Duas formulações de queijo de leite cru e fermento endógeno foram produzidas e avaliadas após 30, 60 e 180 dias de armazenamento em câmaras de maturação de dois laticínios do Sudoeste do Paraná foram estudadas para avaliar as características, como uma das etapas de desenvolvimento de um queijo típico regional. A produção foi acompanhada desde a elaboração do fluxograma de processamento, coleta das amostras de queijo para realização de análises de proteína, lipídeos, umidade, cinzas, carboidratos, extrato seco total, gordura no extrato seco, calorias; atividade de água, textura instrumental (dureza, adesividade, elasticidade, coesividade, mastigabilidade e resiliência), cor (CIE Lab), análises microbiológicas (contagem de coliformes totais, contagem de coliformes termotolerantes e contagem de Staphylococcus coagulase positiva e pesquisa de Salmonella spp.); teste de aceitação relacionada às características sensoriais (cor, aparência, odor, textura, sabor) e intenção de compra. Essa pesquisa contribuiu com informações relevantes ao processo produtivo, tais como, a constatação da viabilidade do fermento lático liofilizado elaborado a partir das bactérias ácido láticas isoladas do leite da mesorregião do Sudoeste do Paraná e cujos resultados das análises dos queijos indicaram similaridade entre as formulações, no que se refere a caracterização física e físico-química, além de boa qualidade microbiológica, onde as discrepâncias entre as amostras dos laticínios não foram percebidas sensorialmente pelos provadores. Ajustes na padronização relacionados ao controle de qualidade tecnológica serão um fator de extrema importância para o sucesso das empresas e pequenos produtores envolvidos no projeto e que se dispõem a produzir o Santo Giorno, um queijo fino, com o grande diferencial de agregar características da região, com elevado padrão de qualidade higiênico-sanitária e com indicativos de grande aceitação pelo consumidor. / Two cheese formulations made from raw milk and endogenous yeasts with 30, 60 and 180 days of maturation in two dairy Paraná Southwest were studied to evaluate their quality through physical, physical-chemical, microbiological and sensorial characteristics, as one of the stages of development of a typical regional cheese. The production was accompanied from designing the flowchart processing, where the samples were collected to perform the analysis of proteins, lipids, moisture, ash, carbohydrates, total solids, fat in dry matter, calories; water activity, instrumental texture (hardness, adhesiveness, springiness, cohesiveness, resiliency and chewiness), instrumental color (CIE Lab); microbiological quality was assessed searching for total and thermotolerant coliforms, coagulase positive staphylococci and Salmonella spp.; the acceptance related to sensory characteristics of color, appearance, flavor, texture, taste and purchase intent was evaluated through the structured hedonic scale. This research contributed information relevant to the production process, such as the realization of the viability in freeze-drying lactic acid bacteria yeast isolated from milk in the Southwestern Mesoregion of Parana and the results of the analysis of the cheese showed similarity between formulations, regarding the physical, physical-chemical characterization, moreover good microbiological quality, where the differences between samples of dairy products were not perceived by sensory panelists. Adjustments in standardization related to technological quality control is an extremely important factor for the success of dairy companies and small producers involved in the project and that they have the option of producing the Santo Giorno, a fine cheese, with the great advantage of adding features of region, with high standard of sanitary conditions and with great consumer acceptance of indicative.

Com o objetivo de estabelecer associações entre as características dos consumidores de produtos lácteos com a preferência pelo produto lácteo formal ou informal, as razões para essa preferência, o hábito de fervura do leite dentre os consumidores de informal, os principais produtos lácteos consumidos, o conhecimento sobre as doenças transmitidas pelo leite e derivados e o significado do carimbo do Serviço de Inspeção, para que pudessem servir de base para ações futuras de intervenção para a redução do consumo de informais, realizou-se um levantamento utilizando um questionário semi-estruturado, com 29 questões, aplicado a 465 consumidores em diferentes pontos comerciais do município de Jacareí, no período de novembro de 2004 a fevereiro de 2005. Os resultados mostraram associação entre o consumo do produto informal e as características: sexo masculino, local de moradia zona rural, renda familiar acima de R$ 1.040,00, mais de 4 pessoas morando no domicílio, compra de ambulantes, compra na zona rural e o conhecimento sobre a possibilidade do produto lácteo poder causar doenças. Associada ao consumo de produtos formais esteve apenas a variável compra em supermercado.Os produtos lácteos informais mais consumidos foram o leite fluido, queijo minas frescal, manteiga e iogurte. Dos consumidores de leite fluido 7,4% consomem leite informal sem ferver. As principais razões para o consumo do informal foram: ser mais puro, mais fresco, mais barato, mais forte, ter confiança em quem vende o produto, não ter diferença do industrializado, ser mais saudável e mais saboroso. Para os derivados formais, obteve-se primeiro a praticidade, seguida pela segurança ou procedência, higiene, não encontrarem do produtor, ser tratado ou testado, o costume, o sabor e o preço. Aproximadamente 17% dos consumidores alegaram procurar pelos carimbos da Inspeção na embalagem ao comprar leite ou derivados, no entanto nenhum consumidor se lembrou dos carimbos quando perguntados o que observavam na embalagem no ato da compra de produtos industrializados. Os meios de divulgação de informação escolhidos, em ordem de freqüência, foram: TV, rádio e através das escolas do ensino fundamental. Conclui-se que o consumo de produto lácteo informal independe de qualquer das variáveis estudadas, embora haja maior freqüência de consumo de informais entre homens, entre as pessoas que moram na zona rural, famílias com renda mais alta, maior número de pessoas por domicílio, quando há compra de ambulantes ou na zona rural e entre as pessoas que alegam ter conhecimento de que o leite transmite doenças; 7,4% dos entrevistados estão expostos ao risco de contrair alguma zoonose ou outra doença pelo consumo de leite cru sem ferver. A população precisa ser esclarecida sobre as reais diferenças entre os produtos industrializados e os informais, bem como sobre os órgãos que atestam a qualidade dos alimentos. A redução do risco será alcançada quando governo e indústria trabalharem, sistemática e continuamente, para mudar paradigmas e motivar mudança de hábitos / Intending to establish associations between dairy product consumers’ characteristics and the preference for a formal or informal dairy product, the reasons for this preference, the habit of boiling the milk among the informal product’s consumers, the main consumed dairy products, knowledge about milk and dairy product borne diseases and the meaning of the Inspection Service’s seal, so they could be a base for future intervention actions to reduce informal product consumption, a survey was carried out using a 29-question semi-structured questionnaire applied to 465 consumers at different points of sale in the city of Jacareí-SP-Brazil from November 2004 to February 2005. The results showed an association between the consumption of the informal product and the following characteristics: male, rural area residence, family income above R$ 1,040.00, more than 4 residents, purchase from street vendors, purchase in the rural area and knowledge that the dairy product can cause diseases. Only the supermarket purchase variable was associated to formal product consumption. The most consumed informal dairy products were: liquid milk, fresh white cheese, butter and yogurt. 7.4% of the liquid milk consumers consume raw milk without boiling it. The main reasons for consuming the informal dairy product were: for being purer, fresher, cheaper, stronger, for trusting who sells the product, for not being different from the industrialized product and for being healthier and tastier. For the formal dairy products, first came practicality, then safety or origin, hygiene, not finding from the producer, being treated or tested, custom, taste and price. About 17% of the consumers said they look for the Inspection seals on the package when they buy milk or dairy products; however no consumer remembered the seal when asked what they observed on the package upon buying industrialized products. The chosen disclosure means, in order of frequency were: TV, radio and through middle schools. The conclusion is that the consumption of informal dairy products does not depend on any of the studied variables, although there is a higher frequency of informal dairy product consumption among men, among those who live in the rural area, families with higher income, higher number of residents per house, when purchased from street vendors and in the rural area and among people who say they know that milk spreads diseases; 7.4% of those interviewed are exposed to the risk of getting some zoonosis or other disease by consuming raw not-boiled milk. The population must be informed about the real differences between industrialized and informal dairy products, as well as about the authorities that certify food quality. Risk reduction will be reached when the government and industry systematically and continuously work to change paradigms and motivate habit changes

Caracterização molecular e susceptibilidade antimicrobiana de linhagens de Listeria monocytogenes isoladas de alimentos no RS Mestranda: Fernanda De Nes Orientador: Jeverson Frazzon Listeria monocytogenes é o microrganismo causador de listeriose, uma doença infecciosa adquirida através do consumo de alimentos contaminados e que afeta principalmente pessoas com o sistema imunológico comprometido como gestantes e recém nascidos. É um microrganismo ambiental, podendo ser encontrado no solo, água e alimentos como vegetais, produtos cárneos, leites crus ou mal pasteurizados, queijos, entre outros. São bactérias invasivas e possuem facilidade para penetrar na célula hospedeira. O ataque a essas células é intermediado pelas internalinas, que são proteínas associadas a genes de virulência. As internalinas InlA e InlB, codificadas pelo gene inlAB, são proteínas associadas com a invasão e internalização da bactéria na célula hospedeira. Este trabalho teve o objetivo de caracterizar um total de 19 linhagens de Listeria monocytogenes, sorovares 1/2b, 1/2a, 4b, 4c, isoladas de produtos lácteos do Rio Grande do Sul. Para a caracterização molecular foram utilizadas as técnicas moleculares de Amplificação Randômica do DNA Polimórfico (RAPD) e Análise por Enzimas de Restrição (PCRREA), com a amplificação de um segmento de 2916 pb que incluem partes dos genes inlA e inlB, utilizando para isso duas enzimas de restrição AluI e EcoRI. As técnicas moleculares utilizadas foram ferramentas úteis para caracterizar as linhagens de Listeria monocytogenes isoladas de produtos lácteos do Rio Grande do Sul. Ainda, foi observado o perfil de resistência antimicrobiana desses microrganismos frente a vários antimicrobianos, das amostras analisadas todas foram susceptíveis aos antimicrobianos testados. / Listeria monocytogenes is a microorganism which causes listeriosis, an infection disease caused by consuming contaminated food and it mainly affects individuals with the immune system at risk like pregnant women and newborn infants. It is an environmental microorganism, being found in soil, water and food like vegetables, meat products, unpasteurized milk and cheese. They are invasive bacteria which have special facility to penetrate the host cell. The attack to those cells is carried out by internalins, which are proteins associated with virulence genes. The InlA and InlB internalins, codified by inlAB gene, are proteins associated with the invasion and internalization of the bacteria in the host cell. This work aimed at categorizing a total of 19 strains of Listeria monocytogenes, 1/2b, 1/2a, 4b and 4c serovars, isolated from dairy products from the State of Rio Grande do Sul. For the molecular categorization, it was used the molecular techniques of Polymorphic DNA Random Amplification (RAPD) and Restriction Enzymatic Analysis (PCR-REA), with the amplification of a segment of 2916 pb which includes part of inlA and inlB genes, using for that purpose two restriction enzymes, AluI and EcoRI. The molecular techniques applied were useful tools to categorize strains of L. monocytogenes isolated from dairy products of the State of Rio Grande do Sul. Furthermore, it was observed the antimicrobial resistant profile of those microorganisms in front of various antimicrobials. All of the analyzed samples were susceptible to tested antimicrobials.

Submitted by Geandra Rodrigues (geandrar@gmail.com) on 2018-07-13T14:13:42Z No. of bitstreams: 1 carolinacarvalhoramosviana.pdf: 2071193 bytes, checksum: ced9ed600a8408dfa84aa8a442fdff6f (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2018-07-16T17:33:13Z (GMT) No. of bitstreams: 1 carolinacarvalhoramosviana.pdf: 2071193 bytes, checksum: ced9ed600a8408dfa84aa8a442fdff6f (MD5) / Made available in DSpace on 2018-07-16T17:33:13Z (GMT). No. of bitstreams: 1 carolinacarvalhoramosviana.pdf: 2071193 bytes, checksum: ced9ed600a8408dfa84aa8a442fdff6f (MD5) Previous issue date: 2018-03-28 / Este trabalho tem como objetivo geral a utilização da Espectroscopia na região do Infravermelho Médio, aliada à calibração multivariada (PCA e PLS) para caracterizar e quantificar a composição majoritária de fórmulas infantis. Foram avaliadas 20 marcas comercializadas em Juiz de Fora (MG), de quatro grandes indústrias do ramo. Determinou-se a composição majoritária das amostras (teor de lipídios, proteína verdadeira, carboidratos, umidade, sólidos totais e cinzas) por meio de métodos físico-químicos, em duplicata, de acordo com metodologias oficiais de análise, sendo que os resultados, em geral, atendem a legislação vigente. Em acréscimo, foi realizada a avaliação espectroscópica das formulações, na região MIR de 4000 cm-1 a 400 cm-1. Utilizando-se de ferramentas estatísticas, foi possível interpretar os espectros gerados e caracterizar a composição das fórmulas infantis testadas, em comparação às principais alegações descritas no rótulo e da literatura. As proposições sugeridas foram confirmadas pelo comportamento das amostras destas frente à Análise dos Componentes Principais (PCA), e a partir disto, pode-se dizer que a espectroscopia FT-MIR-ATR foi capaz de caracterizar as diferentes formulações testadas, quando aliada a estatística multivariada. Já em relação à Regressão por Mínimos Quadrados Parciais (PLS), somente foi encontrada correlação entre os dados físico-químicos e os espectros MIR no intervalo entre 1400 cm-1 e 1000cm-1, e por isso, este foi utilizado para as previsões dos valores analíticos. Por ser a região característica da absorção de carboidratos, o modelo apresentou os melhores resultados na predição do teor deste componente, com perfil de curva de calibração e ao mesmo tempo, apresentou predições ruins para o restante dos atributos testados. Sugere-se que o modelo possui potencial para as predições físico-químicas, em especial para carboidratos, caso sejam efetuadas curvas de calibração para este tipo de matriz alimentar. / This work focuses on the use of Fourier Transformed Mid Infrared Spectroscopy (FT-MIR) coupled to Attenuated Total Reflectance (ATR), combined with multivariate calibration as Principal Component Analysis (PCA) and Partial Least Squares (PLS) to characterize and quantify the majority composition of infant formulas. Twenty trademarks marketed in Juiz de Fora (MG) were evaluated from four different industries. The majority composition of the samples (lipid content, true protein, carbohydrates, moisture, total solids and ashes) was determined by physicochemical methods, in duplicate, according to official analysis methodologies. The results, in general, comply with current legislation. On the other hand, the spectroscopic evaluation of the formulations was performed in the MIR region from 4000 cm-1 to 400 cm-1. Using statistical tools, it was possible to interpret the generated spectra and characterize the composition of the infant formulas tested, in comparison to the main claims described in the labels and in the literature. The suggested propositions were confirmed by the behavior of these samples when compared to PCA. It can be said that FT-MIR-ATR spectroscopy was able to characterize the different formulations tested, when allied to multivariate statistics. In relation to the Regression by PLS, only a correlation was found between physicochemical data and MIR spectra in the interval between 1400 cm-1 and 1000 cm-1, and therefore, it was used for the predictions of the analytical values. Because it is the characteristic region of carbohydrate absorption, the model presented the best results in the prediction of the content of this component, with a calibration curve profile and at the same time presented bad predictions for the rest of the attributes tested. It is suggested that the model has potential for physicochemical predictions, especially for carbohydrates, if calibration curves are made for this type of food matrix.

Made available in DSpace on 2014-08-20T13:57:57Z (GMT). No. of bitstreams: 1 Dissertacao_Ludmila_Correa_Muniz.pdf: 1540349 bytes, checksum: 8a2ad55f87ded50b0d6530d557bd5c06 (MD5) Previous issue date: 2010-12-12 / This study describes the prevalence of daily milk intake and the consumers profile, as well as the types of milk taken by the population aged ≥20 years old from Pelotas-RS. Through a cross-sectional study, of population base, with a representative sample from the city, 2,732 individuals were interviewed. The prevalence of milk daily intake was of 34,1%, being higher among women (37,3%), elderly people (55,9%), higher schooling individuals (42,3%) and of higher economic level (45,5%). Among the consumers, 97,6% take cow s milk and, 75,5%, full-fat milk. The average milk intake was of 1,8 (DP±1,2) portion/day, in which 87,6% take less than three daily portions. Around 26% of the individuals mentioned not taking any kind of milk and, among these, only 18,7% daily take dairy products. The main reason for not consuming milk was the fact that the individual does not like it. The skim milk intake in order to replace the full-fat milk should be stimulated. Besides that, milk should be properly taken in terms of frequency and amounts. / Este estudo descreve a prevalência de consumo diário de leite e o perfil dos consumidores, bem como os tipos de leite ingeridos pela população com idade ≥20 anos de Pelotas-RS. Por meio de estudo transversal, de base populacional, com amostra representativa da cidade, foram entrevistados 2732 indivíduos. A prevalência de consumo diário de leite foi de 34,1%, sendo maior entre mulheres (37,3%), idosos (55,9%), indivíduos com maior escolaridade (42,3%) e de maior nível econômico (45,5%). Dentre os consumidores, 97,6% ingerem leite de vaca e, 75,5%, com teor de gordura integral. O consumo médio de leite foi de 1,8 (DP±1,2) porção/dia, sendo que 87,6% ingerem menos de três porções diárias. Aproximadamente 26% dos indivíduos referiram não ingerir nenhum tipo de leite e, destes, apenas 18,7% consomem diariamente derivados do leite. O principal motivo para o não consumo de leite foi o fato do indivíduo não gostar do alimento. A ingestão de leite desnatado em substituição ao consumo de leite integral deve ser estimulada. Ademais, leite deve ser consumido em frequência e quantidade adequadas.

Les évaporateurs à flot tombant (EFT) sont largement utilisés dans les industries chimiques, de la réfrigération, du raffinage du pétrole, et alimentaires. Dans l'industrie laitière, les EFT sont appliqués pour la concentration de solutions avant l'étape de séchage. Malgré l'importance économique du procédé d'évaporation sous vide dans la fabrication de produits laitiers déshydratés, la connaissance du procédé est essentiellement empirique. Des recherches visant à améliorer l'efficacité du procédé sont donc nécessaires. L'objectif de ce projet de doctorat est de caractériser expérimentalement un EFT lors de la concentration de produits laitiers, par des approches thermo et hydro-dynamiques, afin d'étudier les interactions entre les propriétés des produits et les paramètres opérationnels. Un évaporateur à flot tombant, simple effet, à l’échelle pilote, qui décrit le même processus que celui à l'échelle industrielle, d'un point de vue hydrodynamique, a été instrumenté et utilisé pour établir les bilans massiques et énergétiques. La capacité évaporatoire et le coefficient global de transfert de chaleur ont été calculés à partir des données expérimentales. Une méthodologie pour la détermination expérimentale des fonctions distribution des temps de séjour (DTS) a été développée. En effet, les fonctions de DTS fournissent des informations essentielles sur l'écoulement des produits lors de la concentration dans un EFT. L'augmentation de la concentration, du débit massique et de la distance parcourue par le produit entraîne une augmentation de la dispersion des particules dans le flux. Ces fonctions ont été modélisées par une combinaison de réacteurs en cascade, parfaitement agités. D’après l'interprétation de ce modèle, deux flux, un principal et un secondaire, correspondant à deux couches superposées de produit circulant à travers des tubes d'évaporateur, a été proposé. La méthodologie développée pour le calcul des fonctions de DTS a été appliqué pour la concentration de produits laitiers (lait écrémé, lactosérum doux et acide). Par la suite, l'étude a été étendue à la formation de l'encrassement pendant la concentration par évaporation sous vide. Il a été montré que le temps de séjour moyen était plus sensible pour identifier l'encrassement que le coefficient global de transfert de chaleur et la capacité évaporatoire. Ainsi, cette étude a souligné le rôle crucial de l’importance de la caractérisation des EFT sous vide afin d’en améliorer leurs performances et la qualité des produits qui en sont issu. / Falling film evaporators (FFE) are widely used in the chemical, refrigeration, petroleum refining, desalination and food industries. In the dairy industry FFE is applied for the concentration of solutions prior to the drying step. Despite the economic importance of the vacuum evaporation process in the manufacture of dairy dried products, the knowledge about the process is mostly empirical. Research aiming to improve the efficiency of the process is therefore necessary. The objective of this PhD project was to characterize experimentally a FFE during the concentration of dairy products by means of thermodynamic and hydrodynamic approaches, in order to study the interactions between the products properties and the operating parameters. A pilot-scale, single-stage falling film evaporator that describes the same process as that of an industrial scale from a hydrodynamic point of view was instrumented and used to establish the mass and energy balances. The evaporation rate and the overall heat transfer coefficient were calculated from the experimental data to follow up the process. A methodology for the determination of the experimental residence time distribution (RTD) functions was developed. RTD functions provide global information about the flow of the products during concentration in a FFE. Increasing of the concentration of skim milk, mass flow rate and the distance covered by the product resulted in an increase in the dispersion of the products particles. The experimental RTD functions were modelled by a combination of two perfectly mixed reactor tanks in series. From the interpretation of this model, two different flows, a main and a minor flow, were identified. The RTD methodology developed on skim milk was applied to sweet whey and lactic acid whey and the study was extended to the formation of fouling during a 5-hour concentration. The mean residence time was more sensitive to identify fouling than the overall heat transfer coefficient and the evaporation rate. This study emphasized the crucial role of process characterization to improve the performance of FFE and product quality.

Submitted in fulfilment of the requirements for the Degree of Doctor of Technology: Public Management, Durban University of Technology, 2017. / Disasters are on the increase globally with devastating effects. The devastation caused by these disasters in various countries highlights the need for increased commitment and investment, by government and various stakeholders, in disaster risk reduction. This study investigated disaster risk reduction strategies in Zimbabwe’s dairy supply chains. The study was initiated on the premise that Zimbabwe is at high risk and vulnerable to natural and man-made hazards. The study is set in the backdrop of declining output across all agricultural sectors evident particularly in the dairy farming sector that has seen inadequate supply of raw milk and dairy products by local producers in Zimbabwe. This study therefore sought to assess the collaborative strategies by government, dairy organisations and dairy supply chain stakeholders to reduce disaster risks in the dairy industry. The study employed a mixed-method approach (qualitative and quantitative) to investigate collaborative disaster risk reduction strategies used by dairy supply chain stakeholders to avoid supply chain disruptions. The study used a sample size of 92 dairy farmers, from major milk producing regions of Zimbabwe, for the questionnaire. The Cronbach alpha test for reliability showed a reliable questionnaire. Furthermore, the study used information from key informants, 30 retailers and 20 dairy officers for one-on-one interviews. Quantitative data was analysed using STATA (version 13). OLS regression analysis was done and results were compared with those of the Tobit models as a test for robustness of the results. Qualitative data was analysed using thematic analysis derived from observations and interviews and descriptive statistics presented in tables and bar charts. Notable in the literature reviewed is lack of coordination amongst stakeholders in strategies to reduce disaster risks in dairy supply chains in Zimbabwe. This study adopted a collaborative proactive framework and tested it as a strategy to reduce disaster risks in dairy supply chains. The study gives four major findings. Firstly, dairy supply chains in Zimbabwe were exposed to a number of risks which are: international competition, competition from local giants, financial risks, political risks, technological risks, environmental risks and production risks. Secondly, findings from regression analysis indicated that an overall index of disaster risks significantly influenced job losses, food security, milk productivity and growth of ventures in dairy businesses. Thirdly, there were isolated cases of planned coordination by stakeholders in the industry to reduce the negative effects of disasters across the supply chain. There was collaboration among dairy farmers, processors, NGOs, and government departments of agriculture and environment. Fourthly, an index of collaborative strategies regressed against dependent variables of variables of supply chain cost, lead time milk sales, and variety and quality of milk demonstrated that collaborative strategies in dairy supply chain significantly influenced supply chain costs and variety and quality of milk and milk products. It is expected that the study will assist government in the formulation of public policies for the dairy sector leading to improved access to high quality raw milk and milk products for consumers thus resulting in improved nutrition and food security for the people of Zimbabwe. Policy recommendations highlight that instead of the current maximum of the 5 year lease given to white commercial farmers, the government should consider issuing out long term leases in order to protect long-term investment in dairy projects. Government should, therefore, create an enabling environment for stakeholder partnerships in the dairy sector. / D

Le développement de simulateurs de procédés alimentaires est limité par le manque d’outils permettant de prédire les propriétés physicochimiques (pH, aw, Eh) dans les aliments. Les aliments sont généralement des milieux très complexes contenant un nombre élevé de constituants (eau, solvants organiques, solides dissous, gaz dissous, espèces ioniques, macromolécules), et ces propriétés sont essentielles pour caractériser leur qualité technologique, sanitaire et organoleptique. Cependant, elles évoluent au cours d’un procédé de transformation ou de conservation. La prédiction de ces propriétés physicochimiques passe par la détermination de potentiels chimiques. Une approche de modélisation basée sur la thermodynamique est utilisée pour prédire l’évolution du pH et de l’aw de produits carné et produits laitiers dans certaines conditions rencontrées en industrie alimentaire. En s’appuyant sur le modèle ULPDHS développé par Achard en 1992 pour les milieux liquides, ce travail a nécessité la création de molécules fictives à ayant le même comportement que les aliments modélisés. La cohérence entre les données expérimentales et les données prédites est satisfaisante, le modèle thermodynamique permet de prédire correctement le pH et l’aw des différents milieux étudiés. Cependant l’intégration du modèle thermodynamique dans un simulateur de procédé nécessite la création d’un réseau de neurone mimétique du modèle thermodynamique. En conséquent a été développé un réseau de neurones dont les sorties sont identiques aux sortie du modèle thermodynamique. Ainsi il est possible d’intégrer les résultats du modèles thermodynamique dans un simulateur de procédé sans trop rallonger les temps de simulations. Les résultats obtenus dans ce travail peuvent être une aide importante à la formulation de nouveaux produits. Le modèle étant entièrement prédictif, il est possible de déterminer l’effet d’une modification de composition de l’aliment sur le pH et l’aw. / The development of food process simulators is actually limited by absence of tools that can predict de evolution of the physical-chemical properties (pH, aw, Eh) in food. Food are generallymulticomponent medias (including water, organic solvents, dissolved solids, dissolved gases, ionic species, macromolecules), and these properties are essential to characterize technological, sanitary and organoleptic qualities. However, these physical-chemical properties change during transformation or preservation process. The prediction of these properties requires the determination of chemical potentials. Thermodynamic approach is used to predict pH and water activity of meat and dairy products in different condition encountered in the food industry. Based on the model ULPDHS developed by Achard in 1992 for liquid medias, this work required the creation of fictive molecule who have the same behavior as modeled food. Consistency between the experimental data and the predicted data is very satisfactory, the thermodynamic model correctly predict the pH and aw of different products studied. The integration of the thermodynamic model in a process simulator requires the creation of a mimetic neural network. Therefore, was developed a neural network whose outputs are identical to the output of the thermodynamic model. So it is possible to integrate the results of thermodynamic models in a process simulator without too lengthen the time simulations. The results obtained in this work can be an important aid to the formulation of new products. The model is completely predictive and it is possible to determine the effect of a change in the composition of the feed on the pH and aw.

Bacillus cereus is a group of ubiquitous facultative anaerobic spore forming Gram-positive rods commonly found in soil. It has been detected and implicated in several contaminated food products and raw milk in dairy farms and it causes foodborne gastroenteritis by producing several toxins. This study is aimed at characterizing virulence determinants of B. cereus from cow‟s raw milk. A total of 400 raw milk samples were collected in Fort Hare Dairy Trust and Middledrift Dairy Farm; and cultured on Polymyxin pyruvate Egg-Yolk Mannitol Bromothymol Agar (PEMBA) for 48 hours at 37°C. DNA was isolated from the isolates and 16S rDNA was amplified and sent to Central Analytical Laboratory for sequencing. The gyrB gene of B. cereus was also used to confirm the identity of the isolates. Antibiotic susceptibility profiles of the isolates together with virulence genes were investigated. Multilocus Sequence typing was used to investigate the genetic relatedness of some selected isolates. Furthermore, spores of the isolates were produced, harvested and their concentrations determined. All (100%) of the isolates were identified as having a 96-99% similarity to B. cereus, B. thuringiensis and B. anthracis using sequencing; while gyrB gene was observed in all (100%) of the isolates. Three virulence genes nheA, nheB, nheC encoding for non haemolysin enterotoxin were amplified in all (100%) the isolates. All (100%) of the isolates were susceptible to doxycycline, gentamycin, tetracycline, ciprofloxacin, chloramphenicol and streptomycin. Resistance to rifampicin and penicillin G was predominant with equal rate of 100%, while susceptibility to erythromycin, clindamycin and doxycycline ranged from 60% to 100%. The selected isolates were related and are descendants of the same ancestor. All (100%) the isolates produced spores. The B. cereus isolates contain virulence genes, has multiple antibiotic drug resistance and produce spores, which poses a health risk to the public and cannot be used as probiotics.

El presente estudio tiene como propósito diseñar un modelo de gestión de inventarios que reduzca los quiebres de stock de productos en una empresa “retail” valorada a nivel Nacional para que no genere desabastecimiento de artículos lácteos en las góndolas. No todos los productos de las marcas están en las góndolas, en particular se va a estudiar el caso de los productos lácteos. La propuesta de solución consiste en un modelo de gestión de inventarios integrando el CPFR. Se utilizará métodos de pronóstico que permite determinar la demanda, administración de inventarios para establecer los parámetros adecuados por categoría y la colaboración horizontal en la producción y en la venta al por menor o CPFR que tiene como finalidad la satisfacción de las necesidades del consumidor con dirección frontal en la cadena de distribución de suministro y el ajuste de los pronósticos de la demanda calculados considerando todos los factores internos y externos que la puedan afectar. / The purpose of this study is to design an inventory management model that reduces product stock breaks in a "retail" company valued at the National level so that it does not generate shortages of dairy items in the shelves. Not all the products of the brands are in the gondolas, in particular the case of dairy products will be studied. The solution proposal consists of an inventory management model integrating the CPFR. Forecasting methods will be used to determine demand, inventory management to establish the appropriate parameters by category and horizontal collaboration in production and retail or CPFR that aims to meet the needs of the consumer with direction front in the supply distribution chain and adjusting demand forecasts calculated considering all internal and external factors that may affect it. / Trabajo de investigación