 68 LAB isolates from Cambodian fermented foods. These isolates were classified and grouped with (GTG)5 rep-PCR, resulting in 50 strains. Subsequently, all strains were investigated for their ability to produce GABA by thin layer chromatography. GABA-positive strains were further analyzed by the GABase assay. Of the six GABA-positive LAB strains&mdash, one Lactobacillus futsaii, two Lactobacillus namurensis, and three Lactobacillus plantarum strains&mdash, two Lactobacillus plantarum strains produced high amounts of GABA (20.34 mM, 16.47 mM). These strains should be further investigated for their potential application as GABA-producing starter cultures in the food applications.

The aim of this investigation was to determine the influence of seven different Lactobacillus spp. (Lb.) strains compared with a commercial starter culture (CS) on the functional properties of gluten-free (GF) sourdough-breads. The sourdough stability of selected strains was also evaluated upon back-slopping. Results showed that the bread properties were greatly affected by the Lb. strains. Millet breads achieved lower specific volumes (1.80–2.19 cm3/g), higher crumb firmness (19.01–42.19 N) and lower relative elasticities (21.5–43.4%) than buckwheat breads. Compared with the CS, Lactobacillus pentosus and Lb. hammesii positively influenced the crumb firmness of buckwheat and millet breads, respectively, while Lb. paralimentarius enhanced this property in both breads. Only one of the two Lactobacillus sanfranciscencis strains was able to improve all functional properties in both GF breads. Back-slopping of the sourdoughs revealed stable properties in case of buckwheat, while maturity of the millet sourdough could not be reached. These observations were supported by the microbial count, metabolite production and carbohydrate consumption. Mature sourdough significantly improved the crumb firmness and porosity of the GF breads. These results highlighted the importance of selecting the appropriate lactic acid bacteria strains, to maximize the quality of GF bread.

Lactic acid bacteria (LAB) from spontaneous rye sourdough were isolated, identified, and characterized by their growth, acidification rate, and carbohydrate metabolism. The isolated LAB were used for production of rye sourdough, and the influence of sourdough on mixed rye - wheat bread quality and acrylamide formation was evaluated. In addition, comparative studies by using acidification with L-(+)-lactic acid for mixed rye – wheat bread production were performed. Isolated LAB (P. acidilactici, L. plantarum, L. curvatus) demonstrated versatile carbohydrate metabolism, grown at 30 °C and 37 °C, and acidic tolerance. When the isolated strains were used for rye sourdough production, they showed good growth, acidification rates while excreting amylolytic and proteolytic enzymes. Rye sourdoughs delay bread staling, and there was a significant effect of type of dough acidification (with LAB or L-(+)-lactic acid) and the quantity of acidification agent used (5% or 15%) on most of the analyzed bread quality parameters. L. plantarum sourdough (added in the amount of 5% and 15%) decreased the acrylamide content in bread samples (p

Objective: The aim of this study was to investigate the bacterial bioburden in experimental in vitro wounds during the application of conventional negative pressure wound therapy (NPWT), with and without antimicrobial dressings (polyhexanide, silver), against NPWT instillation of octenidine. Method: Experimental wounds produced in an in vitro porcine wound model were homogenously contaminated with bacterial suspension and treated with NPWT and different options. Group A: non-antimicrobial polyurethane foam dressing; group B: antimicrobial polyurethane foam dressing containing silver; group C: antimicrobial gauze dressing containing polyhexanide; group D: non-antimicrobial polyurethane foam dressing intermittently irrigated with octenidine; group E: negative control (non-antimicrobial polyurethane foam dressing without NPWT). Standard biopsies were harvested after 24 and 28 hours. Results: This study demonstrated that the use of NPWT with intermitted instillation of octenidine (group D) or application of silver-based polyurethane foam dressings (group B) is significantly superior against Staphylococcus aureus colonisation in experimental wounds compared with non-antimicrobial polyurethane foam dressing (group A) after 48 hours. Surprisingly, the polyhexanide-based dressing (group C) used in this model showed no statistical significant effect compared with the control group (group E) after 24 or 48 hours of treatment. Conclusion: Both intermitted instillation of octenidine and silver-based dressings in standard NPWT were significantly superior compared with non-antimicrobial polyurethane foam dressings or PHMB coated gauze dressing after 48 hours.

A Lactobacillus plantarum strain was used for the production of rye, wheat, barley, and oat sourdoughs, and the influence of different sourdoughs on mixed rye–wheat bread quality parameters and acrylamide formation was evaluated. L. plantarum LUHS135 demonstrated versatile carbohydrate metabolism, good growth and acidification rates, and the ability to excrete amylolytic and proteolytic enzymes in various cereal sourdoughs. The same starter and different cereal substrates allow to produce sourdoughs showing different characteristics. The type of sourdough and its quantity had significant influence on acrylamide content in bread (P ≤ 0.0001), and using 5% or 10% of wheat sourdough, 5%, 15%, or 20% of barley sourdough, and 5% or 15% of oat sourdough, it is possible to reduce acrylamide content in bread. Thus, manufacturers need to take into account application of apparent technological approaches for acrylamide in bread reducing.

Via butyric acid fermentation, clostridia – mainly Clostridium tyrobutyricum – are able to transform lactic acid into butyric acid, acetic acid and gas (H2 and CO2). The presence of clostridial endospores in milk may lead to severe quality defects in semi-hard and hard cheeses. As a consequence of butyric acid fermentation during ripening, cheeses tend to swell and develop undesired slits, irregular eyes and a rancid taste, thus resulting in high economic losses for producers. Several measures regarding stable, milking and feed hygiene have already been partly implemented to minimise the risk of raw milk contamination with clostridial endospores. Contamination, nevertheless, cannot be avoided completely. Moreover, some of the existing procedures to reduce the bacterial and endospore count in milk (e.g. bactofugation, addition of bacteriocins) are not always applicable or even prohibited for the production of certain cheese types. Therefore, cheese producers may benefit from integrating the determination of the initial count of clostridial endospores in milk into their quality control system of primary materials. This review discusses the role of butyric acid clostridia in the cheese processing environment and methods for the detection and enumeration of cheese-damaging clostridia in milk and cheese.

Sourdough processing contributes to better digestible wheat-based bakery products, especially due to the proteolytic activity of lactic acid bacteria (LAB). Therefore, sourdough-related LAB were screened for their capacity to degrade immunogenic proteins like gluten and alpha-amylase-trypsin inhibitors (ATIs). Firstly, the growth of 87 isolates was evaluated on a gluten-based medium. Further, the breakdown capacity of selected isolates was determined for gluten with a focus on gliadins by measuring acidification parameters and MALDI-TOF MS protein profiles. ATI degradation after 72 h of incubation within an ATI-based medium was investigated by means of acidification, HPLC, and competitive ELISA. All isolates exhibited the potential to degrade ATIs to a high degree, whereas the gliadin degradation capacity varied more greatly among tested LAB, with Lacticaseibacillus paracasei Lpa4 exhibiting the strongest alterations of the gliadin pattern, followed by Lactiplantibacillus plantarum Lpl5. ATI degradation capacities ranged from 52.3% to 85.0% by HPLC and 22.2% to 70.2% by ELISA, with Lacticaseibacillus paracasei Lpa4 showing superior breakdown properties. Hence, a selection of specific starter cultures can be used in sourdough processing for wheat-based bakery products with reduced gluten and ATI content and, further, better tolerated products for patients suffering from non-celiac wheat sensitivity (NCWS).

In sourdough processing, lactic acid bacteria (LAB) and yeasts are responsible for the bread's unique characteristics. To evaluate the microbial ecology of traditional Austrian sourdoughs, 11 wheat and nine rye sourdoughs were examined. The colony counts of the LAB ranged from

Late-blowing – severe cheese spoilage caused by clostridia – is a long-standing problem of economic importance for dairy processors. However, there is still a paucity of relevant data on clostridia in cheese that would allow some tailored intervention. The main aim of this study was to identify and quantify clostridia in late-blown cheese using a polyphasic methodological approach. Fifty-three cheeses of different origins were analysed using culture-dependent (MPN, enrichment, molecular identification of isolates) and culture-independent methods (real-time PCR, PCR-DGGE and Illumina 16S rDNA sequencing). Using culture-dependent methods, clostridial isolates were collected from several cheese samples, while fewer positive results were obtained with the samples when using the MPN procedure than real-time PCR or PCR-DGGE. In contrast to other studies, an extremely low diversity of Clostridium species was observed. Surprisingly, Illumina 16S rDNA amplicon sequencing revealed relative abundances of clostridia below the detection limit despite apparent cheese spoilage.

Spontaneously fermented wild boar and deer meat sausages produced in Croatia were physicochemically and microbiologically investigated at different time points of their production. Final products resulted with pH and aw values between 5.04–5.53 and 0.83–0.87, respectively. The histamine concentration was below 5.0 mg/kg whereas tyramine content ranged from 47.3 to 219.0 mg/kg. A total of 917 isolated lactic acid bacteria (LAB) were genotyped by rep-PCR and identified by 16S rRNA gene sequencing. Overall, Leuconostoc mesenteroides was identified as the most frequently isolated species (n = 259), followed by Lactobacillus sakei (n = 190) and Enterococcus casseliflavus (n = 106). Cluster analysis revealed a remarkable intraspecies diversity and a strong sausage-specific clustering of the LAB genotypes, indicating meat as a probable source of microbial diversity in sausages. 14.38% of LAB were positive for tyramine encoding gene and no other target biogenic amines genes were detected. Due to the elevated number of presumptive pathogens (E. coli. Enterobacteriaceae, B. cereus group, coliforms) in ready-to-eat sausages, 33.33% of products can be considered as inappropriate for human consumption.

A pig digestibility trial was conducted to investigate the effects of fermentation or extrusion of wheat bran included in a basal diet on coefficients of total tract apparent digestibility (CTTAD) regarding dry matter (DM), organic matter (OM), crude protein (CP), crude fiber (CF), ether extract (EE), starch, energy (GE), phosphorus (P) and calcium (Ca). In the experiment, 9 growing pigs were allocated to a 3 × 3 Latin square design to measure the CTTAD of the basal diet containing different modified wheat bran variants, and therefore to demonstrate relative differences in the CTTAD among the diets as a result of wheat bran modification. The wheat bran was used in native form (NWB), as fermented bran ensiled with Lactobacillus paracasei and Lactobacillus plantarum (FWB) and as extruded wheat bran (EWB). Wheat bran variants were included at 200 g kg −1 in a phosphorus deficient basal diet. The obtained results show that the CTTAD of DM was increased when feeding the diet with FWB (+2%, P P P P P P P P P P P

Biopreservation is a powerful and natural tool to extend shelf life and to enhance the safety of foods by applying naturally occurring microorganisms and/or their inherent antibacterial compounds of defined quality and at certain quantities. In this context, lactic acid bacteria (LAB) possess a major potential for use in biopreservation because most LAB are generally recognized as safe, and they naturally dominate the microflora of many foods. The antagonistic and inhibitory properties of LAB are due to different factors such as the competition for nutrients and the production of one or more antimicrobially active metabolites such as organic acids (prevailingly lactic and acetic acid), hydrogen peroxide, and antimicrobial peptides (bacteriocins). This review addresses various aspects related to the biological preservation of seafood and seafood products by LAB and their metabolites.

This study aimed to investigate the specific growth stimulation of certain desired intestinal bacteria by a novel galacto-oligosaccharide mixture, which was produced with a &beta, galactosidase from a potential probiotic Lactobacillus isolate that contained mainly oligosaccharides of &beta, 1,3 and &beta, 1,6 glycosidic linkages (termed Lb-GOS) using single-strain fermentations. The composition of this Lb-GOS mixture was 33.5% disaccharides, 60.5% trisaccharides, 4.8% tetrasaccharides, and 1.0% pentasaccharides with a negligible amount of monosaccharides, lactose, and lactobionic acid (0.3%). Eight Lactobacillus spp. strains and three Bifidobacterium spp. strains were used in single-strain fermentations to determine the fermentation activity scores of this Lb-GOS preparation compared to two commercially available prebiotic mixtures, 4&prime, GOS-P and Vivinal GOS (V-GOS). The highest scores were obtained when L. reuteri Lb46 and the two Bifidobacterium strains, B. animalis subsp. lactis Bif1 and Bif3, were grown on these galacto-oligosaccharide mixtures. In addition, the Lb-GOS mixture was found to have higher fermentation activity scores, hence, it stimulated the growth of these probiotic strains more than 4&prime, GOS-P and V-GOS, which may be attributed to the different glycosidic linkage types that are found in the Lb-GOS mixture compared to the other two commercial preparations. These findings suggested that the Lb-GOS mixture that is described in this work should be of interest for the formulations of new carbohydrate-based functional food ingredients.

Lactic acid bacteria (LAB) play a dual role in winemaking as they are the main effectors of malolactic fermentation, but some members can also cause wine spoilage. PCR-DGGE has proved to be a quick tool to study the LAB community and their fluctuation in wine. For detecting wine-associated LAB by PCR-DGGE, the primer sets WLAB1/WLAB2GC, WBAC1/WBAC2GC, Lac1/Lac1o/Lac2GC, 341fGC/518r and rpoB1/rpoB1o/rpoB2GC were tested and evaluated in this study. The primer systems were assessed by the separation of LAB reference strains on DGGE gels and by attributing the resulting amplicons to defined species. Subsequently, the detection of LAB in wine samples and enrichments thereof was compared. While the primer systems WBAC1/WBAC2GC and 341fGC/518r were not appropriate, the Lac1/Lac1o/Lac2GC primer set performed well. However, multiple bands complicated the evaluation. The rpoB1/rpoB1o/rpoB2GC set seemed to be promising for the detection of LAB in wine, although further improvements in terms of the detection limit need to be done. Due to the pronounced sensitivity and the sufficient discrimination of LAB at species level, the WLAB1/WLAB2GC primer system was found to be most suitable for studying the occurrence of LAB in wine.

Highlights ► Deoxynivalenol-3-glucoside (D3G) is hydrolyzed to deoxynivalenol during digestion. ► D3G is resistant to acids and enzymes expressed by humans. ► D3G is partly cleaved by cellulase and cellobiase. ► Several intestinal bacteria liberate deoxynivalenol from D3G. ► D3G is of toxicological relevance and should be monitored in food., Deoxynivalenol-3-β-d-glucoside (D3G), a plant phase II metabolite of the Fusarium mycotoxin deoxynivalenol (DON), occurs in naturally contaminated wheat, maize, oat, barley and products thereof. Although considered as a detoxification product in plants, the toxicity of this substance in mammals is currently unknown. A major concern is the possible hydrolysis of the D3G conjugate back to its toxic precursor mycotoxin DON during mammalian digestion. We used in vitro model systems to investigate the stability of D3G to acidic conditions, hydrolytic enzymes and intestinal bacteria, mimicking different stages of digestion. D3G was found resistant to 0.2 M hydrochloric acid for at least 24 h at 37 °C, suggesting that it will not be hydrolyzed in the stomach of mammals. While human cytosolic β-glucosidase also had no effect, fungal cellulase and cellobiase preparations could cleave a significant portion of D3G. Most importantly, several lactic acid bacteria such as Enterococcus durans, Enterococcus mundtii or Lactobacillus plantarum showed a high capability to hydrolyze D3G. Taken together these data indicate that D3G is of toxicological relevance and should be regarded as a masked mycotoxin.

Summary The effect of inulin and a multispecies probiotic formulation on performance and microbial parameters in a 28 days feeding trial with newly weaned piglets was assessed. Forty-eight piglets were allocated to a 2 × 2 factorial experiment involving two levels of inulin supplementation (0% or 0.4%) and two levels of probiotics (0 or 1 × 109 CFU/kg as fed, comprising enterococci, lactobacilli and bifidobacteria). In digesta samples obtained at slaughter (stomach, jejunum, ileum and colon), selected bacterial groups were enumerated and lactic acid, short chain fatty acids and ammonia concentrations analysed. The overall performance of piglets was unaffected by treatment. Inulin increased total aerobes in stomach and jejunum (p

SUMMARYThe aim of the current study was to compare three methods for determining the influence of different feeding strategies on the gut microbiota of piglets. Forty-eight weanling piglets were fed four different diets enriched with insoluble dietary fibre (wheat bran and pollen fromPinus massoniana). Starting from ileal and colonic samples, the total microbial DNA was isolated and bacterial parameters (lactobacilli, bifidobacteria,Bacteroides vulgatusand total bacterial counts) were quantified using real-time polymerase chain reaction (PCR). The results for lactobacilli, bifidobacteria and total bacterial counts were compared with those obtained by fluorescencein situhybridization (FISH) and cultivation method. No significant differences could be observed between dietary treatments with real-time PCR and FISH for all investigated parameters. Comparing the applied three methods no consistent results were achieved, whereas FISH usually showed lower values. It was shown that real-time PCR can be regarded as an alternative to conventional techniques and also as a complement to results obtained from conventional culture method.

The study aimed to investigate the effects of insoluble dietary fibre differing in lignin content on performance and parameters of gut microbiology in 48 weanling piglets (8.5 kg mean body weight) fed common diets ad libitum. Fibre sources tested were wheat bran (low lignin) and pollen from Chinese Masson pine (Pinus massoniana) as model of fibre rich in lignin, added to diets as follows: no addition (control), 3.0% wheat bran, 1.27% pine pollen and 2.55% pine pollen. In colonic chyme, bacterial colony counts remained unaffected by treatment, but ammonia contents were reduced by fibre additions (up to -38%). The effects on ammonia were best explained by added cellulose and lignin. Fibre additions reduced apparent (faecal) digestibility of dry matter (DM) and crude protein (CP) up to -3.5 and -4.3% units with cellulose and lignin being the major determinants for changes in CP digestibility.

The aim of the present study was to evaluate the influence of native, fermented and extruded wheat bran on the performance and intestinal morphology of piglets. Additionally, short-chain fatty acids (SCFA), biogenic amines, ammonia, lactic acid, pH as well as E. coli and lactic acid bacterial counts were analysed in digesta samples from three gut sections. Furthermore, the antioxidant potential in blood samples was evaluated based on the lipid radicals formed. For this purpose, 48 newly weaned piglets (28 d old) were allocated to one of the four different dietary treatment groups: no wheat bran (Control), native wheat bran, fermented wheat bran as well as extruded wheat bran. Wheat bran variants were included at 150 g/kg into the diets. All diets were mixed to reach the calculated isonitrogenic nutrient contents. Gut tissue and digesta samples were collected from the proximal jejunum, the terminal ileum and the colon ascendens, blood samples directly at slaughter. Although none of the dietary interventions had an impact on performance parameters, the amount of goblet cells in the ileum was increased upon feeding native and extruded wheat bran, compared to fermented bran (p

Strains of the genus Bifidobacterium are frequently used as probiotics, for which the absence of acquired antimicrobial resistance has become an important safety criterion. This clarifies the need for antibiotic susceptibility data for bifidobacteria. Based on a recently published standard for antimicrobial susceptibility testing of bifidobacteria with broth microdilution method, the range of susceptibility to selected antibiotics in 117 animal bifidobacterial strains was examined. Narrow unimodal MIC distributions either situated at the low-end (chloramphenicol, linezolid, and quinupristin/dalfopristin) or high-end (kanamycin, neomycin) concentration range could be detected. In contrast, the MIC distribution of trimethoprim was multimodal. Data derived from this study can be used as a basis for reviewing or verifying present microbiological breakpoints suggested by regulatory agencies to assess the safety of these micro-organisms intended for the use in probiotics.

Fourteen out of 17 laboratories completed an interlaboratory study comparing 2 pretreatment protocols of feed samples containing authorized probiotic bacilli spores. Both methods used tryptone soy agar for enumeration. Pretreatment A involved preparation of a suspension of the feed sample in 50% ethanol. For pretreatment B, the sample was suspended in peptone salt solution and heated at 80°C for 10 min. Each laboratory analyzed 12 samples (6 per pretreatment), which represented duplicates of a high (109 colony-forming units [CFU]/g) and low (105 CFU/g) level of bacilli spores or a blank that contained vegetative probiotic bacteria only. For pretreatment A, the re-peatability relative standard deviation (RSDr) was 2.9% for the low level and 2.5% for the high. The reproducibility relative standard deviation (RSDR) values were 7.8 and 5.9%, respectively. Pretreatment B revealed RSDr values of 1.1 and 1.0%, and RSDR values of 5.8 and 3.4%, respectively. The heat treatment (pretreatment B) of feed samples had better precision data, resulted in higher viable bacilli counts, and was more effective in deactivating vegetative background flora. It is therefore recommended for adoption for official control purposes and for CEN and ISO standards.