Hespellia stercorisuis gen. nov., sp nov and Hespellia porcina sp nov., isolated from swine manure storage pits

Four Gram-positive-staining, strictly anaerobic, non-spore-forming, rod-shaped organisms were isolated from a pig manure storage pit. Comparative 16S rRNA gene sequence analysis revealed that the isolates belonged to two related but distinct groups. Sequence analysis showed that the two groups of isolates were highly related to each other (approx. 97% 16S rRNA gene sequence similarity), forming a distinct cluster within the Clostridium coccoides suprageneric rDNA grouping. Biochemical and physiological studies confirmed the division of the isolates into two related, albeit distinct, groups. Based on both phenotypic and phylogenetic evidence, it is proposed that the unidentified rod-shaped isolates from pig manure should be classified in a novel genus, Hespellia gen. nov., as Hespellia stercorisuis sp. nov. and Hespellia porcina sp. nov. The type species of the novel genus is H. stercorisuis (type strain, PC18(T) = NRRL B-23456(T) = CCUG 46279(T) = ATCC BAA-677(T)) and the type strain of H. porcina is PC80(T) (= NRRL B-23458(T) = ATCC BAA-674(T)).

Bacteroides coprosuis sp nov., isolated from swine-manure storage pits

Two Gram-negative, anaerobic, non-spore-forming, rod-shaped organisms were isolated from a swine-manure storage pit. Based on morphological and biochemical criteria, the strains were tentatively identified as belonging to the genus Bacteroides but they did not appear to correspond to any recognized species of the genus. Comparative 16S rRNA gene sequencing studies showed that the strains were related closely to each other and confirmed their placement in the genus Bacteroides, but sequence divergence values of > 10% from reference Bacteroides species demonstrated that the organisms from manure represent a novel species. Based on biochemical criteria and molecular genetic evidence, it is proposed that the unknown isolates from manure be assigned to a novel species of the genus Bacteroides, as Bacteroides coprosuis sp. nov. The type strain is PC139(T) (=CCUG 50528(T)=NRRL B-41113(T)).

Velocity profiles and frictional pressure drop for shear thinning materials in lid-driven cavities with fully developed axial flow

A finite element numerical study has been carried out on the isothermal flow of power law fluids in lid-driven cavities with axial throughflow. The effects of the tangential flow Reynolds number (Re-U), axial flow Reynolds number (Re-W), cavity aspect ratio and shear thinning property of the fluids on tangential and axial velocity distributions and the frictional pressure drop are studied. Where comparison is possible, very good agreement is found between current numerical results and published asymptotic and numerical results. For shear thinning materials in long thin cavities in the tangential flow dominated flow regime, the numerical results show that the frictional pressure drop lies between two extreme conditions, namely the results for duct flow and analytical results from lubrication theory. For shear thinning materials in a lid-driven cavity, the interaction between the tangential flow and axial flow is very complex because the flow is dependent on the flow Reynolds numbers and the ratio of the average axial velocity and the lid velocity. For both Newtonian and shear thinning fluids, the axial velocity peak is shifted and the frictional pressure drop is increased with increasing tangential flow Reynolds number. The results are highly relevant to industrial devices such as screw extruders and scraped surface heat exchangers. (c) 2006 Elsevier Ltd. All rights reserved.

Effect of storage temperature and media composition on the survivability of Bifidobacterium breve NCIMB 702257 in a malt hydrolisate

The aim of this study was to evaluate the survivability of Bifidobacterium breve NCIMB 702257 in a three malt-based media supplemented with cysteine and yeast extract, and to determine the protective effect of these growth factors. A number of parameterised mathematical models were used to predict of kinetics of viability and total acidity during storage at different temperatures. Results demonstrated a good fit to the experimental mathematical model. The Arrhenius equations showed only reasonable fits and the polynomial plots contained a large area without data between 4 and 25 degrees C. In addition, it was shown that cysteine promotes growth and acid production by bifidobacteria, but does not extend survivability. On the other hand, increasing the yeast extract content of the fermentation media enhances the survivability of B. breve. To our knowledge, this is the first study to address the modelling of the survivability of probiotic bacteria in a cereal based fermentation media at different temperatures, introducing a more quantitative approach to the study of the shelf-life of a probiotic product. (C) 2009 Elsevier B.V. All rights reserved.

Viability of Salmonella enterica subsp. enterica during the preparation and cold storage of Egyptian soft cheeses and ice-cream

Changes occurring in the viability of Salmonella enterica subsp. enterica during the preparation and cold storage of Domiati cheese, Kariesh cheese and ice-cream were examined. A significant decrease in numbers was observed after whey drainage during the manufacture of Domiati cheese, but Salmonella remained viable for 13 weeks in cheeses prepared from milks with between 60 and 100 g/L NaCl; the viability declined in Domiati cheese made from highly salted milk during the later stages of storage. The method of coagulation used in the preparation of Kariesh cheese affected the survival time of the pathogen, and it varied from 2 to 3 weeks in cheeses made with a slow-acid coagulation method to 4-5 weeks for an acid-rennet coagulation method. This difference was attributed to the higher salt-in-moisture levels and lower pH values of Kariesh cheese prepared by the slow-acid coagulation method. A slight decrease in the numbers of Salmonella resulted from ageing ice-cream mix for 24 h at 0degreesC, but a greater reduction was evident after one day of frozen storage at -20degreesC. The pathogen survived further frozen storage for four months without any substantial change in numbers.

Vacuum-induced bubble formation in liquid-tempered chocolate

Bubble inclusion is one of the fastest growing operations practiced in the food industry. A variety of aerated foods is currently available in supermarkets, and newer products are emerging all the time. This paper aims to combine knowledge on chocolate aeration with studies performed on bubble formation and dispersion characteristics. More specifically, we have investigated bubble formation induced by applying vacuum. Experimental methods to determine gas hold-up (volume fraction of air), bubble section distributions along specific planes, and chocolate rheological properties are presented. This study concludes that decreasing pressures elevate gas hold-up values due to an increase in the number of bubble nuclei being formed and release of a greater volume of dissolved gases. Furthermore, bubbles are observed to be larger at lower pressures for a set amount of gas because the internal pressure needs to be in equilibrium with the surrounding pressures. Temperature-induced changes to the properties of the chocolate have less of an effect on bubble formation. On the other hand, when different fats and emulsifiers are added to a standard chocolate recipe, milk fat was found to increase, significantly, the gas hold-up values and the mean bubble-section diameters. It is hypothesized that this behavior is related to the way milk fats, which contain different fatty acids to cocoa butter, crystallize and influence the setting properties of the final product. It is highlighted that apparent viscosity values at low shear rate, as well as setting behavior, play an important role in terms of bubble formation and entrainment.

Influence of some processing and storage conditions on the mechanical properties of oat flakes

Flake breakage and texture are important quality, criteria in oat flakes. These properties are determined by the mechanical properties of the flakes, which may be influenced by process variables such as kilning and flake thickness. A pin deformation method was used to measure the rupture force of individual oat flakes at different water activities. The monolayer value of ground oat flakes ranged from 5.83 to 684 g/100 g dry matter Thick flakes were strongest, requiring 3.4 N to rupture the flake compared to 2.2 N for the thin flakes. Water softened the flakes, causing a decrease in rupture force from 3.6 N to 2.4 N as water activity; increased from 0.115 to 0.848. Kilning had a significant effect on flake thickness but not on the mechanical properties. This study suggests that oat flakes should be stored at water activity 0.4 or less as there is a sharp loss of flake strength above this point.

An insight into the mechanism of protein separation by colloidal gas aphrons (CGA) generated from ionic surfactants

Colloidal gas aphrons (CGA), which are surfactant stabilised microbubbles, have been previously applied for the recovery of proteins from model mixtures and a few studies have demonstrated the potential of these dispersions for the selective recovery of proteins from complex mixtures. However there is a lack of understanding of the mechanism of separation and forces governing the selectivity of the separation. In this paper a mechanistic study is carried out to determine the main factors and forces influencing the selectivity of separation of whey proteins with CGA generated from ionic surfactants. Two different separation strategies were followed: (i) separation of lactoferrin and lactoperoxidase by anionic CGA generated from a solution of sodium bis-(2-ethyl hexyl) sulfosuccinate (AOT); (ii) separation of beta-lactoglobulin by cationic CGA generated from a solution of cetyltrimethylammonium bromide (CTAB). Separation results indicate that electrostatic interactions are the main forces determining the selectivity however these could not completely explain the selectivities obtained following both strategies. Protein-surfactant interactions were studied by measuring the zeta potential changes on individual proteins upon addition of surfactant and at varying pH. Interestingly strongest electrostatic interactions were measured at those pH and surfactant to protein mass ratios which were optimum for protein separation. Effect of surfactant on protein conformation was determined by measuring the change in fluorescence intensity upon addition of surfactant at varying pH. Differences in the fluorescence patterns were detected among proteins which were correlated to differences in their conformational features which could in turn explain their different separation behaviour. The effect of conformation on selectivity was further proven by experiments in which conformational changes were induced by pre-treatment of whey (heating) and by storage at 4 degrees C. Overall it can be concluded that separation of proteins by ionic CGA is driven mainly by electrostatic interactions however conformational features will finally determine the selectivity of the separation with competitive adsorption having also an effect. (c) 2006 Elsevier B.V. All rights reserved.

Atopostipes suicloacale gen. nov., sp. nov., isolated from an underground swine manure storage pit

Phenotypic and molecular genetic studies were performed on an unknown facultative anaerobic, catalase-negative, non-spore-forming, rod-shaped bacterium isolated from a pig manure storage pit. The unknown bacterium was nutritionally fastidious with growth enhanced by the addition of rumen fluid and was phenotypically initially identified as an Eubacterium species. Comparative 16S rRNA gene sequencing studies, however, revealed that the unknown bacterium was phylogenetically distant from Eubacterium limosum (the type species of the genus Eubacterium) and related organisms. Phylogenetically, the unknown species displayed a close association with an uncultured organism from human subgingival plaque and formed an unknown sub-line within a cluster of organisms which includes Alloioccoccus otitis, Alkalibacterium olivoapovliticus, Allofustis seminis, Dolosigranulum pigrum, and related organisms, within the low mol% G + C Gram-positive bacteria. Sequence divergence values of > 8% with all known taxonomically recognised taxa, however, clearly indicates the novel bacterium represents a hitherto unknown genus. Based on both phenotypic and phylogenetic considerations, it is proposed that the unknown bacterium from pig manure be classified in a new genus and species, as Atopostipes suicloacale gen. nov., sp. nov. The type strain of Atopostipes suicloacale is PPC79(T) = NRRL 23919(T) = DSM 15692(T). Crown Copyright (C) 2004 Published by Elsevier Ltd. All rights reserved.

The effects of low-temperature potato storage and washing and soaking pre-treatments on the acrylamide content of French fries

BACKGROUND: Since the discovery in 2002 of acrylamide in a wide range of foods, there has been much work done to explore mechanisms of formation and to reduce acrylamide in commercial products. This study aimed to investigate simple measures which could be used to reduce acrylamide formation in home-cooked French fries, using potatoes from three cultivars stored under controlled conditions and sampled at three time points. RESULTS: The reducing sugar content for all three cultivars increased during storage, which led to increased acrylamide levels in the French fries. Washing and soaking (30 min or 2 h) raw French fries before cooking led to reductions in acrylamide of up to 23, 38 and 48% respectively. Pre-treated fries were lighter in colour after cooking than the corresponding controls. CONCLUSION: Pre-treatments such as soaking or washing raw French fries in water reduce acrylamide and colour formation in the final product when cooking is stopped at a texture-determined endpoint. (c) 2008 Society of Chemical Industry.

A little learning is a dangerous thing: an experimental demonstration of ignorance-driven inference

Studies of ignorance-driven decision making have been employed to analyse when ignorance should prove advantageous on theoretical grounds or else they have been employed to examine whether human behaviour is consistent with an ignorance-driven inference strategy (e. g., the recognition heuristic). In the current study we examine whether-under conditions where such inferences might be expected-the advantages that theoretical analyses predict are evident in human performance data. A single experiment shows that, when asked to make relative wealth judgements, participants reliably use recognition as a basis for their judgements. Their wealth judgements under these conditions are reliably more accurate when some of the target names are unknown than when participants recognize all of the names (a "less-is-more effect"). These results are consistent across a number of variations: the number of options given to participants and the nature of the wealth judgement. A basic model of recognition-based inference predicts these effects.

Semantic-driven context-aware visual information indexing and retrieval: applied in the film post-production domain

A large volume of visual content is inaccessible until effective and efficient indexing and retrieval of such data is achieved. In this paper, we introduce the DREAM system, which is a knowledge-assisted semantic-driven context-aware visual information retrieval system applied in the film post production domain. We mainly focus on the automatic labelling and topic map related aspects of the framework. The use of the context- related collateral knowledge, represented by a novel probabilistic based visual keyword co-occurrence matrix, had been proven effective via the experiments conducted during system evaluation. The automatically generated semantic labels were fed into the Topic Map Engine which can automatically construct ontological networks using Topic Maps technology, which dramatically enhances the indexing and retrieval performance of the system towards an even higher semantic level.