Bacillus cereus em leite UHT brasileiro

O consumo de leite ultra-alta temperatura (UHT) brasileiro aumentou, durante a última década, de 187 milhões de litros para 4,200 milhões de litros. No processo contínuo de leite UHT o leite é submetido por 2-4 seg a 130-150ºC, em sistemas de escoamento contínuo com refrigeração imediata e envase asséptico em embalagens herméticas. Esta pesquisa teve a finalidade de verificar a incidência da espécie B. cereus, em leite UHT. Em 1998, foi reportado alto índice destes organismos neste produto atingindo 34,14% das amostras analisadas. Além deste fato, existia a necessidade de se estabelece métodos e processos adequados para correta identificação de B. cereus. Assim, a esterilidade comercial de 6.500 embalagens de leite UHT foi estudada, em dois ensaios, após incubação das amostras a 37ºC e 7ºC por dez dias para germinar todos os possíveis esporos e/ou recuperar células vegetativas injuriadas. Após a incubação, foi realizada a medida de pH. Neste sentido, hum mil e trezentas amostras de cada uma de cinco plantas Brasileiras de processo UHT, que operam com injeção direta de vapor produzindo leite integral em embalagens cartonadas, foram investigadas em relação à presença de Bacillus cereus, através de ensaios fenotípicos e genéticos (PCR). Os valores de pH foram diferentes para as amostras analisadas oscilando entre 6,57 e 6,73. Após a estocagem das amostras, somente quatro embalagens suspeitas, com medida de pH abaixo de 6,5 foram analisadas na procura por B. cereus. Não foi detectado B. cereus em nenhuma amostra indicando que o leite integral UHT Brasileiro, das cinco plantas processadoras, não apresenta o microrganismo patogênico. Somente microrganismos deteriorantes foram isolados indicando que dentro do espaço amostral, o leite UHT analisado não representa riscos e problemas de saúde aos consumidores. A Espectroscopia Infravermelha por Transformada de Fourier (FTIR) e a Reação em cadeia da polimerase (PCR) foram consideradas eficientes e devem ser adotadas para confirmar a série bioquímica de B. cereus.Brazilian Ultra High Temperature (UHT) milk consumption has increased during the last decade from 187 to 4,200 million liters. In the continuous UHT process, milk is submitted for 2-4 s to 130-150ºC, in a continuous flow system with immediate refrigeration and aseptical packing in hermetic packages. This research had the purpose to verify the incidence of B. cereus species from the B. cereus group, in UHT milk. In 1998 high indexes of these organisms were reported, reaching 34.14% of the analyzed samples. Beyond this fact, there was the need to establish methods and processes adjusted for correct identification of B. cereus. Thus, commercial sterility tests of 6,500 UHT milk packages were investigated in two assays, after ten days incubation at 37ºC and 7ºC to germinate all possible spores and/or to recuperate injured vegetative cells followed by pH measurement. Samples (1,300 packages each) from five Brazilian UHT plants of whole UHT milk processed by direct steam injection, packaged in carton were investigated for the presence of Bacillus cereus through phenotypic and genetic (PCR) tests. Values of pH were different for the samples, ranging between 6.57 and 6.73. After storage of the samples, only four packages with pH measurement below the lower limit of 6.5 were found and analyzed for the presence of B. cereus. This organism was not detected in any of the samples indicating that the five Brazilian UHT milk processors control pathogenic microorganisms and it can be said that the consumption of UHT milk does not present safety problems to consumers. Fourier Transform Infrared Spectroscopy (FTIR) and PCR tests were efficient and must be adopted to confirm the biochemical series for B. cereus

Isolation and selection of heat resistant molds in the production process of apple nectar

Heat resistant molds are able to survive the pasteurization process applied to apple products. This study aimed at detecting and identifying heat resistant molds during the processing of apple nectar (pH 3.4; 11.6 °Brix) in order to select the most heat resistant mold. The isolation was carried out after heat shock at 70 °C, during 2 hours, and incubation at 30 °C, in PDA (3% agar), where rose bengal was added. The identification of macro and microscopic structures was carried out after incubation in three different media (G25N, CYA, MEA) and temperatures. Different heat shocks, from 80 °C/20 minutes to 97 °C/15 minutes, were applied to select the most heat resistant mold. Eleven strains were selected, of which five were heat-resistant: three strains were isolated from apple and concentrated apple juice and were identified as Neosartorya fischeri; one strain, isolated from apple, was identified as Byssochlamys fulva and one strain, isolated from the product after the first pasteurization, was identified as Eupenicillium sp. The most heat-resistant strains belong to N. fischeri and B. fulva, which were able to survive at 95 °C/20 minutes. Among the six remaining, one was identified as Aspergillus sp., however, none of them was heat resistant.Os fungos filamentosos termorresistentes são capazes de sobreviver aos processos de pasteurização aplicados aos produtos de frutas. Este estudo visou isolar e identificar fungos termorresistentes durante o processamento de néctar de maçã (pH 3,4 e 11,6 °Brix), de forma a selecionar o bolor mais termorresistente. O isolamento foi obtido após choque térmico de 70 °C/2 horas e incubação a 30 °C em PDA (3% de ágar) acrescido de rosa de bengala. A identificação foi baseada na morfologia e nas estruturas micro e macroscópicas observadas após incubação das cepas em três diferentes meios (G25N, CYA e MEA) e temperaturas. O fungo mais termorresistente foi selecionado pela aplicação de choques térmicos (de 80 °C/20 minutos até 97 °C/15 minutos). Foram detectadas 11 linhagens de bolores, sendo 5 termorresistentes. Dentre estas, três cepas, isoladas da matéria-prima e do concentrado de maçã, foram identificadas como Neosartorya fischeri; uma cepa isolada da matéria-prima foi identificada como Byssochlamys fulva, e uma cepa isolada do produto após a primeira pasteurização foi identificada como Eupenicillium sp. As cepas mais resistentes foram as de N. fischeri e B. fulva, que sobreviveram ao tratamento de 95 °C/20 minutos. Dentre as seis cepas restantes, uma foi identificada como Aspergillus sp., entretanto, nenhuma destas apresentou termorresistência.11612

Efeito de diversos fatores na recuperação de esporos ativados de Bacillus coagulans

Orientador : Fumio YokoyaDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos e AgricolaResumo: O resumo poderá ser visualizado no texto completo da tese digitalAbstract: The abstract is available with the full electronic documentMestradoMestre em Ciência de Alimento

Modelamiento de la interfaz de crecimiento/no crecimiento del Alicyclobacillus acidoterrestris CRA 7152 en jugo de naranja como función del pH, temperatura, Brix y concentración de nisina

The growth probability of Alicyclobacillus acidoterrestris CRA 7152 in orange juice was studied in different product conditions. The microorganism response was monitored until 47 days of storage in different conditions of pH (3 to 5.8), soluble solids (11 to 19°Brix), temperature (20 to 54°C) and nisin concentration (0 to 70 IU/ml). Growth/no growth data were modeled by the polynomial logistics regression model. The concordance of the obtained model was 96.3% indicating good fitting of observed data. The results showed fast growth in the conditions 0 IU nisin/ml juice, pH 4.4 and 15ºBrix, at 35ºC. For 70 IU nisin/ml there was no growth, pH 4.4, at 37ºC, up to 47 days of storage. Simple juices (11°Brix) with pHs between 3.5 to 3.7 can keep stable and withstand abuse temperatures up to 36°C, since added in 70IU nisin/ml, extending its shelf life. With 0.05 growth probability and using the logistics model, high pH critical values can be obtained when 50 IU nisin/ml, at 25ºC, are present in the juice, however increases in temperature and decreases in soluble solids concentration make the pH critical values decrease. It is then concluded that nisin incorporation is an alternative for controlling A. acidoterrestris growth in orange juice, as well as the logistics regression model proved to be an important tool for determining the microbial response under critical values of the variables, besides predicting growth probabilities for the different studied conditions.Se estudió la probabilidad de crecimiento del Alicyclobacillus acidoterrestris CRA 7152 en jugo de naranja en diferentes condiciones de producto. La respuesta del microorganismo fue monitoreado hasta 47 días de almacenamiento bajo diferentes condiciones de pH (3 a 5.8), sólidos solubles (11 a 19 °Brix), temperatura (20 a 54 ° C) y concentración de nisina (0 a 70 UI / ml). Los datos de crecimiento/no crecimiento fueron modelados por el modelo de regresión logística. La concordancia del modelo obtenido fue de 96.3% indicando buen ajuste de los datos observados. Los resultados mostraron un rápido crecimiento en condiciones de 0 UI de nisina /ml de jugo, pH 4.4 y 15ºBrix, a 35ºC. Para 70 UI de nisina / ml, pH 4.4 y 37 °C, hasta 47 días de almacenamiento no hubo crecimiento. Jugos simples (11 °Brix) con pH entre 3.5 a 3.7 puede mantenerse microbiológicamente estable hasta 36 °C, desde que adicionado 70 IU de nisina/ml, extendiendo su vida útil. Con 0.05 de probabilidad de crecimiento y usando el modelo logístico, se puede obtenerse altos valores de pH crítico cuando 50 UI de nisina/ml, a 25 ºC, están presentes en el jugo, sin embargo, los incrementos en temperatura y descenso en la concentración de sólidos solubles hace que los valores de pH crítico disminuyan. Se concluye que la incorporación de nisina es una alternativa para controlar el crecimiento de A. acidoterrestris en jugo de naranja, así como el modelo de regresión logístico demostró ser una herramienta importante para determinar la respuesta microbiana en los valores críticos de las variables, además de predecir las probabilidades de crecimiento para las diferentes condiciones estudiadas

Modeling the growth/no growth interface of Alicyclobacillus acidoterrestris CRA 7152 in orange juice as a function of pH, temperature, Brix and nisin concentration

The growth probability of Alicyclobacillus acidoterrestris CRA 7152 in orange juice was studied in different product conditions. The microorganism response was monitored until 47 days of storage in different conditions of pH (3 to 5.8), soluble solids (11 to 19°Brix), temperature (20 to 54°C) and nisin concentration (0 to 70 IU/ml). Growth/no growth data were modeled by the polynomial logistics regression model. The concordance of the obtained model was 96.3% indicating good fitting of observed data. The results showed fast growth in the conditions 0 IU nisin/ml juice, pH 4.4 and 15ºBrix, at 35ºC. For 70 IU nisin/ml there was no growth, pH 4.4, at 37ºC, up to 47 days of storage. Simple juices (11°Brix) with pHs between 3.5 to 3.7 can keep stable and withstand abuse temperatures up to 36°C, since added in 70IU nisin/ml, extending its shelf life. With 0.05 growth probability and using the logistics model, high pH critical values can be obtained when 50 IU nisin/ml, at 25ºC, are present in the juice, however increases in temperature and decreases in soluble solids concentration make the pH critical values decrease. It is then concluded that nisin incorporation is an alternative for controlling A. acidoterrestris growth in orange juice, as well as the logistics regression model proved to be an important tool for determining the microbial response under critical values of the variables, besides predicting growth probabilities for the different studied conditions

Modeling the growth/no growth interface of Alicyclobacillus acidoterrestris CRA 7152 in orange juice as a function of pH, temperature, Brix and nisin concentration

The growth probability of Alicyclobacillus acidoterrestris CRA 7152 in orange juice was studied in different product conditions. The microorganism response was monitored until 47 days of storage in different conditions of pH (3 to 5.8), soluble solids (11 to 19°Brix), temperature (20 to 54°C) and nisin concentration (0 to 70 IU/ml). Growth/no growth data were modeled by the polynomial logistics regression model. The concordance of the obtained model was 96.3% indicating good fitting of observed data. The results showed fast growth in the conditions 0 IU nisin/ml juice, pH 4.4 and 15ºBrix, at 35ºC. For 70 IU nisin/ml there was no growth, pH 4.4, at 37ºC, up to 47 days of storage. Simple juices (11°Brix) with pHs between 3.5 to 3.7 can keep stable and withstand abuse temperatures up to 36°C, since added in 70IU nisin/ml, extending its shelf life. With 0.05 growth probability and using the logistics model, high pH critical values can be obtained when 50 IU nisin/ml, at 25ºC, are present in the juice, however increases in temperature and decreases in soluble solids concentration make the pH critical values decrease. It is then concluded that nisin incorporation is an alternative for controlling A. acidoterrestris growth in orange juice, as well as the logistics regression model proved to be an important tool for determining the microbial response under critical values of the variables, besides predicting growth probabilities for the different studied conditions

Equipamento Para DeterminaÇço De ResistÊncia TÉrmica De Microrganismos E Compostos Sob AÇço De Stress TÉrmico E Cisalhante, MÉtodo De OperaÇço Do Equipamento E Seu Uso

EQUIPAMENTO PARA DETERMINAÇÃO DE RESISTÊNCIA TÉRMICA DE MICRORGANISMOS E COMPOSTOS SOB AÇÃO DE STRESS TÉRMICO E CISALHANTE, MÉTODO DE OPERAÇÃO DO EQUIPAMENTO E SEU USO. A presente invenção se refere a um equipamento para determinação de resistência térmica de microrganismos e compostos sob ação de stress térmico e cisalhante onde o referido equipamento compreende: duas tampas; um copo cilíndrico de diâmetro interno Di; um rotor cilíndrico dediâmetro externo De, onde De é maior ou igual a O,9091*Di com extremidade inferior em forma de cunha circular; orificios de entrada/saída de meio de aquecimento; uma câmara de cisalhamento formada pelo espaço entre o copo e o rotor; uma "Camisa", provida de uma manta de isolamento; e um motor controlado por variação de freqüência. A presente invenção também se refere ao método de operação do equipamento, bem como o uso do mesmo.BRPI1100575 (A2)C12Q1/00G01N3/34G01N33/00G01N33/483BR2011PI00575C12Q1/00G01N3/34G01N33/00G01N33/48

Occurrence of molds on laminated paperboard for aseptic packaging, selection of the most hydrogen peroxide- and heat-resistant isolates and determination of their thermal death kinetics in sterile distilled water

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)This study aimed at enumerating molds (heat-labile and heat-resistant) on the surface of paperboard material to be filled with tomato pulps through an aseptic system and at determining the most heat-and hydrogen peroxide-resistant strains. A total of 118 samples of laminated paperboard before filling were collected, being 68 before and 50 after the hydrogen peroxide bath. Seven molds, including heat-resistant strains (Penicillium variotii and Talaromyces flavus) with counts ranging between 0.71 and 1.02 CFU/cm(2) were isolated. P. variotii was more resistant to hydrogen peroxide than T. flavus and was inactivated after heating at 85 degrees C/15 min. When exposed to 35 % hydrogen peroxide at 25 degrees C, T. flavus (F5E2) and N. fischeri (control) were less resistant than P. variotti (F1A1). P. citrinum (F7E2) was shown to be as resistant as P. variotti. The D values (the time to cause one logarithmic cycle reduction in a microbial population at a determined temperature) for spores of P. variotii (F1A1) and N. fischeri (control) with 4 months of age at 85 and 90 degrees C were 3.9 and 4.5 min, respectively. Although the contamination of packages was low, the presence of heat-and chemical-resistant molds may be of concern for package sterility and product stability during shelf-life. To our knowledge, this is the first report that focuses on the isolation of molds, including heat-resistant ones, contaminating paperboard packaging material and on estimating their resistance to the chemical and physical processes used for packaging sterilization.28726092614Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Microbial modeling of thermal resistance of Alicyclobacillus acidoterrestris CRA7152 spores in concentrated orange juice with nisin addition Modelagem microbiana da resistência térmica de esporos de Alicyclobacillus acidoterrestris CRA7152 em suco de laranja concentrado com adição de nisina

The nisin effect on thermal death of Alicyclobacillus acidoterrestris CRA 7152 spores in concentrated orange juice (64ºBrix) was studied. Concentrations of 0, 50, 75 and 100 IU of nisin/ml juice, at temperatures of 92, 95, 98 and 102ºC were evaluated. The quadratic polynomial model was used to analyze the effects of the factors and their interaction. Verification of surviving spores was carried out through plating in K medium (pH 3.7). The results showed that the D values without nisin addition were 25.5, 12.9, 6.1 and 2.3 min for 92, 95, 98 and 102ºC respectively. With addition of nisin into the juice there was a drop of heat resistance as the concentration was increased at a same temperature. With 30, 50, 75, 100 and 150 IU/ml at 95ºC, the D values were 12.34, 11.38, 10.49, 9.49 and 9.42 min respectively, showing that a decrease in the D value up to 27% can be obtained. The second order polynomial model established with r² = 0.995 showed that the microorganism resistance was affected by the action of temperature followed by the nisin concentration. Nisin therefore is an alternative for reducing the rigor of the A. acidoterrestris CRA 7152 thermal treatment.<br>Estudou-se o efeito da nisina na inativação térmica dos esporos de Alicyclobacillus acidoterrestris CRA 7152 em suco de laranja concentrado (64 ºBrix). Foram avaliadas as concentrações de 0, 50, 75 e 100 UI de nisina/ml de suco nas temperaturas de 92, 95, 98 e 102 ºC. Foi utilizado o modelo polinomial quadrático para analisar os efeitos dos fatores e suas interações. A contagem dos esporos sobreviventes foi feita através de plaqueamento em meio K (pH = 3,7). De acordo com os resultados obtidos encontrouse um valor de D sem adição de nisina de 25,5; 12,9; 6,1 e 2,3 min para as temperaturas de 92, 95, 98 e 102 ºC respectivamente. Quando a nisina foi adicionada ao suco observouse uma queda na resistência térmica em função do aumento da concentração de nisina para os mesmos valores de temperatura. Ao utilizar as concentrações de 30, 50, 75 e 150 IU/ml a 95 ºC, o valor de D obtido foi de 12,34; 11,38; 10,49; 9,49; e 9,42 min respectivamente demonstrando que a adição de nisina provoca um decréscimo de até 27 % no valor de D. O modelo polinomial de segunda ordem ajustado com r² = 0,995 mostrou que a resistência do microorganismo foi afetada pela temperatura seguida da concentração de nisina. A adição de nisina é, portanto, uma alternativa para reduzir o rigor do tratamento térmico em A. acidoterrestris CRA 7152

Inactivation of neosartorya fischeri and paecilomyces variotii on paperboard packaging material by hydrogen peroxide and heat

This study reports on the influence of heat and hydrogen peroxide combination on the inactivation kinetics of two heat resistant molds: Neosartorya fischeri and Paecilomyces variotii. Spores of different ages (1 and 4 months) of these molds were prepared and D-values (the time required at certain temperature/hydrogen peroxide combination to inactivate 90% of the mold ascospores) were determined using thermal death tubes. D-values found for P. variotii ranged from 1.2 to 25.1 s after exposure to different combinations of heat (40 or 60 °C) and hydrogen peroxide (35 or 40% w/w) while for N. fischeri they varied from 2.7 to 14.3 s after exposure to the same hydrogen peroxide concentrations and higher temperatures (60 or 70 °C). The influence of temperature and hydrogen peroxide concentration on the d-values varied with the genus of mold and their ages. A synergistic effect of heat and hydrogen peroxide in reducing D-values of Paecilomyces variotti and N. fischeri has been observed. In addition to strict control of temperature, time and hydrogen concentration, hygienic storage and handling of laminated paperboard material must be considered to reduce the probability of package’s contamination. All these measures together will ensure package’s sterility that is imperative for the effectiveness of aseptic processing and consequently to ensure the microbiological stability of processed foods during shelf-life231165170CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQSem informaçã