No description available.

This thesis investigates the factors which are suggested to affect perceptions of genetically modified (GM) foods. It first tests the extent to which the components of the Theory of Planned Behaviour and perceived 'outrage' are able to predict intentions towards buying GM foods using linear regression. It then focuses on how GM label design characteristics and linguistic variations influence perceptions of GM foods including measures of hazard perception and purchase intention using ANOVA repeated measures. Modelling is then used to identify whether label variations affect the components of the Theory of Planned Behaviour, namely attitudes, subjective norms and perceived behavioural control or whether their effect is by some other psychological process. As a result of the first six studies a model is proposed to explain the psychological process by which GM label variations affect behavioural intention for a specified product. The last two studies investigate the extent to which the previous findings generalise across products type using four different product types, two natural and two synthetic. The principle finding from this research is that some GM informational label design factors such as GM content, wording and use of the colour red have a strong stable effect across product type, whilst others such as label shape and font size are less consistent. The modelling suggests that GM label variations affect attitudes in particular, and to some extent subjective norms and perceived behavioural control which are then predictive of the behavioural intention. to buy GM foods. This thesis provides recommendations for those wishing to inform the public about the GM status of their product.

Heterocyclic amines (HCAs) are potential mutagenic and carcinogenic compounds present in almost every cooked meat dish. This PhD aims to develop methods to improve the assessment of dietary HCA intakes. A standardised method was developed for cooking steaks to different levels of doneness and TEP•UPLC•MS/MS was used to determine HCA content. Formation of HCAs in steaks increased with increasing doneness (p<O.OS), with considerable variation in HCA values both within a batch and between batches of the same doneness. The perception of done ness was evaluated by consumers using steaks and corresponding photographs. Results showed that photographs could be used equally as well as real steaks, and that the internal surface was superior to the external surface for r evaluating perception of doneness. Accurate dietary assessment of HCA intakes requires reliable food intake data, information on cooking method, and degree of doneness for r meats. To evaluate HCA intakes in human studies, a self-administered food frequency questionnaire (FFQ) designed specifically for HCA intakes was compared to a food diary (FO). The HCA intakes estimated by FFQ was significantly higher (p<O.OS) than the FO. However, using quintile analysis, both approaches ranked individuals similarly according to their HCA intakes in a similar way. The UK National Diet and Nutrition Survey (NDNS) database was used to estimate HCA intakes in the population. HCA intakes were Significantly higher (p<O.OS) in males than females, with a significant interaction (p<O.05) between gender and age. PCA analysis showed that zinc, iron, fat, saturated fat and sodium were associated with HCA intakes. Logistic regression analysis showed that being white and having a 8M I <25 or >30 were likely to be associated with the highest HCA intake quintile. This thesis showed the importance of; standardising cooking conditions, photographs (for doneness assessment) and a validated FFQ for estimating HCA intakes.

Cleaning of processing equipment in the food industry and of surfaces in catering and domestic environments is a key issue in prevention of accidental exposure of individuals with a food allergy to allergens. Ovomucoid was adsorbed onto different surfaces (stainless steel, formica and glass) in various amounts for different periods of time. Generally, when ovomucoid was in contact with any of the surfaces, more protein remained on the surface (as determined using the Bradford method) and more immunoreactivity remained (as determined by ELISA) when more protein was put on the surface or when it was left for a longer time. Ovomucoid adsorbed onto stainless steel and formica yielded higher protein remaining and immunoreactivity than was observed for the glass surface. Ovomucoid was heated in phosphate-buffered saline (pH 7.4) at different temperatures for 10 min, and heated in different aqueous solutions for various times, and also heated on different surfaces for various times. The results indicated that different antibody-based methods had different sensitivities in detecting the heated ovomucoid. When using one particular immunoassay, the immunoreactivity of ovomucoid increased rapidly after heating in water whereas immunoreactivity declined after heating in alkaline buffer (pH 10). Ovomucoid appeared more immunoreactive when dissolved in PBS (pH 7.4) and heated on a stainless steel surface. Isolated ovomucoid and ovomucoid within a model food mixture were adsorbed onto different surfaces until dry at ambient temperature before investigating removal of ovomucoid using different cleaning solutions. In general, NaOH and HCI solutions were more effective for removal of ovomucoid from surfaces even though some ovomucoid still remained on some surfaces. Isolated ovomucoid and ovomucoid present within a food mixture behaved differently as regards removal from different surfaces. To our knowledge, this is the first time that antibody-based methods have been applied for the detection of ovomucoid adsorbed onto different surfaces under various conditions. The results obtained suggest that food processors need to be aware of specific problems generated by particular food matrices and the type of surfaces and processes involved. False assurance will be given with the use of inappropriate, non-validated immunoassays such as those available commercially as 'Swab' tests. A greater understanding of antibody-protein interaction after processing of a protein is required.

This thesis is conducted in two parts. The first part investigates expert and lay representations of GM food risk using the Carnegie Mellon University approach (Granger Morgan at al, 2002) and social representations theory (Moscovici,1984). Elite interviews were followed by focus group discussions with lay people to explore how GM food risks are understood by both parties. Expert and lay perceptions differ on a wide range of issues. In contrast to experts, lay participants are particularly concerned with various non-scientific risk dimensions, such as trust and values. These moral and ethical concerns cannot be addressed through the provision of scientific information alone as the Carnegie Mellon University approach suggests. Social representations theory offers an alternative to this top-down approach by showing that, rather than erroneous knowledge, lay participants' non-scientific concerns express ways of understanding GM food. The second part of the thesis focuses on one particular non-scientific dimension of lay GM food representations, namely the concept 'messing with nature', and examines the social construction of nature and naturalness in relation to food. 188 respondents completed an internet-administered free associations task to establish in depth what lay people mean when they judge GM food to be 'unnatural'. The findings show that the concept of 'messing with nature ' can be firmly established as a major risk dimension in relation to GM food. Moreover, rather than being solely material, both food and nature have significant symbolic and affective dimensions. This indicates that GM food risks are social in part- they are representations that have socio-cultural and value dimensions and with all this they are disputed. In turn, this has a range of implications for risk communication.

Moving beyond democratically grounded models of participation, the thesis argues for participation to be organised around experiential expertise by speaking epistemically of levels of expertise held by experts whatever their social position and location. The thesis is then concerned with determining and defending the types of knowledge and experience pertinent to policy formation and decision-making held by scientific and citizen communities. The empirical work begins by showing that politically and legally, GM was only a technical issue, and so the space for alternative framings and citizen participation was formally limited. An exploration of alternative framings is given through Q methodology and analysing transcripts from public GM debates. Then, following a close analysis and comparison of the knowledges and rationalities used by debate participants, it is argued that the extended claim to public participation into the technical aspects of a policy or decision-making process must be limited to those with genuine technical expertise. However, the reverse is then argued for the political aspects of a decision; the empirical rationality utilised by technical experts, particularly from scientific communities, is inadequate to cope with the complex demands of technoscience in public policy and that, therefore, the presumed 'natural' relationship between 'experts' and policy must be reconfigured accordingly. A model is proposed that, for the practical purposes of getting business done, separates technical and politico-ethical capacities and decision-making procedures, and experts and citizens respectively.

No description available.

Small catering businesses represent the majority of the food industry and have an important role to play in the control of food borne disease. Since 1995 they have been required by law to operate risk-based food safety management in their businesses, based on the principles of Hazard Analysis Critical Control Point (HACCP). This was extended to a requirement for formal, documented HACCP-based systems in January 2006. HACCP is a theoretically effective risk management system, which takes a preventative, focused approach to managing food safety. However, it is a resource-heavy, time-consuming system, that is full of complex jargon and requires technical expertise to put into place. This poses a major problem for the majority of businesses in the industry, namely small catering operations with limited resources and technical expertise. This project utilised in-depth psychological research techniques through a 3- year iterative process of development, piloting, evaluation and review of a new risk-based approach to food safety management for the catering industry. In- depth narrative interviews and supporting documentary analysis were carried out with 22 catering businesses to identify the practical and psychological barriers involved in implementing food safety management systems in catering. The businesses were randomly selected from the North West of England and 100% of the original sample agreed to be interviewed when approached. A model of 21 barriers was identified from this work and was used to assist in the development of a new risk-based food safety management system. Six months following the implementation of the new system, the business managers still in post and available were re-interviewed and their documents were assessed. This enabled an in-depth analysis of any changes in their food safety knowledge, attitudes and behaviours as a result of using the system. Three years following the implementation of the new system, the managers still in post and available were interviewed and their documents were assessed a third time to assess longitudinal change. At both the six-month and three-year periods the system was shown to be highly successful in improving knowledge, attitudes and behaviour, and overcoming barriers to food safety management in the catering industry. The new system, named Safer Food Better Business, was officially adopted by the Food Standards Agency in 2005. It is now the recommended approach to food safety management for over 400,000 small catering businesses nationwide.

The aim of this thesis was to examine attitudes towards genetically modified (GM) food and how these translate into behaviour. Research conducted divided quite neatly into two distinct sections. The first section explored explicit attitudes and other socio-cognitive constructs relating to behaviour towards GM food within the framework of different theoretical models including, most notably, the theory of planned behaviour (Ajzen, 1991). The second section measured implicit attitudes held towards GM food and the malleability of these attitudes, using an array of different reaction time tasks, e. g. the implicit association task (Greenwald, McGhee and Schwartz, 1998). A final experiment then linked these two sections by examining both implicit and explicit attitudes alongside various measures of behaviour in order to examine the predictive validity of these attitude constructs and how these may vary depending on the situation. Results indicated that socio-cognitive concepts of subjective norms, perceived behavioural control (PBC), self-identity and emotional involvement were useful alongside the construct of explicit attitudes in predicting intentions and behaviour towards GM food. In addition, measures of implicit attitude were found to be useful predictors of behaviour towards GM food, over and above explicit attitudes. Interestingly, measurementso f implicit attitude were found to be positive when measured in a context free manner but were also found to be malleable and differed considerably depending on the situational context of measurement. Actual behaviour was measured in a variety of different ways and these converged in demonstrating that the majority of participants would try GM food. Overall, findings indicated that within Britain more people than previously thought are likely to try GM food if it becomes more widely available.

Les travaux présentés traitent des cinétiques de décrochement des biofilms bactériens formés au sein des équipements communément utilisé dans les agro-industries. Deux espèces bactériennes Pseudomonas et Bacillus ayant une forte capacité à former des biofilms dont la présence quasi permanente est reportés dans les industries alimentaires (viande, lait, légumes frais…) ont servi de modèles pertinent pour ces travaux. Par ailleurs Bacillus, bactéries potentiellement pathogènes capable de former des spores dont les capacités à adhérer et résister aux environnements chimiques et thermiques défavorables (détergents, traitement de pasteurisation, stérilisation) sont reconnues pour présenter un risque sanitaire majeur pour l’agro-industrie du fait de la contamination des produits alimentaires par l’outil de fabrication lui-même. Deux type d’études ont été effectués sur le nettoyage d’équipements utilisés en industrie agroalimentaire.Une première approche cinétique a été mise en œuvre pour étudier l’élimination de ces biofilms des surfaces au cours du nettoyage. Nous avons cherchés à identifier les rôles respectifs de l’action mécanique via la contrainte pariétale générée par l’écoulement ou chimique via différentes concentrations en NaOH puis la combinaison des deux actions chimiques et mécaniques. Un modèle biphasique a été proposé pour décrire ces cinétiques de nettoyage en pertinence avec deux phases très distinctes que nous interprétons comme l’élimination de deux fractions différentes du biofilm. Un détachement plus ou moins rapide (1 à 5 min) correspondrait à l’élimination de structure tridimensionnelles composées ou non d’exopolymères suivi par un détachement lent des cellules directement en contact avec les surfaces.Dans le cas des biofilms à Bacillus, il existe une fraction du biofilm composée par des spores pouvant représenter près de 90% du biofilm. Cette fraction particulière semble s’éliminer plus rapidement dans la première phase et pas du dans la seconde phase. Les données préliminaires sur biofilms mixtes montrent une résistance accrue de l’ensemble qui se traduit par une plus grande résistance de la partie de biofilm constituée par des cellules à Pseudomonas.La seconde thématique développée traite de la possible récontamination par les sopres de Bacillus décrochées lors du processus de nettoyage.La réadhésion des bactéries à pu être prouvée par le positionnement des tubes dans le circuit de nettoyage, ainsi que par l’utilisation d’un matériel complexe (vanne bidirectionnelle) communément utilisé dans les agro-industries. Ces travaux ont permis d’identifier les conditions présidant à cette récontamination. La conception hygiénique des outils de transformation prend tout son sens ici. / This work deals with removal kinetics of bacterial biofilms potentially formed in commonly used equipment in agro-industries. Two bacterial species Pseudomonas and Bacillus with a strong ability to form biofilms in which the almost permanent presence is reported in the food industry (meat, milk, vegetables…) were chosen as relevant models for the study. Moreover Bacillus, potentially pathogenic bacteria can form spores which are known to strongly adhere to solid surfaces and for their ability to withstand adverse environments as thermal and chemical detrimental conditions (detergents, pasteurization or sterilization temperatures). Bacillus species are known to pose a major health risk for agro-industry is contamination of food by the technical equipment itself.Two main areas were considered in the field of food processing equipment cleaning.At first a kinetic approach was implemented to study the removal of biofilms from surfaces during cleaning operations. Thus respective roles of the mechanical action (wall shear stress under turbulent flow regime), the chemical action (different NaOH concentrations) and the combination of both chemical and mechanical actions were studied. A biphasique model was proposed to describe cleaning kinetics according to the observation of two very different phases which we interpreted as the elimination of two different fractions of the biofilm. A more or less fast detachment in 1 to 5 min would correspond to the three-dimensional elimination of structure with more or less exopolymeric materials followed by a slow detachment of bacteria cells directly in contact with solid surfaces. In the case of Bacillus, can represent about 90% of the total biofilm. Spores removal appeared to be a two phases phenomenon as the whole biofilm. However, the removal was essentially observed during the short first phase of the kinetics. Preliminary data on mixed biofilms with both species Bacillus and Pseudomonas had shown an increase in their resistance to cleaning comparing to the corresponded monospecies biofilm counterpart. This is really significant for Pseudomonas. The second developed theme considered as a consequence of the above one deals with possible equipment re-contamination by Bacillus spores removed during cleaning operations. Post contamination of food processing equipment during cleaning was thus observed In pipes located at different places in the cleaning loop, as well as in more complex materials as a mixproof valve commonly encountered in Dairies. This work allowed us to identify all the conditions explaining such phenomenon. Equipment hygienic design issues appeared to be here.