The purpose of this study was to compare the nutrient content of a new instant baby food product to jar baby food of similar product formulation. Instant and jar "Vegetable and Beef" and "Bananas" products processed in 1985 and 1987 were analyzed for available lysine, vitamin B-6 and pyridoxyllysine content. The available lysine content of 100 grams of baby food was found to be higher in the instant products, but when adjusted for protein content, available lysine was higher in the jar products. This indicates that drum-drying used for the instant products is more detrimental in regard to lysine availability than retorting. The vitamin B-6 content of the instant products was found to be higher than that of the jar products. However, due to the addition of ingredients with little or no vitamin B-6 content to the jar products, no conclusion about processing effects on vitamin B-6 content can be made. Products processed in 1985 tended to be lower in nutrient content than the products processed in 1987. Pyridoxyllysine, a compound thought to affect vitamin B-6 bioavailability, could not be detected in any of the baby foods, either by amino acid or HPLC analysis. The instant products were found to be at least equal to the jar products with regard to available lysine and vitamin B-6 content. All products also appear to provide sufficient amounts of these nutrients to infants less than one year of age. / Master of Science

Thesis (PhD)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: Background: Synbiotics, probiotics and prebiotics are being added to infant formula. This study was an in-depth evaluation of research on infants fed infant formula containing synbiotics, probiotics or prebiotics and was carried out in two phases. Phase one included two systematic reviews that assessed if synbiotics, probiotics or prebiotics led to improved growth and clinical outcomes in formula fed full term and preterm infants. Phase two included two studies: A systematic review compared the methodological quality and outcomes of industry and non-industry sponsored randomized controlled trials (RCTs) and a descriptive study evaluated how the food industry applies the knowledge and evidence gained from probiotics, prebiotics or synbiotics research in infants. The research questions were: Does the consumption of probiotics, prebiotics or synbiotics supplemented infant formula lead to improved clinical outcomes in infants? Is there an association between source of funding and methodological quality, clinical outcomes and author’s conclusions in trials using probiotics, prebiotics or synbiotics supplemented formula in infants? Does the food industry use the evidence gained through probiotics, prebiotics and synbiotics research trials on infants for the benefit of the general paediatric population? The hypotheses were: Consumption of probiotics, prebiotics or synbiotics by infants leads to improved clinical outcomes; The source of funding in research trials using probiotics, prebiotics or synbiotics supplemented formula in infants is associated with outcomes in favour of the sponsor’s products and authors’ conclusions; Methodological qualities of non-industry sponsored trials are equivalent to industry sponsored trials; Evidence gathered through probiotics, prebiotics and synbiotics research is implemented by the food industry. Methods: Phase one: Both systematic reviews on preterm and full term infants: Cochrane methodology was followed using RCTs which compared preterm or full term formula containing probiotics, prebiotics or synbiotics to conventional infant formula with / without placebo among healthy preterm or full term infants. The mean difference (MD) and corresponding 95% confidence intervals (CI) were reported for continuous outcomes, risk ratio (RR) and corresponding 95% CI for dichotomous outcomes. Phase two: In the systematic review, Cochrane methodology was used to assess the risk of bias of included RCTs. Association between source of funding and risk of bias, clinical outcomes and conclusions were assessed. In the descriptive study, all listed companies that manufacture infant food products with added synbiotics, probiotics or prebiotics for infants were identified and invited to participate. A letter of invitation was sent and if they expressed willingness to take part in the study, a questionnaire with a written consent form was sent. Descriptive statistics and associations between categorical variables were to be tested using a Chi-square test. Results: Phase one: Review on preterm infants: 8 studies were included. Probiotics increased stool frequency with no effect on other clinical outcomes. Prebiotics increased stool frequency and bifidobacteria counts only. Review on full term infants: 25 studies were included. Synbiotics improved stool frequency but had no effect on other clinical outcomes. Probiotics did not have an effect on any clinical outcome. Prebiotics increased weight gain and stool frequency with no effect on other outcomes. Phase two: Systematic review: 67 studies were included, majority were funded by food industry. There was no significant association between the source of funding and four domains (sequence generation, allocation concealment, blinding, selective reporting), majority of reported clinical outcomes or authors’ conclusions. Source of funding was significantly associated with two domains (incomplete outcome data, free of other bias), antibiotic use and conclusions on weight gain. Descriptive study: 25 companies were identified and invited to participate. No company agreed to participate in the survey for different reasons. Conclusions Phase one: Review on preterm infants: There is not enough evidence to state that supplementation with probiotics or prebiotics results in improved growth and clinical outcomes in exclusively formula fed preterm infants. Review on full term infants: There is not enough evidence to state that supplementation of term infant formula with synbiotics, probiotics or prebiotics does result in improved growth or clinical outcomes in term infants. There is no data available to establish if synbiotics are superior to probiotics or prebiotics. Phase two: Systematic review: In RCTs on infants fed infant formula containing probiotics, prebiotics or synbiotics, the source of funding does not influence majority of outcomes in favour of the sponsors’ products. More non-industry funded research is needed to further assess the impact of funding on reported clinical outcomes and authors’ conclusions. Descriptive study: Due to companies refusing to participate in this study, no conclusion could be drawn on how the food industry applies evidence gained through probiotics, prebiotics or synbiotics research on infants. More transparency is needed from the infant formula manufactures on how they apply the evidence gained from probiotic, prebiotic or synbiotic research on infants. / AFRIKAANSE OPSOMMING: Agtergrond Synbiotika, probiotika en prebiotika word gereeld by baba formule gevoeg. Hierdie studie was 'n in-diepte evaluering van navorsing oor babas gevoed met formule melk wat synbiotika, probiotika of prebiotika bevat en is uitgevoer in twee fases. Fase een het twee sistematiese oorsigte ingesluit wat die rol van synbiotika, probiotika en prebiotika op verbeterde groei en kliniese uitkomste van formule gevoede volterm babas en vroeg gebore babas evalueer het. Fase twee het bestaan uit twee studies: 'n sistematiese oorsig wat die metodologiese kwaliteit en uitkomste van die bedryf en nie-bedryf geborgde ewekansige gekontroleerde proewe (RCTs) evalueer het, asook 'n beskrywende studie wat die kennis en toepassing van bewyse oor die effektiewiteit van probiotika, prebiotika of synbiotika in die voedsel industrie bestudeer het. Die hipotese stellings was: verbruik van probiotika, prebiotika of synbiotika by babas lei tot verbeterde kliniese uitkomste; die bron van befondsing vir synbiotics, probiotika of prebiotika navorsing beïnvloed uitkomste ten gunste van die borg se produkte; bewyse ingesamel deur middel van probiotika, prebiotika en synbiotika navorsing word geïmplementeer deur die voedselindustrie. Metodes Fase een: Beide sistematiese oorsigte op volterm en premature babas: Cochrane metodes is gevolg deur ewekansige, gekontroleerde studies wat vol termyn of premature formule met probiotika, prebiotika of synbiotika met konvensionele baba formule met / sonder plasebo onder gesonde volterm of premature babas bestudeer. Die gemiddelde verskil (MD) en die ooreenstemmende 95% vertrouensintervalle is gebruik vir deurlopende uitkomste, risiko verhouding (RR) en die ooreenstemmende 95% CI vir tweeledige uitkomste. Fase twee: In die sistematiese oorsig is Cochrane metodiek gebruik om die risiko van vooroordeel van ingesluite ewekansige, gekontroleerde studies te evalueer. Assosiasie tussen bron van befondsing en die risiko van vooroordeel, asook kliniese uitkomste en gevolgtrekkings was beoordeel. In die beskrywende studie, is alle genoteerde maatskappye wat babavoeding produkte vervaardig met bygevoegde synbiotika, probiotika of prebiotika vir babas geïdentifiseer en uitgenooi om deel te neem. 'n Uitnodigingsbrief is vir die relevante maatskappye gestuur om hul bereidwilligheid om deel te neem te bevestig. Indien hulle wel bereid was om deel te neem was 'n vraelys met 'n skriftelike toestemming vorm gestuur. Beskrywende statistiek en assosiasies tussen kategoriese veranderlikes was getoets met behulp van 'n Chi-kwadraat toets. Resultate Fase een: Oorsig oor premature babas: 8 studies was ingesluit. Probiotika verhoog stoelgang frekwensie met geen effek op ander kliniese uitkomste. Prebiotika verhoog ook stoelgang frekwensie en slegs bifidobakteriële tellings. Oorsig oor die vol termyn babas: 25 studies was ingesluit. Synbiotika verbeter stoelgang frekwensie, maar het geen effek op ander kliniese uitkomste gehad nie. Probiotika het nie 'n effek op enige kliniese uitkoms gehad nie. Prebiotika verhoog gewigstoename en stoelgang frekwensie met geen effek op ander uitkomste. Fase twee: Sistematiese oorsig: 67 studies was ingesluit, en die meerderheid was befonds deur die voedsel bedryf. Daar was geen beduidende assosiasie tussen die bron van befondsing en vier gebiede (toekenningsvolgorde, toekenningsverberging, studie verblinding, selektiewe verslaggewing), en die meerderheid van gerapporteerde kliniese uitkomste of skrywers se gevolgtrekkings. Die bron van befondsing was beduidend verbind met twee gebiede (onvolledige uitslag data, vry van ander vooroordeel), antibiotika gebruik en gevolgtrekkings op gewigstoename. Beskrywende studie: 25 maatskappye is geïdentifiseer en genooi om deel te neem. Geen maatskappy het ingestem om deel te neem aan die studie om verskillende redes. Gevolgtrekkings Fase een: Oorsig oor premature babas: Daar is nie genoeg bewyse dat die aanvulling met probiotika of prebiotika resultate in verbeterde groei en kliniese uitkomste in uitsluitlik formule gevoede premature babas tot gevolg het nie. Oorsig oor die volle termyn babas: Daar is nie genoeg bewyse om te sê dat die aanvulling van term baba formule met synbiotika, probiotika of prebiotika lei tot verbeterde groei of kliniese uitkomste in termyn babas. Daar is geen inligting beskikbaar om te stel of synbiotika beter is as probiotika of prebiotika nie. Fase twee: Sistematiese oorsig: In studies op babas gevoed met formule melk wat probiotika, prebiotika of synbiotika bevat het, het die bron van befondsing nie meerderheid van die uitkomste in die guns van die borge se produkte beïnvloed nie. Meer nie-industrie befondsde navorsing is nodig om verder die impak van befondsing op kliniese uitkomste en skrywers se gevolgtrekkings te evalueer. Beskrywende studie: Aangesien al die maatskappy deelname geweier het, kon geen gevolgtrekking gemaak word of die voedsel bedryf bewyse oor die gebruik van probiotika, prebiotika of synbiotika toepas nie. Meer deursigtigheid is nodig van die formule vervaardigers oor hoe hulle die bewyse oor die gebruik van probiotika, prebiotika of synbiotika toepas.

Orientador: Prof. Dr. Bruno Lemos Batista / Dissertação (mestrado) - Universidade Federal do ABC. Programa de Pós-Graduação em Ciência e Tecnologia/Química, 2016. / O arroz e seus derivados sao importantes fontes de elementos essenciais e nao essenciais. Os elementos essenciais como ferro e selenio sao vitais para manter varios processos bioquimicos. Por outro lado, elementos nao essenciais, como por exemplo, o arsenio (As), podem estar presentes em alimentos a base de arroz e, consequentemente, expor a populacao. A exposicao de populacoes mesmo a baixas concentracoes de As pode levar a graves consequencias para saude humana, especialmente criancas e celiacos que consomem alimentos a base de arroz. O objetivo desse estudo foi determinar a concentracao de As em produtos a base de arroz (macarrao, doces, biscoitos, barra de cereal, farinha, pao, leite e mingau) e papinhas infantis, bem como estimar a ingestao diaria de As e avaliacao in vitro da bioacessibilidade atraves do consumo destes alimentos no Brasil. As determinacoes totais e bioacessiveis para As foram realizadas usando ICP-MS. Para o estudo de especiacao, a tecnica utilizada foi HPLC-ICP-MS. As concentracoes de As nos alimentos a base de arroz variaram entre 15,8 e 101,3 ¿Êg kg-1. Ja nas papinhas infantis contendo arroz, os valores ficaram entre 4,2 e 16,0 ¿Êg kg-1. Considerando os dados da especiacao quimica, amostras de macarrao, farinha e mingau apresentaram a seguinte concentracao de As inorganico (As-i): 79,7; 63,4 e 34,3 ¿Êg kg-1, respectivamente que representa 39,4; 56,8 e 33,5 % da concentracao total de As. Ja as papinhas infantis as concentracoes de As-i foram de 17,5 e 22,8 ¿Êg kg-1. A especiacao revelou que As-i, forma mais toxica, esta presente em 100% das amostras analisadas. Praticamente todas as amostras apresentarem uma fracao bioacessivel maior que 50 %. O que demonstra o potencial bioacessivel do As em amostras a base de arroz incluindo alimentos infantis. O Brasil segue padroes e normas internacionais desenvolvidos pelo Codex Alimentarius para contaminantes em alimentos como o As em arroz. Parametros de seguranca alimentar, bem como regulamentos e codigo de praticas para a agricultura e processamento de alimentos, devem ser adotadas no futuro visando a melhoria de avaliacao de risco. / Due to intense anthropogenic activities, metal ions are among the most important Rice and its derivatives are important sources of essential and non-essential. The essential elements such as iron and selenium are vital to maintain multiple biochemical processes. On the other hand, non-essential elements, such as arsenic (As), may be present in rice-based food and thus exposing the population. The exposure of populations even at low concentrations of As can lead to serious consequences for human health, especially children and celiacs consuming rice-based foods. The aim of this study was to determine the concentration of As in rice products (pasta, pastries, biscuits, cereal bar, flour, bread, milk and porridge) and children's baby food, and to estimate the daily intake of As and in vitro evaluation the bioaccessibility through the consumption of these foods in Brazil. Total determinations and bioaccessible for were performed using ICP-MS. For the study of speciation, the technique used was HPLC-ICP-MS. The concentrations in rice-based foods ranged between 15.8 and 101.3 ìg kg-1. Already infant baby food concentrations of As-i were 17.5 and 22.8 ìg kg-1. Speciation showed that As-i, the most toxic form, is present in 100% of the samples. Virtually all samples present a bioaccessible fraction greater than 50%. This demonstrates the potential of bioaccessible As in rice-based samples including baby food. Brazil follows international standards and norms developed by the Codex Alimentarius for contaminants in foods such as As in rice. Food safety parameters and regulations and code of practice for agriculture and food processing, should be adopted in the future in order to improve risk assessment.

Orientador: Adriana Zerlotti Mercadante / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-10T19:18:08Z (GMT). No. of bitstreams: 1 Cury_RenataDelBel_M.pdf: 406098 bytes, checksum: 03090f5878c4c5284bd0fd52c8de4c80 (MD5) Previous issue date: 2008 / Resumo: Cada vez mais se associa o consumo de frutas e vegetais à prevenção do câncer, doenças cardiovasculares, osteoporose e diabetes por serem excelentes fontes de compostos fitoquímicos com ação antioxidante que evitam o estresse oxidativo e seus efeitos. Os carotenóides, compostos fenólicos (inclui flavonóides e antocianinas) e ácido ascórbico são os compostos antioxidantes mais abundantes em frutas e vegetais. Entretanto, na primeira infância o consumo de frutas e vegetais in natura tem sido substituído por alimentos industrializados na forma de alimentos infantis (¿baby-food¿). Como o teor destes compostos antioxidantes presentes em produtos infantis a base de frutas e vegetais comercializados no Brasil ainda não foram determinados, o escopo deste trabalho foi analisar os teores de carotenóides, fenóis, flavonóides e ácido ascórbico e com o uso dos métodos ABTS e DPPH foi medido a atividade anti radical livre destes produtos. Além disso, foi avaliado o efeito do aquecimento em microondas sobre os teores dos compostos antioxidantes. Foram analisadas papinhas de ameixa, goiaba, maçã, pêra, banana e sopinhas de cenoura e mandioquinha adquiridas no comercio da cidade de Campinas, estado de São Paulo. A maior concentração de carotenóides totais foi observada na papinha de cenoura (6,4 mg/100g). A papinha de ameixa foi a que mostrou o maior teor de fenóis totais (49,3 mg/100g) e de flavonóides totais (38,5 mg/100g) sendo que também apresentou a melhor desativação do radical ABTS. Devido à sua adição nos produtos de frutas, foram encontrados altos valores de ácido ascórbico de 262 mg/100g para goiaba, 350 mg/100g para pêra, 475 mg/100g para banana, 150 mg/100 para ameixa e 122 mg/100g para maçã. Não foi detectado flavonóides totais nas sopinhas de legumes e nem antocianinas totais nas papinhas de goiaba e ameixa. Não houve perda significativa de carotenóides totais, fenóis totais e ácido ascórbico após aquecimento em microndas das sopinhas de legumes. Houve melhor correlação entre o teor de fenóis totais (r=0,93) e a atividade anti radical livre ABTS do que com o teor de flavonóides totais (r=0,86). Houve ainda correlação negativa em relação aos teores de carotenóides totais (r= -0,0854) e ácido ascórbico (r= -0,7049) e a atividade anti radical livre (ABTS). Foi observada baixa correlação (r=0,78) entre os métodos anti radical livre ABTS e DPPH / Abstract: The association between a diet rich in fruits and vegetables and decreased risk of cancer, cardiovascular disease, osteoporosis and diabets is supported because these foods are excelent sources of bioactive compounds with antioxidant activity that can act or prevent the effects of oxidative stress. Carotenoids, phenolic compounds (including flavonoids and anthocyanins) and ascorbic acid, are the most abundant antioxidant compounds in fruits and vegetables. However, the consumption of fruits and vegetables in the first childhood has been substituted by commercial baby foods. Since the levels of these antioxidant compounds found in baby foods commercialized in Brazil were not previously determined, the aim of this study was to quantify the contents of carotenoids, phenolic compounds, flavonoids and ascorbic acid, as well as to evaluate the antioxidant activity by two methods (ABTS and DPPH·) on some Brazilian baby foods. In addition, the effect of microwave heating on these antioxidant compounds was determined. The following baby products were analyzed: guava, dried plum, apple, pear and banana, ) and the vegetables ones (carrot and ¿mandioquinha¿). The highest concentration of total carotenoid was found in carrot baby food (6.4 mg/100g). Dried plum product had the highest contents of total phenols (49.3 mg GAE/100g) and total flavonoids (38,5 mg CE/100g) and also was the best free radical scavenger product assessed by the ABTS method. Since ascorbic acid is added to the based fruits baby foods, its contents were higher in all of them, such as 262 mg/100g in guava, 350 mg/100g in pear, 475 mg/100g in banana, 150 mg/100 in plum and 122 mg/100g in apple. .The vegetable baby s foods did not present flavonoids and anthocyanins were not detected in guava and dried plum baby foods. The losses of total carotenoids, total phenols and ascorbic acid were not statistically significant after microwave heating of vegetable baby foods. The highest correlation was observed between the total phenolic contents (r=0.93) ABTS·+ scavenger, followed by total flavonoids (r=0,86). However, negative correlations between the ABTS method and total carotenoids (r= -0,0854) and total phenols (r= -0,7049) were obtained. There was weak correlation (r=0.73) between the two free radical scavenger methods DPPH and ABTS / Mestrado / Mestre em Ciência de Alimentos

Orientador: Marcelo Cristianini / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-03T21:15:51Z (GMT). No. of bitstreams: 1 Pinho_ClaudiaReginaGoncalves_M.pdf: 501738 bytes, checksum: 4538e004b367eac7c4ade13765125d3e (MD5) Previous issue date: 2003 / Resumo: Neste trabalho foi elaborado um modelo matemático do processo de transferência de calor durante a esterilização de um alimento condutivo infantil embalado em recipiente de vidro. O modelo tridimensional construído utilizando-se a técnica de elementos finitos para a resolução das equações diferenciais de transferência de calor considerou as propriedades térmicas do alimento, do vidro, do head space e da tampa metálica separadamente e a temperatura inicial da amostra e o perfil real de temperatura da autoclave utilizada para o processo de esterilização foram as condições de contorno aplicadas. As propriedades térmicas do alimento, condutividade térmica, calor específico, densidade e difusividade térmica, foram determinadas experimentalmente. Os valores obtidos foram: 0,59 W/mºC, 3776 J/kgºC, 1024 kg/m3 e 1,54 x 10-7 m2/s, respectivamente. O valor do coeficiente convectivo de transferência de calor (h) foi calculado a partir de perfis tempo x Temperatura obtidos experimentalmente. O processamento térmico foi dividido em quatro partes: come up, aquecimento, início de resfriamento (10 primeiros minutos de resfriamento) e final de resfriamento, sendo calculado um valor de h para cada trecho. Uma vez calculados os valores de h, o modelo de distribuição de temperatura no interior da embalagem foi validado experimentalmente através da realização de ensaios a 121°C. Ao se realizar uma regressão linear entre os valores de temperatura fornecidos pelo modelo e aqueles obtidos experimentalmente os parâmetros estatísticos obtidos foram R2 = 0,9925 e Inclinação = 1,0053, indicando que o mesmo foi capaz de prever de maneira satisfatória a distribuição de temperaturas no interior da amostra durante o processamento. Foram determinados os parâmetros Dez do Bacillus stearothermophilus em alimento infantil. Os resultados obtidos para o parâmetro D a 110, 115 e 121°C foram 32,67,9,31 e 1,57 minutos, respectivamente. O valor de z encontrado foi de 8,32°C. A partir da distribuição de temperaturas no interior da embalagem fornecida pelo modelo, foi estimada a destruição térmica de microrganismos e de nutrientes do processo. O cálculo da destruição térmica de microrganismos foi feito através da determinação da Esterilização Média da Massa. Foram realizados ensaios de validação do modelo de destruição microbiológica submetendo-se amostras inoculadas com Bacillus stearothermophilus a processamentos subletais a 110 e 115°C. O número de reduções decimais obtido em cada um dos processos foi confrontado com a destruição prevista pelo modelo, sendo que o modelo considerou os valores de O e z determinados experimentalmente. Nos processos a 115°C o desvio entre valores previstos e valores obtidos experimentalmente foi sempre inferior a 27% e naqueles realizados a 110°C este desvio foi sempre inferior a 12%. Foram realizadas ainda simulações de processos a 115 e 121°C variando-se a taxa de aquecimento da autoclave de 5 a 20°C/min e também de processos onde parte do valor de Fp foi obtida a 115 e parte a 121°C. Nestes processos o critério de parada foi o valor de Fp equivalente a uma redução de 6 ciclos do Bacillus stearothermophilus ter sido atingido. Verificou-se que quanto maior a porcentagem de Fp obtida a 121°C maior é a retenção de tiamina. Nas simulações de processos realizadas a 121°C a retenção média de tiamina foi de 48,71 % e naquelas realizadas a 115°C esta retenção foi de 55,90%. Não foram observadas diferenças significativas na retenção de tiamina entre processos realizados a uma mesma temperatura porém com diferentes taxas de aquecimento da autoclave / Abstract: The aim of this work was to build a mathematical model of the heat transfer during the sterilization process of a conductive baby food packed in glass container. The 3-dimensional model was built using the finite element technique. The model considered the thermal properties of food, glass, headspace and metal cap individually. The sample initial temperature and the retort real temperature profile were the boundary conditions applied. Thermal properties of food, thermal conductivity, specific heat, density and thermal diffusivity, were experimentally determined. The obtained values were: 0.59 W/mºC, 3776 J/kgºC, 1024 kg/m3 e 1.54 x 10-7 m2/s, respectively. The value of the heat transfer coefficient (h) was calculated from time-Temperature profiles obtained experimentally. The thermal process was divided into 4 parts: come up, heating, early cooling (10 first minutes) and final cooling and different values of h were calculated for each part. The heat transfer model of the sterilization process was experimentally validated through processes carried out in water at 121°C. The linear regression between temperature profiles generated by the model and the ones experimentally obtained showed that they were in good agreement (R2=0.9925 and slope=1.0053), showing that the model was able to predict satisfactorily temperature distribution into the sample during sterilization process. Thermal death parameters, O and z, of Bacillus stearpthermophilus in baby food were determined. The results obtained for O value were 32.67,9.31 and 1.57 minutes at 110, 115 and 121°C, respectively. The z value obtained was 8.32°C. The mass average value was estimated and experimental processes were carried out at 110 and 115°C in order to validate the microbiological destruction mode!. At these processes, inoculated samples of baby food were submitted to sub lethal processes and the experimental microbiological destruction was determined and compared with the values estimated by the mode!. The results showed that for processes at 110°C the differences between experimental and predicted results were less than 12% and for those processes at 115°C this differences were less than 27%. Finally, two types of simulations set to achieve a Fp value of 9.42 minutes were done. The first group considering different retort heating rates (5 to 20°C/min) at 115 and 121°C and the latter obtaining part of Fp value at 115°C and part at 121°C. The thiamine retention of each process was estimated and the results showed that the higher Fp percentage is obtained at 121°C, the better the process is. No significant differences were observed in thiamine retention in equivalent process considering different retort heating rates at the same temperature / Mestrado / Mestre em Tecnologia de Alimentos

Thesis (MSc)--University of Stellenbosch, 2007. / ENGLISH ABSTRACT: The World Health Organisation (WHO) estimates that at least 75% of infants receive infant formula milk (IFM) either entirely or in conjunction with breast milk during the first four months after birth. The presence of the emerging pathogen Enterobacter sakazakii in IFM has been associated with rare but fatal cases of neonatal infections and deaths. There is thus a need for accurate methods for the rapid detection of E. sakazakii in foods. At present, the methods used to detect and identify this micro-organism are inadequate, controversial and contradictory. The aim of this study was to determine the most suitable method for E. sakazakii detection after evaluation of the currently available methods. A further aim was to optimise a polymerase chain reaction (PCR) method for the detection of only viable E. sakazakii cells utilising the DNA-intercalating dyes ethidium monoazide (EMA) and propidium monoazide (PMA). The Food and Drug Administration (FDA) method for E. sakazakii detection was utilised to select 50 isolates from IFM and 14 from the environment, regardless of colony appearance. These isolates were identified by sequencing a 1.5 kilobase (kb) fragment of the 16S ribosomal DNA (rDNA) and by using the National Centre for Biotechnological Information (NCBI) database to confirm the closet known relatives. Seven of the 50 (14%) IFM isolates and six of the 14 (43%) environmental isolates were identified as E. sakazakii. The methods that were evaluated for accuracy in detecting and identifying these E. sakazakii isolates included yellow pigment production on tryptone soy agar (TSA), chromogenic Druggan-Forsythe-Iversen (DFI) and Enterobacter sakazakii (ES) agars and PCR using six different species-specific primer pairs described in the literature. The suitability of the FDA method was lowered by the low sensitivity, specificity and accuracy (87%, 71% and 74%, respectively) of using yellow pigment production for E. sakazakii identification. DFI and ES agars were shown to be sensitive, specific and accurate (100%, 98% and 98%, respectively) for the detection of E. sakazakii. The specificity of the PCR amplifications was found to vary between 8% and 92%, with Esakf and Esakr being the most accurate of the primer pairs evaluated. The current FDA method for E. sakazakii detection requires revision in the light of the availability of more sensitive, specific and accurate detection methods. Based on the results obtained in this study, a new method is proposed for the detection of E. sakazakii in food and environmental samples. This proposed method replaces the culturing steps on violet red bile glucose agar (VRBGA) and TSA with culturing on chromogenic DFI or ES agar. For identification and confirmation of presumptive E. sakazakii isolates, the oxidase test, yellow pigment production and API biochemical profiling is replaced by DNA sequencing and/or species-specific PCR with the most accurate primer pair (Esakf and Esakr). The amendments to the current FDA method will reduce the time to detect E. sakazakii from approximately 7 days to 4 days and should prove to be more sensitive, specific and accurate for E. sakazakii detection. In this study, a novel PCR-based method was developed which was shown to be capable of discriminating between viable and dead E. sakazakii cells. This was achieved utilising the irreversible binding of bacterial DNA to photo-activated PMA or EMA in order to prevent PCR amplification from the dead cells. At concentrations of 50 and 100 μg.ml-1, PMA completely inhibited PCR amplification from dead cells, while causing no significant inhibition of the PCR amplification from viable cells. EMA was equally effective in preventing PCR amplification from dead cells, however, it also inhibited PCR amplification from viable cells. PMA-PCR in particular, will be useful for assessing the efficacy of processing techniques, as well as for monitoring the resistance, survival strategies and stress responses of E. sakazakii. This will be an important step in the efforts to eliminate E. sakazakii from food and food production environments. / AFRIKAANSE OPSOMMING: Die Wêreld Gesondheidsorganisasie (WGO) beraam dat ten minste 75% van alle babas net baba formule melk (BFM) of BFM in kombinasie met moedersmelk in die eerste vier maande na geboorte kry. Die teenwoordigheid van die voortkomende patogeen Enterobacter sakazakii in BFM is al geassosieer met skaars maar noodlottige gevalle van neonatale infeksies en sterftes. Akkurate metodes word dus benodig vir die vinnige deteksie van E. sakazakii in voedsel. Die metodes wat huidiglik gebruik word vir die deteksie en identifikasie van hierdie mikroörganisme is onvoldoende, kontroversieël en teenstrydig. Die doel van hierdie studie was om die beste metode vir die deteksie van E. sakazakii te bepaal, na 'n evaluasie van die metodes wat huidiglik beskikbaar is. 'n Verdere doel was om 'n polimerase ketting reaksie (PKR) metode vir die deteksie van slegs lewensvatbare E. sakazakii selle te optimiseer deur gebruik te maak van die DNSbindende kleurstowwe, etidium mono-asied (EMA) en propidium mono-asied (PMA). Die Voedsel en Medisyne Administrasie (VMA) se metode vir E. sakazakii deteksie is gebruik om, ongeag van die kolonie kleur, 50 isolate vanuit BFM en 14 isolate vanuit die omgewing te kies. Hierdie isolate is geïdentifiseer deur die DNS volgorde van 'n 1.5 kilo-basis (kb) fragment van die 16S ribosomale DNS (rDNS) te bepaal en die Nationale Sentrum vir Biotegnologiese Informasie (NSBI) databasis te gebruik om die mees verwante spesie te bevestig. Sewe van die 50 (14%) BFM isolate en ses van die 14 (43%) omgewings isolate is geïdentifiseer as E. sakazakii. Die metodes wat geëvalueer is in terme van akkuraatheid vir deteksie en identifikasie van hierdie E. sakazakii isolate het PKR met ses verskillende spesie-spesifieke peiler pare soos beskryf in die literatuur, geel-pigment produksie op triptoon soja agar (TSA) en chromogeniese Druggan-Forsythe-Iversen (DFI) en Enterobacter sakazakii (ES) agars ingesluit. Die geskiktheid van die VMA metode is verlaag deur die lae sensitiwiteit, spesifisiteit en akkuraatheid (87%, 71% en 74% onderskeidelik) van geel pigment produksie vir E. sakazakii identifikasie. Chromogeniese DFI en ES agars was sensitief, spesifiek en akkuraat (100%, 98% en 98% onderskeidelik) vir die identifikasie van E. sakazakii. Die spesifisiteit van die PKR produkte het gewissel tussen 8% en 92%, en Esakf en Esakr is as die akkuraatste geëvalueerde peiler paar geidentifiseer. Die huidige VMA metode vir E. sakazakii deteksie vereis hersiening aangesien meer sensitiewe, spesifieke en akkurate deteksiemetodes voortdurend beskikbaar word. 'n Nuwe metode, gebaseer op die resultate van hierdie studie, word voorgestel vir die deteksie van E. sakazakii in voedsel- en omgewingsmonsters. Die voorgestelde metode vervang die kwekingsstap op violet rooi gal glukose agar (VRGGA) en TSA deur kweking op chromogeniese DFI of ES agars. Verder word die oksidase toets, geel pigment produksie en API biochemiese profiele van vermoeidelike E. sakazakii isolate vervang deur DNS volgorde bepaling en/of spesie-spesifieke PKR met die mees spesifieke peiler paar (Esakf and Esakf) vir die identifikasie en bevestiging van E. sakazakii. Die voorgestelde wysigings van die VMA metode sal die tydsduur van E. sakazakii identifikasie van 7 dae na 4 dae verminder, en behoort ook meer sensitief, spesifiek en akkuraat te wees vir die deteksie van E. sakazakii. 'n Nuwe PKR-gebaseerde metode wat tussen lewensvatbare en dooie E. sakazakii selle kan onderskei is in hierdie studie ontwikkel. Dit is bereik deur die onomkeerbare binding van bakteriële DNS aan lig-geaktiveerde EMA of PMA om die PKR amplifisering van dooie selle te voorkom. Konsentrasies van 50 en 100 μg.ml-1 PMA het PKR amplifikasie heeltemal geïnhibeer, terwyl geen inhibisie van lewensvatbare selle bespeur kon word nie. EMA was ook suksesvol in die voorkoming van die PKR amplifikasie van dooie selle, alhoewel daar ook 'n mate van DNS inhibisie was tydens die amplifikasie van lewensvatbare selle. PMA-PKR kan ook van nut wees vir die assessering van die doeltreffendheid van prosesseringstegnieke, en ook vir die waarneming van die weerstandigheid, oorlewingsstrategieë en stresresponse van E. sakazakii. Dit sal 'n belangrike stap wees in pogings om E. sakazakii van voedsel en voedsel produksieomgewings te elimineer.

No description available.

Abstract: Introduction: Exclusive breastfeeding for the first six months of an infant's life is recommended worldwide. In 1998 the South African Demographic and Health Survey (SADHS) showed that only 10% of mothers exclusively breastfeed at three months. As the HIV virus is transmissible via breast milk, UNAIDS (2002) recommends that women in developing countries should be given a choice of feeding method after being counselled on the risks and benefits of breast feeding versus formula feeding. As a result, the Prevention of Mother-to-Child Transmission (PMTCT) programme was launched in KwaZulu-Natal with the aim of providing interventions to prevent Mother-to-Child Transmission of the HIV virus. However, research has shown that infant feeding practices are influenced by numerous factors. Ultimately mothers will feed their infants in a manner they feel comfortable with, even if it is not always the most appropriate choice. Aim: The aim of this study was to determine and compare current infant feeding practices and some of the factors that influenced these practices among Zulu mothers with 0 - 6 month old infants attending PMTCT and non-PMTCT clinics in Central Durban, KwaZulu-Natal. Methodology: A cross-sectional, descriptive survey was conducted amongst 150 mothers sampled from three non-PMTCT clinics and 150 mothers sampled from three PMTCT clinics. Systematic random sampling of mothers attending the two types of clinics was used to ensure an equal number of mothers· with infants aged 0 - < 6 weeks, 6 - < 14 weeks and 14 weeks to 6 months. The number of mothers interviewed per clinic was determined proportionate to clinic size. Interviews were conducted in Zulu by trained fieldworkers according to a structured interview schedule consisting of 87 open- and closed-ended questions. Summary of most important findings and conclusion: Overall, one quarter of the mothers attending non-PMTCT and one third of mothers at PMTCT clinics were practising exclusive breastfeeding at the time of the survey. The general trend was that mothers attending PMTCT clinics were more inclined than those attending non-PMTCT clinics to breastfeed their infants exclusively (34% versus 24% respectively) or to formula feed (16,7% versus 12,7% respectively). Furthermore, there was a significant decline in exclusive breastfeeding and predominant breastfeeding with increasing infant age in both clinic groups. The opposite held true for mixed feeding and formula feeding in that infants were more inclined to mixed feeding or formula feeding with increasing infant age. In both clinic groups, exclusive breastfeeding was the method of choice in the 0 - < 6 week age category, while a preference for mixed feeding was shown in the 6 - < 14 week category. This trend persisted in the 14 week - < 6 month age category, especially in the non-PMTCT clinics, while there was a small but pronounced increase in formula feeding amongst PMTCT mothers. Although these findings can be explained as a result of implementing the PMTCT programme, the positive trends observed in non-PMTCT clinics serve as an indicator that the Integrated Nutrition Programme (INP) and Baby Friendly Hospital initiative have also had an impact on the feeding choices mothers make. Despite the limited duration of the PMTCT programme at the time of the study, indicators of the impact of the intervention include that a lower percentage of PMTCT mothers introduced foods and/or liquids in addition to breast milk to their infants before six months of age compared to non-PMTCT mothers. Furthermore, more mothers attending PMTCT clinics were shown how to breastfeed and were more likely to have received information about formula feeding. Despite these indicators of a positive impact of the PMTCT programme, the mean age for introducing liquids and/or solids in addition to breast milk was about six weeks and the incidence of this practice was very high for both groups. The similar incidence of formula feeding observed between the two clinic groups suggests the presence of constraints to safe infant feeding choices among mothers attending PMTCT clinics. As observed, infant feeding practices were still not ideal in either of the two clinic groups. However, the high level of antenatal clinic attendance documented for both groups serves as evidence that, if opportunities for providing mothers with appropriate infant feeding advice are utilized optimally, the antenatal clinic could serve as an ideal medium through which infant feeding education can take place, especially as the clinic-based nursing staff were cited as the most important source of infant feeding information by both groups of mothers in the antenatal and postnatal phases. The documented infant feeding practices should be interpreted against the backdrop of factors such as socio-demographic characteristics of the mothers, availability of resources such as social support from peers and significant others and reigning infant feeding beliefs that could influence infant feeding decisions. Predictors of exclusive breastfeeding in PMTCT and non-PMTCT clinics were determined by means of multivariate logistic regression analysis. Significant values were obtained for both clinic groups in terms of the infant not having received liquids in addition to breast milk. No additional predictors were found amongst mothers attending non-PMTCT clinics, however predictors amongst mothers attending PMTCT clinics included whether the mother had not visited the clinic since the infant's birth, whether she practiced demand feeding and whether she was experiencing stress at the time of the study. The limited number of predictors of exclusive breastfeeding documented in this study, especially among non-PMTCT mothers may be explained by the fact that infant feeding behaviour is multifactorial by nature and the interaction between factors that influence feeding choice is strong. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2005.

Department of Nutrition / MSCPNT