1,721,055 research outputs found
Heat transfer model tool for the heat absorption capacity of superchilled fresh fishery products (HTM-SFFP Tool)
No full textIntroduction
This model was developed and applied by members of the EFSA Working Group on the transport/storage of fresh fishery products during the preparatory work on the BIOHAZ Scientific Opinion on the use of the so called 'superchilling' technique for the transport of fresh fishery products (EFSA-Q-2019-00437) (https://doi.org/10.2903/j.efsa.2021.6378).
A heat transfer modelling approach was used to identify under which initial configurations the fish temperature of superchilled fresh fishery products (SFFP), at any time during the storage/transport, is lower or equal to conventional fresh fishery products (CFPP), when exposed to the same conditions of on-land storage and/or transport. This approach is feasible when the boxes used to transport the fish (e.g. expanded polystyrene boxes) and the storage and transport conditions are the same for the two compared conditions (SFFP and CFFP).
The capacity of the CFFP and SFFP to maintain their temperature depends on their capacity to absorb heat, which is determined by their initial configurations. These are:
for CFFP: the initial fish and ice temperatures and the proportion of ice:fish in the box; and
for SFFP: the degree of superchilling, i.e. the ice fraction in the fish matrix, which depends on the fish temperature after superchilling and the initial freezing point of the fish.
The tool can be used as part of 'safety-by-design' approach of the food business operator to identify scenarios under which initial configurations the SFFP will be equivalent or have a higher capacity to absorb heat than CFFP.
The ratio (R) between the capacity to absorb heat between both systems can be determined as R=QS/QC. If R ≥ 1, then the SFFP temperatures are lower than those of CFFP. If R < 1, then the SFFP temperatures may be eventually higher than those of CFFP.
Description
A MS-Excel spreadsheet tool enables the setting of the degree of superchilling for SFFP that is considered able to maintain fish temperature below or equal to that a given configuration of CFFP regarding the initial fish temperature and the proportion of ice added per mass of fish (ice:fish) in the box (R ≥ 1, corresponding to QS ≥ QC). The tool facilitates identification of configurations under which the SFFP cannot be proved to be equivalent or better than CFFP (R < 1, corresponding to QS < QC).
The tool has the following options:
To derive if superchilling is able to maintain fish temperature below or equal to that of CFFP at any time of storage before all ice melts, based on
the target % of frozen free water in SFFP (option 1)
the initial superchilled fish temperature (option 2)
To derive the initial superchilled fish temperature and percentage of ice in superchilled fish needed to equal the absorbing heat capacity of CFFP before all ice melts (option 3)
To derive the proportion of ice in CFFP to equal the absorbing heat capacity of SFFP before all ice melts, based on
the target % of frozen free water in SFFP (option 4)
the initial superchilled fish temperature (option 5)
In each option there is the possibility to estimate the initial freezing point of fish and free water of fish from the proximate composition; more in particular, from the fish composition regarding the content of water, protein ash and other than ash, water, proteins or fat (such as carbohydrates).
The reliability of the outcome provided by the tool depends on the accuracy of the input data introduced by the user.
More details about the methodology can be found in section 2.1.1. and results of modelling can be found in section 3.1.1 of the opinion. The uncertainties related to the outcome of the heat transfer model are described in section 3.1.4 of the opinion.EU; XLSX; [email protected]
Horizontale besmetting van eieren met Salmonella: mechanismen en beheersing
No full textSalmonella enterica serovar Enteritidis (S. Enteritidis) was the main cause of reported human salmonellosis cases in 2009 in the EU. Raw eggs and egg products are pinpointed as the leading sources of human S. Enteritidis. In Belgium, a decrease in the reported human S. Enteritidis cases can be observed since 2004, partly due to the vaccination of laying hens. This transfers the attention from vertical to horizontal contamination of table eggs. Moreover, the Council Directive 1999/74/EC will abolish conventional cages by 2012. Keeping hens on the floor or outside was hypothesized to increase the risk of contamination of eggs, although recent studies showed that this is unlikely to occur. Nonetheless, eggs still can get contaminated by S. Enteritidis. Thus, it is of interest to investigate the role of egg components in contributing to variation in the eggs antimicrobial defence and to study egg treatments to reduce the potential risk of bacterial egg contamination. Chapter 1 gives a general introduction to the topics discussed or studied in the following chapters of which the objectives are presented in chapter 2. The vitelline membrane is the barrier to prevent bacterial penetration into the nutrient-rich yolk contents. In chapter 3, the correlation between the occurrence of S. Enteritidis penetration through the vitelline membrane and the characteristics of the latter is investigated. The study, based on the results of successive eggs, showed that the vitelline membrane strength and the vitelline membrane proteins with molecular weights within the range of 21.5 and 31 kDa influenced the occurrence of Salmonella penetration through the vitelline membrane. Chapter 4 evaluates the importance of the integrity of the eggshell as the first barrier in horizontal contamination by Salmonella during or after oviposition. The role of the cuticle and microcracks in trans-shell penetration by S. Enteritidis is determined. In this study, it was found that microcracks most probably do not present a major risk for horizontal contamination. Yet, this risk can be enhanced by the origin of the eggs. The importance of the cuticle in protecting the egg contents against S. Enteritidis penetration was confirmed by comparing eggs with a good cuticle coverage to eggs with the cuticle removed. Lowering the shell contamination will lead to a reduction in horizontal contamination. The advantage of egg washing in lowering the shell contamination has already been proven in other studies. However, the effect of egg washing on the cuticle of eggs is an interesting issue as damage to the cuticle would be disadvantuous as shown in chapter 4. In chapter 5, the effect of a commercial Swedish egg washing procedure on the cuticle quality was studied. Based on the determination of the cuticle coverage and an ultrastructural assessment of the cuticle quality, no evidence was found that the commercial washing procedure used in the study changed the cuticle quality of the eggs tested. A new potential treatment for lowering the risk of contamination of the egg contents is coating of eggs with chitosan, as the latter is an antimicrobial polysaccharide. In chapter 6, a chitosan type with a molecular weight of 310-375 kDa and a degree of deacetylation of 75% was selected out of eight types tested. This selection was based on their antimicrobial activity against S. Enteritidis using the developed contact plate method. However, when applied as an eggshell coating, its effectivity in reducing Salmonella shell contamination could not be proven. On the other hand, a decrease in the occurrence of trans-shell penetration was found when a 2% chitosan coating solution was used. Several studies showed the advantageous effect of a chitosan eggshell coating on the conservation of the internal quality. In chapter 7, this effect was determined using the chitosan with a molecular weight of 310-375 kDa and a degree of deacetylation of 75% (chapter 6) and based on multiple, also less frequent, quality parameters, viz. air chamber height, albumen pH, Haugh unit, vitelline membrane strength, percentage weight loss, yolk colour, and yolk index. When the eggs were coated with a 1% or 2% chitosan solution, its effectiveness in conserving the internal egg quality was confirmed. Based on the albumen pH, eggs coated with a 1% or 2% chitosan solution preserve egg quality four weeks longer than uncoated eggs.status: Publishe
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
No full text“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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