Fresh produce has been implicated in several foodborne outbreaks. A primary site of microbial contamination for produce occurs on the surface during production and handling. An approach to reduce contamination is to sample the surface of produce. This study used different detergent agents at 22&#176;C and 40&#176;C to determine their efficacy for recovery of pathogenic bacteria, from surfaces of several produce types and examined survival of organisms in detergents over time. Strawberries, tomatoes and green leaf lettuce were dip inoculated in a 6-6.5 LOG CFU/ml cocktail of nalidixic acid resistant organisms. After drying, produce were rinsed with either 0.1 % sodium lauryl sulfate (SLS), 0.1% Tween 80, or water at different temperatures. Rinse solutions were plated onto Tryptic Soy agar supplemented with 50-ppm nalidixic acid (TSAN). About 4 LOG CFU/ml of Salmonella, and 3-LOG CFU/ml Shigella were recovered, with slightly lower recovery from tomatoes. Inoculated strawberries rinsed with SLS, displayed minimal recovery at ~1.5-LOG CFU/ml at 22&#176;C, and <1-LOG CFU/ml at 40&#176;C. When whole strawberries treated with SLS were analyzed, few Salmonella were recovered. Lack of recovery of Salmonella rinsed with SLS, suggests SLS may be inactivating Salmonella, especially at elevated temperatures. Detergent solutions were inoculated with 3-LOG CFU/ml cocktail and incubated for up to 32 hours at 22&#176;C, and 40&#176;C. Aliquots were plated onto TSAN at varying times. All solutions at 40&#176;C allowed Shigella to grow. SLS gave initial drops in Salmonella populations followed by slight recovery. SLS may cause an initial injury of Salmonella. While organisms were able to survive in detergents, the application of detergents to produce was no more effective in recovery of organisms from produce than water. / Master of Science

Thesis (MSc)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: The consumption of fresh produce has increased over the past few decades, but it has also resulted in an increase in foodborne outbreaks. Once fresh produce gets contaminated, microbes can survive or even multiply on the produce. There is, however, very little information available on what impact environmental conditions will have on the survival and growth of potential pathogens. Thus the purpose of the first phase of the study was to determine the impact of different environmental factors: carbon levels; temperature; incubation time; and initial microbial load on the growth of E.coli and other "indigenous" microbes present in the Plankenburg river water. Water from the Plankenburg River was incubated at 10° to 35°C and the E.coli and aerobic (ACC) loads determined at 0, 6, 12 and 24 h. The impact of different COD:N:P ratios on growth were also evaluated by altering the water values. It was found that in non-sterile river water the E.coli levels increased with increase in incubation temperature. Minimal growth took place between 10° and 20°C and the largest growth increases at 35°C. The data showed that E.coli dieoff was rapid when the nutrient levels were low. It was concluded that the carbon (COD) level is a major growth limiting factor in river water. The impact of adjusted carbon levels on the growth of E.coli present was then evaluated. The E.coli was found to die-off faster at the higher temperatures when the carbon levels were low (COD = <10 mg.L-1), possibly due to nutrient limitations. At higher carbon levels (COD = >100 mg.L-1), the growth profiles of E.coli showed major growth increases with no die-off during the 24 h period, probably because of the availability of sufficient nutrient levels. Even though standard methods can be used to identify if irrigation water is faecally contaminated it is important to confirm that organisms on fresh produce are from the faecally polluted irrigation water. The purpose of the second study was to determine the effect of daily irrigation on carry-over, the effect of “once-off” irrigation on the survival of E.coli on the produce, identifying types of E.coli in the irrigation water and those on irrigated fresh produce, and then linking the E.coli types. In the first trial, green beans planted in a tunnel and irrigated on a daily basis (14 days) with Plankenburg water and a “pure wild-type” E.coli at a concentration of 106 cfu.mL-1 were evaluated. The results showed that E.coli is carried over from irrigation water to the irrigated green beans, especially when the E.coli levels in the river water were high. After the enumeration steps, colonies from both the irrigation water and from the irrigated beans were selected (67 isolates from the green beans and 72 from the irrigation water). Unique phenotypic (API) profiles were generated for each isolate. The first indication of linking was confirmed based on the degree of phenotypic similarity using numerical clustering systems. The results showed that these isolates were related and originated from the same pollution source. The use of PCR further confirmed (uidA positive) that all the phenotypically identified strains were E.coli. With multiplex PCR, further linking confirmation was shown when strains tested positive for the mdh gene. The presence of EPEC strains in the irrigation water was also revealed. Thirteen E.coli isolates, which showed positive carry-over links between the irrigation water and the green beans, were further analysed using triplex PCR. However, no direct phylogenetic link to the three main phenotypic E.coli clusters was found. However the triplex PCR could be of value in identifying the source of faecal pollution. For further linking confirmation, DNA sequencing was done on selected phenotypically clustered strains. The oriC-locus sequencing was unsuccessful in distinguishing between the different E.coli strains while the dnaJ sequences showed clear differences and similarities between E.coli strains and some E.cloacae and K.pneumoniae strains respectively from the river water and from the beans. The probability of faecal coliforms being carried-over from irrigation water to fresh produce was shown. This showed the importance of a "multi-method" approach to confirm carryover. / AFRIKAANSE OPSOMMING: Tydens die afgelope paar dekades het die verbruik van vars groente en vrugte vermeerder, maar dit het ook gepaard gegaan met ‘n toename in voedselverwante uitbrekings. Indien vars groente of vrugte gekontamineer word, kan die mikrobes daarop oorleef en ook vermeerder. Daar is min informasie beskikbaar oor die impak van omgewingskondisies op die oorlewing en groei van potensiële patogene. Dus was die doel van die eerste fase van die studie om die impak van verskillende omgewingsfaktore te bepaal: koolstofvlakke; temperatuur; inkubasietyd; en aanvanklike mikrobiese lading op die groei van E.coli en ander “inheemse” mikrobes wat teenwoordig is in die Plankenburg Rivier water. Water van die Plankenburg Rivier was geïnkubeer by 10° tot 35°C en die E.coli en aërobe kolonie tellings (AKT) was bepaal by 0, 6, 12 en 24 h. Die impak van verskeie CSB:S:F verhoudings op groei, was ook geëvalueer deur die waarders van die rivierwater te verander. Dit was gevind dat in die nie-steriele rivierwater, die E.coli vlakke vermeerder het soos die inkubasie temperatuur vermeerder het. Minimale groei het plaasgevind by 10° en 20°C en die meeste groei by 35°C. Die data het gewys dat die E.coli vinnig afgesterwe het as die nutriënt vlakke laag was. Die gevolgtrekking was dat die koolstofvlakke (CSB) die hoof faktor is wat die groei beperk in rivierwater. Die impak van die aangepasde koolstofvlakke op die groei van E.coli teenwoordig was ook geevalueer. Daar was gevind dat die E.coli vinniger afsterf by die hoër temperature as die koolstofvlakke laag is (CSB = <10 mg.L-1), omdat die nutriente moontlik beperk is. Tydens die hoë koolstofvlakke (CSB = >100 mg.L-1), het die E.coli groeiprofiele baie groei getoon met geen afsterwe tydens die 24 h periode nie, omrede dat daar moontlik genoeg nutriente beskikbaar was. Al kan standaard metodes gebruik word om fekale kontaminasie in besproeiingswater te identifiseer, is dit belangrik om te kan bevestig of die organismes op vars groente of vrugte van fekale gekontamineerde besproeiingswater is. Die doel van die tweede fase van die studie was om die effek van daaglikse besproeiing op oordrag te bepaal, effek van eenkeer se besproeiing op die oorleweing van E.coli op groenboontjies, identifisering van E.coli tipes in die besproeiingswater en op die groenboontjies, asook die koppeling van E.coli tipes. In die eerste proef was groenboontjies geplant in ‘n tonnel en daagliks besproei (14 dae) met Plankenburg water en ‘n “suiwer wilde-tipe” E.coli met ‘n konsentrasie van 106 cfu.mL-1. Die resultate het getoon dat E.coli oorgedra was van die besproeiingswater na die besproeide groenboontjies, veral toe die E.coli vlakke in die rivierwater hoog was. Na al die isoleringsstappe, is kolonies van die besproeiingswater en van die besproeide groenboontjies geselekteer (67 isolate van die groenboontjies en 72 van die besproeiingswater). Unieke fenotipiese (API) profiele was gegenereer vir elke isolaat. Die eerste indikasie van koppeling was bewys deur die graad van soortgelyke fenotipiese profiele deur numeriese groepering. Die resultate het gewys die isolate was verwant en oorspronklik van dieselfde bron van kontaminasie. Die gebruik van PKR het verder bewys (uidA positief) dat al die fenotipiese geidentifiseerde isolate E.coli was. Verdere koppeling was geidentifiseer met die multiplex PKR deurdat die isolate positief getoets het vir die mdh geen. Die teenwoordigheid van die EPEC isolate in die besproeiingswater was ook gevind. Dertien E.coli isolate, wat positiewe oordrag verbinding getoon het tussen die besproeiingswater en die groenboontjies, was verder geanaliseer deur triplex PKR. Geen direkte fenotipiese verbinding met die drie hoof fenotipiese E.coli groepe was egter gevind nie. Die triplex PKR kan wel van waarde wees om die bron van die fekale besoedeling te identifiseer. Vir verdere koppeling bevestiging, was DNA volgorde gedoen op isolate van geselekteerde fenotipiese groepe. Die oriC-locus volgorde was onsuksesvol om te onderskei tussen die verskillende E.coli tipes, terwyl die dnaJ volgordes duidelike verskille en ooreenstemmings getoon het tussen die E.coli asook party E.cloacae en K.pneumoniae tipes, onderskeidelik van die rivierwater en boontjies. Die waarskynlikheid van oordrag van fekale kolvorme vanaf besproeiingswater na vars goedere was getoon. Dit wys die belangrikheid van ‘n “multi-metode” benadering om oordrag te bewys.

Submitted by (edna.saturno@ufrpe.br) on 2016-06-10T11:12:31Z No. of bitstreams: 1 Vanessa Priscila Mamed Ali.pdf: 3876677 bytes, checksum: 624534c0b7f0189367b6335d2ec4229a (MD5) / Made available in DSpace on 2016-06-10T11:12:31Z (GMT). No. of bitstreams: 1 Vanessa Priscila Mamed Ali.pdf: 3876677 bytes, checksum: 624534c0b7f0189367b6335d2ec4229a (MD5) Previous issue date: 2013-06-10 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The objective of this research was to identify the statuos of the organization and hygiene problems found in the free markets of Afogados, Casa Amarela, Cordeiro e São José, in the city of Recife-PE. The methodologies adopted which supported this research were: questionnaires for consumers and merchants, in the field research, interviews with managers of trade bodies and government agencies, research bibliographic and photographic record. Such research has identified organizational problems regarding standardization of stalls / booths, difficult access and flow, human organ neglect sanitary supervision both in the handling of products, as environmental hygiene. They also identified the non periodicity of garbage collection causing bad smell due to perishable food. It was also observed that the fairs do not meet the requirements established by Csurb, and that most researched fairs are in a state of complete abandon. The results are presented through tables, graphs and pictures, which show the need for a revision to the rules of organization of fairs and training courses to promote the vendors regarding food handling, maintain by the government to collect garbage and inspection of fairs. / O objetivo desta pesquisa foi identificar aspectos organizacionais e de qualidade dos processos de comercialização de produtos hortifrutícolas bem como analisar algumas características dos atores da demanda e da oferta nas principais feiras livres associadas aos mercados públicos do Recife. As metodologias adotadas que subsidiaram esta pesquisa foram: aplicação de questionários para consumidores e feirantes, em pesquisa de campo, entrevista com orgãos gestores das feiras e orgãos públicos, pesquisa bibliografica envolvendo a revisão de dissertações, jornais, revistas, artigos e registro fotográfico. A referida pesquisa identificou problemas de organização em relação a padronização das bancas/barracas, dificuldade de acesso e de fluxo humano, o descaso de orgãos sanitários na fiscalização tanto da manipulação dos produtos, quanto da higienização do ambiente. Também foi identificada a não periodicidade da coleta de lixo causando mau cheiro devido a pericividade dos alimentos. Observou-se ainda, que as feiras não cumprem as exigências estabelecidas pela Csurb, e que a maior parte das feiras pesquisadas estão em estado de completo abandono. Os resultados são apresentados por meio de tabelas, gráficos e imagens, que apontam a necessidade de uma revisão para as regras de organização das feiras livres bem como promover cursos de capacitação para os feirantes referente a manipulação de alimentos, manter por parte do governo a coleta de lixo e a fiscalização das feiras livres.

A few vertically integrated retail chains increasingly dominate South Africa’s agro-food supply chain. M+M Planet Retail (2004) placed the market concentration among retailers to be as high as 96% for the top four chains leaving only 4% to the small competitors. The onset of this trend has led to the demise of a large number of “mom and pop” general dealers in favour of the sleek new stores as they were either priced or bought out of business. Players in the fresh produce market have proved to be resilient to this onslaught. The green grocers and hawkers have survived the “category killers” and appear to be able to face this competition head on. It is this resilience that is of interest to this study. The review of literature revealed a dearth of studies and hence methodology into the nature of the interaction between the three forms of retail. A preliminary survey also revealed the lack of coherent and detailed information, particularly among the greengrocers and hawkers. Thus the established methods of modelling competition analysis, namely the Structure Conduct Performance and the New Empirical Industrial Organisation frameworks, were deemed inappropriate. The study therefore took an exploratory form that relied on measures of central tendency and the perceptions of leading industry practitioners to reveal the nature and magnitude of competition between supermarkets, green grocers and hawkers. The study primarily drew on ‘Porter’s forces’ competition model to structure the investigation. It also employed a chain analysis approach including supply and value chain analysis (VCA) tools to analyse this competition. The study therefore sought to unpack the retail sections of the three chains in terms of identifying role-players; their relationships and interaction; as well as to account for the relative values that different types of fresh produce retailers generated for the final consumer. Besides the contribution to the general body of knowledge about the nature of the system that feeds us, this study provides means for the competing channels to upgrade and improve efficiency. A developmental and empowerment point of view was emphasised in the research, as such, identifying possible measures to upgrade and improve the informal sector was given precedence. The objective was to describe and analyse the competitive environment in which FFV was retailed in the Tshwane through a determination of the competitive and strategic behaviour of retailers and a mapping the flow of value. It was hypothesised that fresh produce retailers competed by varying elements of their marketing mix to suit their niche markets. The investigation was conducted in two phases; a pilot study followed by a survey involving a six-step sampling frame targeting a total of 120 respondents including 15 supermarkets, 30 greengrocers and 75 hawkers. This analysis was limited to the bounds of the Tshwane metropolitan area, South Africa, and focused on six fresh fruits and vegetable lines concurrently traded by supermarkets, greengrocers and hawkers. The main findings of the investigation include that tri-dimensional FFV retail competition was most intense in the middle-income areas of the city. The low income areas were dominated by informal traders while the large supermarkets chains and the large format greengrocers dominated the high income areas. The non-syndicated greengrocers were confined to the middle-income areas where competition was most intense. When the marketing strategies and chain maps were compared it was concluded that the tridimensional competitive environment was facilitated by the existence of multiple niches; the equalising effect of produce market based pricing; the general upgrade in product quality offered by all retailers; characteristics of fresh produce itself as compared to other foodstuffs and the existence of multiple market niches in the sector. Concluding the study were recommendations to improve (upgrade) the marketing performance of each of the three channels. / Dissertation (MSc(Agric) (Agricultural Economics))--University of Pretoria, 2007. / Agricultural Economics, Extension and Rural Development / MSc(Agric) / unrestricted

This dissertation analyzed consumer primary motivations for attending farmers' markets, preferences for product features, and differentiated produce. We used consumer survey data collected at farmers' markets in Nevada and Utah during summers of 2008 and 2011, respectively. This dissertation consists of three essays. The first essay employed binary and multinomial logistic models to assess primary consumer motivations for attending farmers' markets. Results indicate that many consumers attend farmers' markets primarily to purchase fresh produce. Other motives such as social interaction, purchasing ready-to-eat food, and buying packaged foods, arts, and crafts were also analyzed. In this first essay, consumers who attended farmers' markets were clustered into three groups based on their similar characteristics. Results from this essay are useful to vendors at farmers' markets for they indicate primary motivations to attend. It also provides guidelines to farmers' markets managers in their efforts to meet attendees' expectations. The second essay used an ordered logistic model to analyze consumer preferences for eight fresh produce features. These features are product variety, quality, appearance, pricing, local, organic, freshness, and knowledge of local growers. Findings show that consumer preferences are strong for product quality, freshness, local and organic production. Policy makers can use results from this essay to provide necessary assistance to farmers to feature their products based on consumers' preferences. Health-related policy makers can use the results to implement programs aimed at increasing fresh produce consumption. The last essay used a multinomial logistic, conditional and ordinary least squares models to respectively investigate consumer preferences for differentiated fresh produce, willingness to pay, and stated demands for green peppers, cucumbers, and yellow squash. Comparison between preferences before and those after information about production and place of production was also done. Results demonstrate that consumer willingness to pay and the probability of purchasing each of the three products grown conventionally in Utah overweight those for either organically or conventionally grown of unknown origin. This essay provides information pertaining to produce differentiation through labels. The information has significant impact on preferences for conventionally grown local produce and negative effect on conventionally grown fresh produce of unknown origin. Green peppers, cucumbers, and yellow squash are ordinary goods with inelastic stated demands. Produce growers can use results from this essay to adopt production practices to meet consumer preferences. Results are useful to policy makers in enforcing local and organic certification regulations. They can also be used for pricing and marketing strategies.

No description available.

This project examines whether there is a direct link between respiration and the rate of senescence of fresh produce. Treatments that increase the storage life of fresh products, such as cooling, modified atmospheres and semi-permeable coatings, often decrease respiration rates. This suggests that it may be possible to assess the effectiveness of a specific storage treatment in terms of its effect on reducing respiration. If this is so, total respiration during storage should sum to a constant regardless of changes in the storage conditions. Such an equivalence between 'respiration life' and storage life has been demonstrated in only a few cases. Respiration data from a wide range of published work was analysed from the viewpoint of testing this hypothesis. In general, the results were positive, with some reservations that were further investigated by experiment. In conclusion, respiration rate may be a guide to storage life for products that have clearly defined stages of senescence, and for which rots are not the primary cause of the end of acceptability. The development of the respirometer should make it possible to examine this relationship for many other commodities. However, while respiration may be a function of the rate of senescence under some circumstances, it is also affected by other factors. These include photosynthesis, attachment to the plant, and permeance to gases. Directions for future work therefore include the contribution of photosynthesis to fruit development, the effects of ethylene on respiration rates of non-climacteric fruit while attached to the plant, and interactions between ethylene synthesis and disease resistance / Doctor of Philosophy (PhD)

This work introduces technology for rapid pathogen detection using handheld optical immunoassay and wire-guided droplet PCR systems. There have been a number of cases of foodborne or waterborne illness among humans that are caused by pathogens such as Escherichia coli O157:H7, Salmonella typhimurium, Influenza A H1N1, and the norovirus. The current practices to detect such pathogenic agents are: cell/viral culturing, immunoassays, or polymerase chain reactions (PCRs). These methods are essentially laboratory-based methods that are not at all real-time and thus unavailable for early-monitoring of such pathogens. They are also very difficult to be implemented in field, preventing early detection opportunities. This dissertation is divided into three papers that present methodologies towards the expeditious detections of infectious pathogens and the miniaturization of these detection systems towards field-deployable and point-of-care applications. Specifically, the work presented focuses on two methodologies: (1) light scatter detection using immunoagglutination assays with optimized Mie light scatter parameters in a real biological matrix consisting of plant tissue, and (2) wire-guided droplet manipulations for rapid and improved sample analysis, preparation, and PCR thermocycling. Both of these methods carry a collective objective towards providing high impact technologies for addressing the issues of food-related outbreaks and overall public safety. In the first paper, the direct and sensitive detection of foodborne pathogens from fresh produce samples was accomplished using a handheld lab-on-a-chip device, requiring little to no sample processing and enrichment steps for a near-real-time detection and truly field-deployable device. The detection of Escherichia coli K12 and O157:H7 in iceberg lettuce was achieved utilizing optimized Mie light scatter parameters with a latex particle immunoagglutination assay. The system exhibited good sensitivity, with a limit of detection of 10 CFU mL⁻¹ and an assay time of <6 min. Minimal pretreatment with no detrimental effects on assay sensitivity and reproducibility was accomplished with a simple and cost-effective KimWipes filter and disposable syringe. Mie simulations were used to determine the optimal parameters (particle size d, wavelength λ, and scatter angle θ) for the assay that maximize light scatter intensity of agglutinated latex microparticles and minimize light scatter intensity of the tissue fragments of iceberg lettuce, which were experimentally validated. This introduces a powerful method for detecting foodborne pathogens in fresh produce and other potential sample matrices. The integration of a multi-channel microfluidic chip allowed for differential detection of the agglutinated particles in the presence of the antigen, revealing a true field-deployable detection system with decreased assay time and improved robustness over comparable benchtop systems. In the second paper, we demonstrate a novel method of wire-guided droplet manipulations towards very quick RT-PCR. Because typical RT-PCR assays take about 1–2 h for thermocycling, there is a growing need to further speed up the thermocycling to less than 30 min. Additionally, the PCR assay system should be made portable as a point- of-care detection tool. Rapid movements of droplets (immersed in oil) over three different temperature zones make very quick PCR possible, as heating/cooling will be made by convective heat transfer, whose heat transfer coefficients are much higher than that of conduction, the latter of which is used in most conventional PCR systems. A 30-cycle PCR of a 160 bp gene sequence amplified from 2009 H1N1 influenza A (human origin) was successfully demonstrates in 6 min and 50 sec for a very large 10 μL droplet (with additional 4 min for reverse transcription). The proposed system has a potential to become a rapid, portable, point-of-care tool for detecting influenza A. In the third paper, a wire-guided CNC apparatus was used to perform droplet centrifugation, DNA extraction, and VQ-PCR thermocycling on a single superhydrophobic surface measuring 25 mm by 55 mm and a multi-chambered PCB heater. This methodology exhibited no limitations on the complexity and configuration of procedures that it can perform, making it versatile and far-reaching in its applications. The only modification required for adding or implementing changes for a new protocol is through simple pre-defined programming. The highly adaptive and flexible system was used to execute easily pre-programmed droplet movements and manipulations for the rapid detection of Escherichia coli from PCR detection. Serial dilutions were performed to simulate a diluted field sample with a high level of accuracy. Centrifugation of the diluted sample containing E. coli demonstrated a novel approach to sample pre-treatment. Furthermore, the extraction of DNA from the sample droplet containing E. coli was also performed on the same superhydrophobic surface as the previous 2 steps, requiring less than 10 min. Following extraction, the genetic material was amplified using wire-guided droplet PCR thermocycling, successfully completing 30 cycles of Peptidase D (a long 1500 bp sequence) in 10 min. The droplet centrifugation process was determined to greatly improve the positive band intensity over the non-centrifuged sample. Thus, this work demonstrates the adaptability of the system to replace many common laboratory tasks on a single platform (through re-programmability), in rapid succession (using droplets), and with a high level of accuracy and automation.

[pt] Nas últimas décadas, a literatura sobre Gerenciamento da Cadeia de Suprimentos (GCS) tem ressaltado a necessidade de colaboração entre os diversos atores (empresas participantes) dentro da cadeia de suprimentos (CS). Assim, as empresas necessitam de novos instrumentos para monitorar não só o seu desempenho, mas também o desempenho da cadeia como um todo. O desenvolvimento da tese está formulado segundo duas óticas. A primeira, conceitual, refere-se ao tema avaliação de desempenho na cadeia de suprimentos. A segunda, gerencial, com a escolha da cadeia para o desenvolvimento da pesquisa empírica. Nesse caso optou-se pela cadeia de alimentos (frutas e vegetais) frescos e minimamente processados do Reino Unido. Para direcionar a pesquisa, dois objetivos principais foram formulados. O primeiro consiste em comparar os elementos operacionais das parcerias da cadeia de frutas e vegetais, identificados na pesquisa empírica, com os benefícios e processos de relacionamento observados na literatura. O segundo objetivo visa formular um modelo teórico de avaliação de desempenho para a cadeia de suprimentos de alimentos frescos - MADCS. Para alcançar o primeiro objetivo, uma hipótes principal, cinco hipóteses complementares e seis questões exploratórias foram formuladas e estatisticamente testadas. O segundo objetivo foi alcançado através da formulação do MADCS utilizando-se a revisão bibliográfica em conjunto com os resultados empíricos obtidos. A pesquisa amostral (survey) foi escolhida como estratégia de pesquisa, e como instrumento de pesquisa desenvolveu-se um questionário. Foram enviados 303 questionários com retorno de 99 (32%). Para o teste das hipóteses foram utilizados os seguintes testes estatísticos: análise fatorial, teste qui-quadrado, análise da variância, regressão logística e regressão linear simples. Como conclusão dos testes estatísticos tem-se que tanto os Benefícios, quanto os Processos de Relacionamento (Individuais e Conjuntos) foram parcialmente confirmados. Com relação às hipóteses complementares, três foram estatisticamente confirmadas e em duas não havia evidências estatísticas para confirmação. Na formulação do Modelo de Avaliação de Desempenho para a Cadeia de Suprimentos (MADCS) foi identificada a necessidade de incluir a avaliação dos processos de relacionamento nos modelos até então identificados na avaliação de desempenho das parcerias. / [en] Supply chain management (SCM) has emerged as an important strategic weapon for manufacturers seeking sustainable competitive advantage. As a result, collaboration between trading partners is replacing confrontation as the preferred approach to buyer-supplier relationships. The focus of SCM is the coordination and control of key business processes throughout the supply chain, within and between firms. As a result, researchers have sought to develop integrated models of supply chain management in which firms are treated as integral parts of four distinct flows - information, value-added products, funds and knowledge . This thesis has two main objectives: the first is to identify and to compare the partnership capabilities (benefits and processes) from the UK fresh produce industry with the benchmark indicators from the literature. The second one is to create a theoretical framework contributing to the theory of supply chain performance measurement. One main hypothesis, five complementary hypotheses and six exploratory questions were formulated in relartion to the primary research objective. In pursuit of the second objective a performance measurement model for fresh produce - MADCS was formulated. This model is supported by the performance measurement theory and by empirical results. A survey was choosen as the empirical research strategy. To capture the data 303 questionnaries were sent in February 2002 to UK fresh produce suppliers with turnover of more than £ 1 million. To test the hypotheses, chi-square, simple linear regression, factor analysis and logistics regression techniques were used. Overall, the results support the main hypothesis and three of the remaining sub-hypotheses. However, there results do not support the other two hypotheses.

Fresh produce is increasingly implicated in outbreaks of foodborne illness. Internalization of bacterial pathogens into produce is of particular concern as internalized pathogens are unlikely to be removed by surface sanitizers. It is therefore necessary to develop treatments that will reduce their prevalence and numbers on fresh produce. Irradiation is a penetrating nonthermal treatment that effectively eliminates bacteria. Irradiated baby spinach leaves up to 1.0 kGy showed negligible (P>0.05) changes in color, texture, vitamin C, total carotenoids, and chlorophyll content compared to non-irradiated controls throughout storage (15 days at 4oC). This research also shows that irradiation effectively reduces viable Escherichia coli cells internalized in lettuce, and that decontamination is not influenced (P>0.05) by lettuce variety. Irradiation effectively reduced the population of internalized pathogens in a dose-dependent manner (3-4 log reduction at 1.0 kGy). Microscopy images suggest that the contamination sites of pathogens in leafy vegetables are mainly localized on crevices and in the stomata. A careful design of the treatment (understanding dose distribution) will effectively eliminate pathogens while maintaining produce quality. The use of modified atmosphere packaging increased (P<0.05) the sensitivity of pathogens (Salmonella spp. and Listeria spp.) to irradiation in baby spinach leaves (up to 25%). Increasing concentration of oxygen increased (P<0.05) sensitivity of both microorganisms. Radiosensitization could be affected (P<0.05) by production of ozone, which increases with increasing dose-rate and oxygen concentration, and reducing temperatures. Antimicrobial effectiveness of various active compounds was determined against Salmonella spp. and Listeria spp. Inclusion complexes were prepared with antimicrobial compounds and -cyclodextrin. The effectiveness of the microencapsulated compounds was tested by spraying them on the surface of baby spinach leaves inoculated with Salmonella spp. The increase in radiosensitivity (up to 40%) varied with the antimicrobial compound. Spherical poly (DL-lactide-co-glycolide) (PLGA) nanoparticles with entrapped eugenol and trans-cinnamaldehyde were synthesized for future antimicrobial delivery applications. All loaded nanoparticles proved to be efficient in inhibiting growth of Salmonella spp. and Listeria spp. The entrapment efficiency for eugenol and trans-cinnamaldehyde was 98% and 92%, respectively. Controlled release experiments (in vitro at 37oC for 72 hrs) showed an initial burst followed by a slower release rate of the antimicrobial entrapped inside the PLGA matrix.