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 heat resistant molds in tomato pulp packed aseptically

This work aimed at determining the occurrence of heat resistant molds during the aseptic processing of tomato pulp (8° BRIX). During tomato harvest, 9 lots were sampled (3 at the beginning, 3 at the apex and 3 at the end of harvest) and other 5 lots were sampled between harvest. For each lot, the enumeration of heat resistant molds was carried out in samples collected during the aseptic process. The mean count of heat resistant molds was relatively low, ranging from <1 to 8CFU/100mL of sample. The higher counts were observed in the raw material and the pre-wash and transportation water. Fifty strains of heat resistant molds detected in the enumeration procedure were isolated, codified and stocked. One-month-old spores of each isolate were submitted to different heat shocks to select the most heat resistant mold. The most heat resistant isolated strain (survived 100° C/25 minutes) was identified as Neosartorya fischeri.Este trabalho teve como objetivo principal determinar a ocorrência de fungos filamentosos termo-resistentes durante o processamento asséptico de polpa de tomate (8° BRIX). Durante o período de safra de tomate foram feitas amostragens em 9 lotes (3 no início, 3 no pico e 3 em fim de safra) e no período de entresafra em 5 lotes. Foi feita a enumeração de fungos termo-resistentes nas amostras coletadas durante as diferentes etapas do processo asséptico de cada lote. Foram obtidas contagens médias relativamente baixas, variando entre <1 e 8UFC/100mL de amostra. As maiores contagens foram obtidas na matéria prima e na água de pré lavagem e transporte. Cinqüenta linhagens de fungos termo-resistentes detectadas no procedimento de enumeração foram isoladas, codificadas e estocadas. Os esporos de cada isolado com 1 mês de cultivo foram submetidos a diferentes choques térmicos para selecionar a linhagem de fungo mais termo-resistente. O isolado de fungo mais termo-resistente (sobrevivência ao choque à 100° C/25 minutos) foi identificado como Neosartorya fischeri.25826