: Les grains de kéfir sont des ferments lactiques constitués d'une microflore complexe et diversifiée. Celle d'un grain de kéfir (KJ) a été caractérisée par une approche méthodologique classique d'isolements microbiens sur des milieux de culture sélectifs et, pour les bactéries lactiques, par une approche indépendante d'isolements bactériens par culture. Cette dernière consistait en l'analyse de la séquence des régions V1 et V2 de l'ADNr 16S, amplifiées à partir de l'ADN extrait du grain. La sensibilité de la méthode a été augmentée à cette occasion en dissociant les amplifications géniques des populations lactiques minoritaires et majoritaires du grain. La flore identifiée dans le grain KJ comprenait Acetobacter sp., Kazachstania exigua, Lactobacillus kefiranofaciens subsp. kefirgranum, Lb. kefiri, Lb. parakefiri, Lactococcus lactis subsp. lactis et Leuconostoc mesenteroides, et était dépourvue de microcoques, de pédiocoques, de Weissella viridescens, de bactéries indicatrices de défauts d'hygiène, de Salmonella sp. et de Listeria monocytogenes. Dans le but de vérifier le caractère complet des espèces mises à jour, une reconstitution du grain à partir des micro-organismes qui en ont été isolés a été envisagée. Des conditions expérimentales favorables à la formation de grains dans un substrat lacté ont été recherchées à partir d'extraits du grain KJ renfermant un consortium microbien a priori complet. Ces essais de reconstitution n'ont pas conduit à la formation de grains de kéfir mais l'un d'eux a conduit à la formation de biofilms. Cet évènement a été reproduit dans du lait de façon répétable avec des consortiums reconstitués à partir des micro-organismes individuels isolés du grain KJ.

This project was initiated in an attempt to determine the effects of fermented dairy products on plasma cholesterol concentrations. The literature indicates that bacteria, in the small intestine, could modify circulating cholesterol levels through their effects on bile acid excretion. As a result, cholesterol is mobilized for de novo bile synthesis. Furthermore, bacterial fermentation in the small intestine produces short chain fatty acids which affect cholesterol production by the liver. A cross-over, placebo-controlled study was thus conducted on 13 hypercholesterolemic men to establish the effect of kefir, a fermented milk, on cholesterol levels. Subjects consumed kefir or milk for periods of four weeks separated by a four-week washout period. There was no effect on plasma total cholesterol, high-density lipoprotein cholesterol, or triacylglyceride levels upon treatment with kefir. Milk significantly decreased myristic acid (p < 0.01) and palmitoleic acid (p < 0.05) concentrations. Fractional synthesis rate of cholesterol was significantly greater after kefir supplementation than after milk supplementation (0.057 vs 0.042g/day). The effect seen on fractional synthesis rate of cholesterol may be the result of a significant decrease in low-density lipoprotein cholesterol concentration (p < 0.05) during milk supplementation. However, it was concluded that the bacterial content of kefir may have been too low to produce any significant effect on blood lipid parameters.

No description available.

Thesis (MSc)--University of Stellenbosch, 2001. / ENGLISH ABSTRACT: Kepi is an acidic, self-carbonated milk beverage that is produced by fermenting milk with grain-like structures that contain naturally occurring microbes, including lactic acid bacteria (LAB) and yeasts. The specific microbes present in the Kepi grains are responsible for an acidic-alcoholic fermentation of the milk and also contributes to the various health properties exhibited by Kepi. The combination of microbes in the Kepi grains can vary considerably depending on which type of milk is fermented, the method by which Kepi is produced, the origin of the grains and how the grains are stored. In this study, the impact of various environmental conditions including the different stages during Kepi production, grain origin, Iyophilisation and packaging in three different packaging materials, on the microbial community of Kepi grains were studied using selective growth media, morphology and biochemical characteristics. It was found that there was a general decrease in the microbial counts from laboratory produced Kepi grains, the longer Kepi was produced on a continuous basis. This decrease in microbial counts was also observed during the different stages of Kepi production. The average LAB counts obtained from laboratory produced grains decreased from 1.1 x 108 cfu.q" after 3 d of activation to 6.3 x 107 cfu.q' after 10 d of mass production to 9.7 x 106 cfu.q' after a further 30 d of normal Kepi production. The average yeast counts increased from no detectable yeasts after 3 d of activation to 5.7 x 107 cfu.q' after 10 d of mass production and then decreased again to 7.2 x 106 cfu.q' after 30 d of normal Kepi production. The combination of the isolates varied according to the method by which the Kepi grains were produced and the stress conditions that were applied. Laboratory produced Kepi grains contained the following LAB: Lactobacillus fermentum, Lb. brevis 3, Lb. p/antarum, Lb. de/brueckii subsp. de/brueckii, Lactococcus /actis subsp. /actis and Leuconostoc mesenteroides subsp. cremoris. The identified yeasts and mycelial fungi were a Zygosaccharomyces strain, Cryptococcus humico/us, Candida /ambica, C. krusei, C. kefyr and Geotrichum candidum. The influence of grain origin on the microbial content of Kepi grains was also investigated using samples of Kepi grains from eight different Southern African sources. The microbial counts of the various Kepi grain samples were found to vary from 6.0 x 105 cfu.q" to 1.7 x 108 cfu.q". Five Lactobacillus, two Leuconostoc, four Candida, one Saccharomyces and a Zygosaccharomyces strain were isolated from these grains, with each grain type having its own unique microbial combination. The microbial content of the Kepi grains that were Iyophilised, packaged in three different packaging materials and stored at room temperature for two months, was very similar. Lactobacillus delbrueckii subsp. delbrueckii was isolated from the Kepi grains packaged in "low density polyethylene film" (LOPE). The grains packaged in "oriented polyester film" (OPET) contained Lb. delbrueckii subsp. delbrueckii and Lb. brevis, while Lb. delbrueckii subsp. delbrueckii and Lb. curvatus was present in the grains packaged in "methallised oriented polyester film" (MOPET). The average microbial counts obtained from the Kepi grains packaged in OPET (2.7 x 106 cfu.q') were only slightly higher than that of the grains packaged in LOPE (1.2 x 106 cfu.q') and OPET (1.4 x 106 cfu.q'). It was concluded that packaging materials for Kepi grains should rather be evaluated on the quality of Kepi produced with the packaged grains than by the specific characteristics of the packaging materials. The enrichment of Kepi grains with propionibacteria was also evaluated. A polymerase chain reaction (PCR) based method, specifically designed for the rapid identification of propionibacteria, was developed and tested successfully. Using this technique it was concluded that propionibacteria were not a natural part of the Kepi beverage and grains as used in this study. However, during the enrichment of the grains with propionibacteria it was determined that a propionibacteria concentration of 1 x 108 cfu.rnt' was needed for successful PCR amplification results. The data obtained in this study clearly showed that the method by which Kepi is produced, the origin of Kepi grains and the method of Kepi grain preservation changes the relationship between the microbes constituting the grains to such an extent that a different microbial community is assembled. It was also concluded that traditional methods should be used together with newer methods in determining this microbial community. / AFRIKAANSE OPSOMMING: Kepi is 'n self-gekarboneerde, effens suur melkdrankie wat geproduseer word deur melk te fermenteer met korrels waarin mikrobes (melksuurbakterieë en giste) natuurlik voorkom. Die mikrobes in die Kepi korrels is verantwoordelik vir 'n suuralkoholiese fermentasie en dra verder by tot die verskeie gesondheidseienskappe wat Kepi besit. Die kombinasie van mikrobes in die Kepi korrels wissel afhangende van die tipe melk wat gebruik word, die metode waarvolgens Kepi gemaak word, die oorsprong van die korrels en hoe die korrels geberg word. In hierdie studie is die impak van verskeie omgewingskondisies insluitende die verskillende stadiums tydens Kepi produksie, korreloorsprong, vriesdroging en verpakking in drie verskillende verpakkingsmateriale, op die mikrobiese samestelling van Kepi korrels bepaal m.b.v. selektiewe groei media en morfologiese en biochemiese eienskappe. Dit is gevind dat daar 'n afname was in die mikrobiese tellings van laboratorium geproduseerde Kepi korrels hoe langer Kepi op 'n aaneenlopende basis geproduseer is. Die afname in mikrobiese tellings is ook waargeneem tydens die verskillende stadiums van Kepi produksie. Die gemiddelde melksuurbakterieë tellings van laboratorium geproduseerde korrels het afgeneem vanaf 1.1 x 108 kve.q' na 3 d van aktivering tot 6.3 x 107 kve.q" na 10 d van massakweking tot 9.7 x 106 kve.q" na 'n verdere 30 d van normale Kepi produksie. Die gemiddelde gis tellings het gestyg vanaf geen giste na 3 d van aktivering tot 5.7 x 107 kve.q" na 10 d van massakweking en het toe weer gedaal tot 7.2 x 106 kve.q' na 30 d van normale Kepi produksie. Die kombinasie van die isolate het gewissel na gelang van die metode waarop die Kepi korrels geproduseer is en die stres kondisies wat toegepas is. Laboratorium geproduseerde Kepi korrels het bestaan uit Lactobacillus fermentum, Lb. brevis 3, Lb. p/antarum, Lb. de/brueckii subsp. de/brueckii, Lactococcus /actis subsp. /actis 1en Leuconostoc mesenteroides subsp. cremoris. Die giste en misiliëre fungi wat geïs~leer is was 'n Zygosaccharomyces stam, Cryptococcus humico/us, Candida lambica, C. krusei, C. kefyr en Geotrichum candidum. Die invloed wat die oorsprong van Kepi korrels op die mikrobiese samestelling daarvan het, is bepaal m.b.v. Kepi korrels afkomstig van agt verskillende dele in Suidelike Afrika. Die mikrobiese tellings van die verskeie tipes Kepi korrels het gewissel vanaf 6.0 x 105 kve.q' tot 1.7 x 108 kve.q", Vyf Lactobacillus, twee Leuconostoc, vier Candida, een Saccharomyces en 'n Zygosaccharomyces is geïsoleer vanuit die korrels, waarvan elke tipe korrel sy eie unieke mikrobiese samestelling gehad het. Die mikrobiese samestelling van korrels wat gevriesdroog, verpak is in drie verskillende verpakkingsmateriale en by kamertemperatuur gestoor is vir twee maande, was baie eenders. Vanuit die Kepi korrels wat verpak is in "lae digtheid polietileen film" (LOPE) is Lb. delbrueckii subsp. teetis geïsoleer. Die korrels wat verpak is in "georienteerde poltester film" (OPET) het Lb. delbrueckii subsp. leetis en Lb. brevis besit, terwyl Lb. delbrueckii subsp. leetis en Lb. curvatus teenwoordig was in die korrels wat in "gemetileerde georienteerde poltester film" (MOPET) verpak is. Die gemiddelde mikrobiese tellings van die korrels wat verpak is in OPET (2.6 x 106 kve.q') was effens hoër as dié van die korrels wat verpak is in LOPE (1.2 x 106 kve.q") en MOPET (1.3 x 106 kve.q"). Dit is bepaal dat verpakkingsmateriale vir Kepi korrels eerder geevalueer moet word op die kwaliteit van die Kepi wat met die verpakte korrels geproduseer word, as op die spesifieke eienskappe van die verpakkingsmateriale. Die mikrobiese verryking van Kepi korrels met propionibakterieë is ook ondersoek. 'n Polimerase ketting reaksie (PKR) gebaseerde metode, spesifiek ontwerp vir die vinnige identifikasie van propionibakterieë, is ontwikkel en suksesvol getoets. Met hierdie tegniek is bepaal dat propionibakterieë nie 'n natuurlike deel is van die Kepi drankie en korrels soos gebruik in hierdie studie. Gedurende die verryking van Kepi korrels met propionibakterieë is dit egter ook bepaal dat 'n propionibakterieë konsentrasie van 1 x 108 kve.rnl' nodig is vir suksesvolle PKR amplifikasie resultate. Die data verkry in hierdie studie het duidelik gewys dat die metode van Kepi produksie, die oorsprong van Kepi korrels en die metode waarop Kepi korrels gepreserveer word, verander die verhouding tussen die mikrobes in die korrels tot so 'n mate dat 'n nuwe mikrobiese gemeenskap saamgestel word. Die gevolgtrekking is ook gemaak dat tradisionele metodes saam met nuwer metodes gebruik moet word in die bepaling van hierdie mikrobiese gemeenskap.

Kefir é um alimento fermentado resultante da dupla fermentação do leite pelos grãos de kefir, sendo estes grãos uma associação simbiótica de leveduras, bactérias ácido-láticas e bactérias ácido-acéticas. Do kefir pode-se obter o kefir leban e o soro de kefir, ambos resultantes da filtração do kefir em tecido de algodão esterilizado, por 24 horas, a 25ºC ± 2ºC. Este estudo tem por objetivos caracterizar e avaliar o comportamento de diferentes amostras de grãos de kefir tradicional e de derivados (kefir, kefir leban e soro de kefir) quanto às características físico-químicas, sensoriais, intenção de compra e atividade anti-Escherichia coli, quando inoculados em diferentes concentrações, padronizando-se o tipo de leite, o tempo e a temperatura de incubação, a maturação e a filtração. Foram desenvolvidas análises fisicoquímicas, a avaliação sensorial através do teste de aceitabilidade e preferência e a determinação de atividade anti-Escherichia coli. Os resultados demonstraram que a técnica de manipulação e padronização das amostras foi eficaz na obtenção de produtos com características idênticas, visto a reprodutibilidade dos resultados. Também indicam que o volume de leite utilizado na incubação influencia significativamente nas características do produto final. O kefir leban obtido do experimento apresentou consistência cremosa, semelhante ao queijo quark, aroma característico de laticínio fermentado, cor amarela esbranquiçada, sabor ácido e boa espalhabilidade. Manteve os teores de cálcio contidos no leite após o processamento, concentrou as proteínas e gorduras, além de não conter lactose. Apresentou boa aceitabilidade e 58% de intenção de compra, quando utilizado na elaboração de formulações alimentares tipo antepasto. O kefir e o soro de kefir apresentaram Intensidade de Atividade de Inibição Bacteriana/bacteriostasia e Intensidade de Atividade de Inativação Bacteriana/ bactericidia máximas frente ao inóculo bacteriano Escherichia coli (ATCC 11229), testado em concentrações <=108 UFC/mL. / Kefir is a fermented food resulting from the double fermentation of milk by kefir grains, these grains are a symbiotic association of yeasts, acid-lactic and acetic-acid bacteria. From kefir can be obtained kefir leban and kefir whey, both from the filtration of kefir in sterile cotton cloth, during 24 hours at 25°C ± 2ºC. This study aims to characterize and evaluate the behavior of different samples of traditional kefir grains and products derived (kefir, kefir leban and kefir whey) on the physicochemical composition, sensorial characteristic, intent to buy and anti-Escherichia coli activity, when inoculated in different concentrations, standardized the type of milk, the time and temperature of incubation, the maturation and filtration processes. Were developed physical and chemical analysis, the sensory evaluation using the tests of acceptability and preference and determination of anti-Escherichia coli activity. The results showed that the technique of handling and standardizing of the samples was effective in providing products with similar characteristics as the reproductibility of results. It is also indicate that the volume of milk used in the incubation influence significantly the characteristics of the final product. The kefir leban obtained in the experiment showed creamy consistency, similar to quark cheese, characteristic aroma of fermented dairy, whitish yellow color, acid flavor and good spread. He maintained the calcium contained in milk after processing,he concentrated protein, and don't contain any lactose. The product showed good acceptability and 58% of purchase intention, when used in the preparation of food formulations such hors d'oeuvre. The kefir and the kefir whey showed maximal intensity of bacterial inhibition activity/bacteriostasys, and intensity of bacterial inactivation activity/bactericidie in front of inoculum of Escherichia coli (ATCC 11229), tested at concentrations <=108CFU/mL.

Master of Science / Food Science Institute / Kadri Koppel / Yogurt drinks have seen a 66% increase in consumption over the last 5 years. Even though there has been an increase in yogurt drink consumption, the market share of drinkable dairy beverages remains small. Carbonated dairy beverages have become increasingly popular in recent years and innovations in this area could help drive increased consumption of these beverages. Currently traditionally carbonated dairy beverages, like kefir, are the most popular carbonated dairy beverages on the market. Carbonation at appropriate levels in dairy products, especially dairy beverages, has been shown to improve the sensory attributes, quality, and shelf life of these products. Probiotics, which are added to yogurt drinks for their health benefits, are not harmed or negatively affected by carbonation. Several methods have been developed to carbonate dairy beverages in a manufacturing setting, although these methods have not been widely applied to commercially available products. The increased consumption of dairy beverages and the benefits of carbonation upon these beverages means that there are opportunities to develop a widely accepted and popular carbonated dairy beverages. The objective of this article was to review available literature on carbonated dairy beverages and to discuss challenges and opportunities in this area.

Kefir é um alimento fermentado resultante da dupla fermentação do leite pelos grãos de kefir, sendo estes grãos uma associação simbiótica de leveduras, bactérias ácido-láticas e bactérias ácido-acéticas. Do kefir pode-se obter o kefir leban e o soro de kefir, ambos resultantes da filtração do kefir em tecido de algodão esterilizado, por 24 horas, a 25ºC ± 2ºC. Este estudo tem por objetivos caracterizar e avaliar o comportamento de diferentes amostras de grãos de kefir tradicional e de derivados (kefir, kefir leban e soro de kefir) quanto às características físico-químicas, sensoriais, intenção de compra e atividade anti-Escherichia coli, quando inoculados em diferentes concentrações, padronizando-se o tipo de leite, o tempo e a temperatura de incubação, a maturação e a filtração. Foram desenvolvidas análises fisicoquímicas, a avaliação sensorial através do teste de aceitabilidade e preferência e a determinação de atividade anti-Escherichia coli. Os resultados demonstraram que a técnica de manipulação e padronização das amostras foi eficaz na obtenção de produtos com características idênticas, visto a reprodutibilidade dos resultados. Também indicam que o volume de leite utilizado na incubação influencia significativamente nas características do produto final. O kefir leban obtido do experimento apresentou consistência cremosa, semelhante ao queijo quark, aroma característico de laticínio fermentado, cor amarela esbranquiçada, sabor ácido e boa espalhabilidade. Manteve os teores de cálcio contidos no leite após o processamento, concentrou as proteínas e gorduras, além de não conter lactose. Apresentou boa aceitabilidade e 58% de intenção de compra, quando utilizado na elaboração de formulações alimentares tipo antepasto. O kefir e o soro de kefir apresentaram Intensidade de Atividade de Inibição Bacteriana/bacteriostasia e Intensidade de Atividade de Inativação Bacteriana/ bactericidia máximas frente ao inóculo bacteriano Escherichia coli (ATCC 11229), testado em concentrações <=108 UFC/mL. / Kefir is a fermented food resulting from the double fermentation of milk by kefir grains, these grains are a symbiotic association of yeasts, acid-lactic and acetic-acid bacteria. From kefir can be obtained kefir leban and kefir whey, both from the filtration of kefir in sterile cotton cloth, during 24 hours at 25°C ± 2ºC. This study aims to characterize and evaluate the behavior of different samples of traditional kefir grains and products derived (kefir, kefir leban and kefir whey) on the physicochemical composition, sensorial characteristic, intent to buy and anti-Escherichia coli activity, when inoculated in different concentrations, standardized the type of milk, the time and temperature of incubation, the maturation and filtration processes. Were developed physical and chemical analysis, the sensory evaluation using the tests of acceptability and preference and determination of anti-Escherichia coli activity. The results showed that the technique of handling and standardizing of the samples was effective in providing products with similar characteristics as the reproductibility of results. It is also indicate that the volume of milk used in the incubation influence significantly the characteristics of the final product. The kefir leban obtained in the experiment showed creamy consistency, similar to quark cheese, characteristic aroma of fermented dairy, whitish yellow color, acid flavor and good spread. He maintained the calcium contained in milk after processing,he concentrated protein, and don't contain any lactose. The product showed good acceptability and 58% of purchase intention, when used in the preparation of food formulations such hors d'oeuvre. The kefir and the kefir whey showed maximal intensity of bacterial inhibition activity/bacteriostasys, and intensity of bacterial inactivation activity/bactericidie in front of inoculum of Escherichia coli (ATCC 11229), tested at concentrations <=108CFU/mL.

Kefir é um alimento fermentado resultante da dupla fermentação do leite pelos grãos de kefir, sendo estes grãos uma associação simbiótica de leveduras, bactérias ácido-láticas e bactérias ácido-acéticas. Do kefir pode-se obter o kefir leban e o soro de kefir, ambos resultantes da filtração do kefir em tecido de algodão esterilizado, por 24 horas, a 25ºC ± 2ºC. Este estudo tem por objetivos caracterizar e avaliar o comportamento de diferentes amostras de grãos de kefir tradicional e de derivados (kefir, kefir leban e soro de kefir) quanto às características físico-químicas, sensoriais, intenção de compra e atividade anti-Escherichia coli, quando inoculados em diferentes concentrações, padronizando-se o tipo de leite, o tempo e a temperatura de incubação, a maturação e a filtração. Foram desenvolvidas análises fisicoquímicas, a avaliação sensorial através do teste de aceitabilidade e preferência e a determinação de atividade anti-Escherichia coli. Os resultados demonstraram que a técnica de manipulação e padronização das amostras foi eficaz na obtenção de produtos com características idênticas, visto a reprodutibilidade dos resultados. Também indicam que o volume de leite utilizado na incubação influencia significativamente nas características do produto final. O kefir leban obtido do experimento apresentou consistência cremosa, semelhante ao queijo quark, aroma característico de laticínio fermentado, cor amarela esbranquiçada, sabor ácido e boa espalhabilidade. Manteve os teores de cálcio contidos no leite após o processamento, concentrou as proteínas e gorduras, além de não conter lactose. Apresentou boa aceitabilidade e 58% de intenção de compra, quando utilizado na elaboração de formulações alimentares tipo antepasto. O kefir e o soro de kefir apresentaram Intensidade de Atividade de Inibição Bacteriana/bacteriostasia e Intensidade de Atividade de Inativação Bacteriana/ bactericidia máximas frente ao inóculo bacteriano Escherichia coli (ATCC 11229), testado em concentrações <=108 UFC/mL. / Kefir is a fermented food resulting from the double fermentation of milk by kefir grains, these grains are a symbiotic association of yeasts, acid-lactic and acetic-acid bacteria. From kefir can be obtained kefir leban and kefir whey, both from the filtration of kefir in sterile cotton cloth, during 24 hours at 25°C ± 2ºC. This study aims to characterize and evaluate the behavior of different samples of traditional kefir grains and products derived (kefir, kefir leban and kefir whey) on the physicochemical composition, sensorial characteristic, intent to buy and anti-Escherichia coli activity, when inoculated in different concentrations, standardized the type of milk, the time and temperature of incubation, the maturation and filtration processes. Were developed physical and chemical analysis, the sensory evaluation using the tests of acceptability and preference and determination of anti-Escherichia coli activity. The results showed that the technique of handling and standardizing of the samples was effective in providing products with similar characteristics as the reproductibility of results. It is also indicate that the volume of milk used in the incubation influence significantly the characteristics of the final product. The kefir leban obtained in the experiment showed creamy consistency, similar to quark cheese, characteristic aroma of fermented dairy, whitish yellow color, acid flavor and good spread. He maintained the calcium contained in milk after processing,he concentrated protein, and don't contain any lactose. The product showed good acceptability and 58% of purchase intention, when used in the preparation of food formulations such hors d'oeuvre. The kefir and the kefir whey showed maximal intensity of bacterial inhibition activity/bacteriostasys, and intensity of bacterial inactivation activity/bactericidie in front of inoculum of Escherichia coli (ATCC 11229), tested at concentrations <=108CFU/mL.

A crescente busca por uma alimentação mais saudável e com valor agregado aumenta a necessidade de desenvolvimento de pesquisas que visem não só conhecer os alimentos, como também desenvolver e caracterizar novos produtos. Assim é fundamental que profissionais da área técnica que atuam em indústrias de alimentos e em institutos de pesquisa, trabalhem em conjunto com os profissionais da área da saúde, contribuindo para a prevenção de doenças e promoção da saúde da população. O objetivo geral do estudo foi elaborar e avaliar a atividade antibacteriana in loco de derivados lácteos elaborados a partir de grãos de kefir frente a microrganismos padrão de interesse em alimentos; e determinar a composição físico-química e microbiológica dos produtos. Inicialmente duas formulações de leite fermentado kefir (kefir 1 e 2) foram elaboradas, a primeira com leite pasteurizado e grãos de kefir e a segunda com leite pasteurizado, leite em pó e grãos de kefir. A composição centesimal e de minerais foi avaliada no leite utilizado como matéria-prima e nas formulações de leite fermentado, onde determinou-se também o pH e foi realizada a contagem de bactérias láticas totais. Com base na composição centesimal do kefir, foi verificada a possibilidade de atribuição de propriedade nutricional ao alimento e a conformidade em relação ao regulamento técnico de identidade e qualidade dos leites fermentados. Na sequencia, duas formulações de queijo (Q1 e Q2) e soro (S1 e S2) de kefir foram elaboradas a partir da coagulação microbiana realizada com grãos de kefir e determinada a composição centesimal e o pH. Cinco diferentes densidades populacionais de Staphylococcus aureus (ATCC 25923) e Escherichia coli (ATCC 11229) referidas no estudo como A, B, C, D e E (sendo A > B > C > D > E) foram inoculadas nas formulações de kefir, queijo e soro, sendo determinada a atividade antibacteriana in loco após 0, 24, 48 e 72 horas de confronto. Paralelamente cinco lotes de dez marcas comerciais de leite pasteurizado e leite UHT foram avaliados quanto à conformidade em relação à legislação de rotulagem e aos padrões de identidade e qualidade estabelecidos pela legislação brasileira. As formulações de kefir apresentaram atividade antibacteriana significativa frente às diferentes densidades populacionais dos patógenos em estudo após de 24 horas de exposição, não sendo observada atividade antibacteriana entre 24 e 72 horas de confronto. Kefir 1 e 2 atenderam aos parâmetros físico-químicos e microbiológicos previstos no regulamento técnico de identidade e qualidade de leites fermentados avaliados no estudo. A formulação 1 pode receber a declaração de “fonte de proteínas”, “reduzido em calorias” e “baixo teor de sódio” e a formulação 2 de “alto conteúdo de proteínas”, “baixo teor de sódio” e “alto conteúdo de zinco”. As formulações de queijo e soro de kefir também apresentaram atividade antibacteriana frente aos microrganismos alimentares testados, principalmente após 24 horas de confronto. A atividade antibacteriana foi mais intensa frente à Escherichia coli (ATCC 11229), obtendo-se atividade antibacteriana máxima após 48 e 72 horas de confronto de Q1, Q2, S1 e S2 com diferentes densidades populacionais do microrganismo testadas. As formulações do soro de kefir foram as que apresentaram maior atividade antibacteriana quando comparadas com o kefir e o queijo. Todas as marcas comerciais de leite avaliadas estavam em conformidade com a legislação brasileira de rotulagem. Uma marca de leite pasteurizado integral e três marcas de leite UHT integral não atenderam aos parâmetros mínimos de identidade e qualidade em pelo menos dois dos cinco lotes avaliados, apontando falhas no processo de beneficiamento. Mais pesquisas relacionadas à qualidade dos alimentos e aos derivados lácteos obtidos mediante o emprego de grãos de kefir são indicadas, explorando aspectos sensoriais, físico-químicos e microbiológicos destes alimentos, ampliando sua utilização em dietas. / The growing demand for a healthier and value-added food increases the need for research that aims not only to know food, but also to develop and characterize new products. So it is essential that technical professionals working in the food industry and research institutes to work together with health professionals, contributing to the prevention of disease and promotion of health. The overall objective of the study was to develop and evaluate the in loco antibacterial activity of dairy products made from kefir grains against standard foodborne; and to determine the physicochemical and microbiological characteristics of these products. Initially two formulations of kefir fermented milk (kefir 1 and 2) were prepared, the first with pasteurized milk and kefir grains and the second with pasteurized milk, powdered milk and kefir grains. The chemical and mineral composition of raw material (milk and powdered milk) and kefir products was evaluated, and were also determined the pH and the total lactic acid bacteria count. Based on the chemical composition of kefir, there was verified the possible nutritional property statements and also the compliance of the products with the standards of identity and quality for fermented milks. In sequence, two cheese formulations (Q1 and Q2) and serum (S1 and S2) of kefir were prepared from microbial coagulation made with kefir grains and determined the chemical composition and pH. Five different bacterial densities of Staphylococcus aureus (ATCC 25923) and Escherichia coli (ATCC 11229) referred as A, B, C, D and E (where A> B> C> D> E) were inoculated in kefir, cheese and whey formulations and determined the in loco antibacterial activity after 0, 24, 48 and 72 hours of confrontation. Five batches of ten commercial brands of pasteurized and UHT milk were evaluated according to the rules for labeling and the identity and quality standards established by the Brazilian food law. The kefir formulations showed significant antibacterial activity against different population densities after 24 hours of exposure and no antibacterial activity was observed between 24 and 72 hours of confrontation. Kefir 1 and 2 met the physicochemical and microbiological parameters established by the technical regulation of identity and quality of fermented milks. Formulation 1 fit the nutrition claims "source of protein", "low calories" and "low sodium", and kefir 2 "high protein content", "low sodium" and "high zinc content". The cheese formulations and kefir whey also showed antibacterial activity against the microorganisms, especially after 24 hours of confrontation. The antibacterial activity was more pronounced against Escherichia coli (ATCC 11229), with highest antibacterial activity after 48 and 72 hour confrontation of different population densities with Q1, Q2, S1 and S2. The kefir whey formulations showed higher antibacterial activity than kefir and cheese. All trademarks evaluated were in accordance with the Brazilian food labeling regulations. One pasteurized milk brand and three whole UHT milk brands did not meet the minimum standards of identity and quality in at least two of the five lots assessed, indicating flaws in the production process. More research related to quality of food and dairy products obtained through the use of kefir grains are indicated by exploring sensory, physicochemical and microbiological aspects of these foods, what could expand its use in diets.

A crescente busca por uma alimentação mais saudável e com valor agregado aumenta a necessidade de desenvolvimento de pesquisas que visem não só conhecer os alimentos, como também desenvolver e caracterizar novos produtos. Assim é fundamental que profissionais da área técnica que atuam em indústrias de alimentos e em institutos de pesquisa, trabalhem em conjunto com os profissionais da área da saúde, contribuindo para a prevenção de doenças e promoção da saúde da população. O objetivo geral do estudo foi elaborar e avaliar a atividade antibacteriana in loco de derivados lácteos elaborados a partir de grãos de kefir frente a microrganismos padrão de interesse em alimentos; e determinar a composição físico-química e microbiológica dos produtos. Inicialmente duas formulações de leite fermentado kefir (kefir 1 e 2) foram elaboradas, a primeira com leite pasteurizado e grãos de kefir e a segunda com leite pasteurizado, leite em pó e grãos de kefir. A composição centesimal e de minerais foi avaliada no leite utilizado como matéria-prima e nas formulações de leite fermentado, onde determinou-se também o pH e foi realizada a contagem de bactérias láticas totais. Com base na composição centesimal do kefir, foi verificada a possibilidade de atribuição de propriedade nutricional ao alimento e a conformidade em relação ao regulamento técnico de identidade e qualidade dos leites fermentados. Na sequencia, duas formulações de queijo (Q1 e Q2) e soro (S1 e S2) de kefir foram elaboradas a partir da coagulação microbiana realizada com grãos de kefir e determinada a composição centesimal e o pH. Cinco diferentes densidades populacionais de Staphylococcus aureus (ATCC 25923) e Escherichia coli (ATCC 11229) referidas no estudo como A, B, C, D e E (sendo A > B > C > D > E) foram inoculadas nas formulações de kefir, queijo e soro, sendo determinada a atividade antibacteriana in loco após 0, 24, 48 e 72 horas de confronto. Paralelamente cinco lotes de dez marcas comerciais de leite pasteurizado e leite UHT foram avaliados quanto à conformidade em relação à legislação de rotulagem e aos padrões de identidade e qualidade estabelecidos pela legislação brasileira. As formulações de kefir apresentaram atividade antibacteriana significativa frente às diferentes densidades populacionais dos patógenos em estudo após de 24 horas de exposição, não sendo observada atividade antibacteriana entre 24 e 72 horas de confronto. Kefir 1 e 2 atenderam aos parâmetros físico-químicos e microbiológicos previstos no regulamento técnico de identidade e qualidade de leites fermentados avaliados no estudo. A formulação 1 pode receber a declaração de “fonte de proteínas”, “reduzido em calorias” e “baixo teor de sódio” e a formulação 2 de “alto conteúdo de proteínas”, “baixo teor de sódio” e “alto conteúdo de zinco”. As formulações de queijo e soro de kefir também apresentaram atividade antibacteriana frente aos microrganismos alimentares testados, principalmente após 24 horas de confronto. A atividade antibacteriana foi mais intensa frente à Escherichia coli (ATCC 11229), obtendo-se atividade antibacteriana máxima após 48 e 72 horas de confronto de Q1, Q2, S1 e S2 com diferentes densidades populacionais do microrganismo testadas. As formulações do soro de kefir foram as que apresentaram maior atividade antibacteriana quando comparadas com o kefir e o queijo. Todas as marcas comerciais de leite avaliadas estavam em conformidade com a legislação brasileira de rotulagem. Uma marca de leite pasteurizado integral e três marcas de leite UHT integral não atenderam aos parâmetros mínimos de identidade e qualidade em pelo menos dois dos cinco lotes avaliados, apontando falhas no processo de beneficiamento. Mais pesquisas relacionadas à qualidade dos alimentos e aos derivados lácteos obtidos mediante o emprego de grãos de kefir são indicadas, explorando aspectos sensoriais, físico-químicos e microbiológicos destes alimentos, ampliando sua utilização em dietas. / The growing demand for a healthier and value-added food increases the need for research that aims not only to know food, but also to develop and characterize new products. So it is essential that technical professionals working in the food industry and research institutes to work together with health professionals, contributing to the prevention of disease and promotion of health. The overall objective of the study was to develop and evaluate the in loco antibacterial activity of dairy products made from kefir grains against standard foodborne; and to determine the physicochemical and microbiological characteristics of these products. Initially two formulations of kefir fermented milk (kefir 1 and 2) were prepared, the first with pasteurized milk and kefir grains and the second with pasteurized milk, powdered milk and kefir grains. The chemical and mineral composition of raw material (milk and powdered milk) and kefir products was evaluated, and were also determined the pH and the total lactic acid bacteria count. Based on the chemical composition of kefir, there was verified the possible nutritional property statements and also the compliance of the products with the standards of identity and quality for fermented milks. In sequence, two cheese formulations (Q1 and Q2) and serum (S1 and S2) of kefir were prepared from microbial coagulation made with kefir grains and determined the chemical composition and pH. Five different bacterial densities of Staphylococcus aureus (ATCC 25923) and Escherichia coli (ATCC 11229) referred as A, B, C, D and E (where A> B> C> D> E) were inoculated in kefir, cheese and whey formulations and determined the in loco antibacterial activity after 0, 24, 48 and 72 hours of confrontation. Five batches of ten commercial brands of pasteurized and UHT milk were evaluated according to the rules for labeling and the identity and quality standards established by the Brazilian food law. The kefir formulations showed significant antibacterial activity against different population densities after 24 hours of exposure and no antibacterial activity was observed between 24 and 72 hours of confrontation. Kefir 1 and 2 met the physicochemical and microbiological parameters established by the technical regulation of identity and quality of fermented milks. Formulation 1 fit the nutrition claims "source of protein", "low calories" and "low sodium", and kefir 2 "high protein content", "low sodium" and "high zinc content". The cheese formulations and kefir whey also showed antibacterial activity against the microorganisms, especially after 24 hours of confrontation. The antibacterial activity was more pronounced against Escherichia coli (ATCC 11229), with highest antibacterial activity after 48 and 72 hour confrontation of different population densities with Q1, Q2, S1 and S2. The kefir whey formulations showed higher antibacterial activity than kefir and cheese. All trademarks evaluated were in accordance with the Brazilian food labeling regulations. One pasteurized milk brand and three whole UHT milk brands did not meet the minimum standards of identity and quality in at least two of the five lots assessed, indicating flaws in the production process. More research related to quality of food and dairy products obtained through the use of kefir grains are indicated by exploring sensory, physicochemical and microbiological aspects of these foods, what could expand its use in diets.