No description available.

Water and a copper sulfate (CSL) solution at 27, 57 and 88°C; steam pasteurization and dielectric heating were analyzed on their effect in reducing microbial load (APC) and Salmonella Typhimurium on inshell pecans (Carya illinoinensis). The CSL solution (more effective than water alone) reduced APC by 1.5 (300 s), 2 (60 s) and 4.0 (60 s) log CFU/g at 27, 57 and 88°C, respectively; and Salmonella by 3.0 log at 27°C in 60 s. Steam reduced APC by 3.7 log in 180 s and Salmonella by 4.0 log CFU/g in 30 s. Dielectric treatment reduced APC by 3.0 log and Salmonella by 4.5 log CFU/g in 60 s. Most treatments had no effect on the pecan shell or the nut quality, except for dielectric heating, which gave a slight "roasted" or "burnt" flavor to the nuts. This study showed that a proper antimicrobial-hot water treatment, steam or dielectric heating will be effective in "pasteurizing" pecans, resulting in a safe and wholesome product.

No description available.

The objective of this study was to determine amount and composition of waste milk (WM) generated by 13 dairy farms and to measure effectiveness of on-farm pasteurizers. Waste milk was sampled bi-weekly from three farms located in North Carolina (NC) for 28 weeks and twice from ten farms in California (CA) in June 2005 and Jan. 2006. Amount of waste milk generated ranged from 2.48 – 9.84 L/calf/d. Standard plate count (SPC) of waste milk before pasteurization averaged 17 million cfu/ml on NC farms and 1.6 million cfu/ml on CA farms. Pasteurizers failed to deactivate alkaline phosphatase in 16%, and <5% of the time in NC and CA. California WM had lower post pasteurized SPC (13,000 cfu/ml) than NC farms (430,000 cfu/ml). A feeding trial was conducted to evaluate supplementing WM with 28% protein: 20% fat milk replacer (28:20) when WM is insufficient relative to calf demands. Treatment (TRT) 1 calves received M for 28d and then 28:20 until weaning at 56d. Treatment 2 calves received 28:20 for 28d and then milk until weaning. Treatment 3 calves received 28:20 for the entire period Four periods of time were evaluated; the total period, first four weeks (P1), transition period (TP), in which calves were switching diets, and until weaning (P2). Treatment 1 ADG was higher during TP as compared to TRT 2. Results demonstrated that similar growth rates through 8 weeks of age was achieved with either combination of M and 28:20 or only 28:20 fed on an isocaloric basis. / Master of Science

Master of Science

Submitted by Jorge Silva (jorgelmsilva@ufrrj.br) on 2018-08-23T21:04:05Z No. of bitstreams: 1 2009 - Monique Lopes Ribeiro.pdf: 2169069 bytes, checksum: d331284a6463585cb4755e8e93b90be8 (MD5) / Made available in DSpace on 2018-08-23T21:04:05Z (GMT). No. of bitstreams: 1 2009 - Monique Lopes Ribeiro.pdf: 2169069 bytes, checksum: d331284a6463585cb4755e8e93b90be8 (MD5) Previous issue date: 2009-03-27 / CAPES / Brazil is responsible for 25 % of total papaya production in the world, a fruit wich is mainly characterized for its nutritional aspects. The juice and pulp industries have showed an increase in their production in the last years. However, this segment takes only 5% of total papaya produced, while the remaining is consumed as a fresh fruit. This scene is unfavorable, because the high rate of losses during times of big harvests. The processing of papaya can minimize the losses, increasing its shelf life and adding value to this tropical fruit. One of the most used conservation method is HTST pasteurization (high temperature, short time), wich reduces microbial count to safe levels for the consumers and inactivates pectinesterase. This enzyme has an important role during fruit ripening, but it becomes undesirable after process, because acts in pectin and causes undesirable changes in the pulp. The main objective of this study was investigate the effects of temperature and process time on the pectinesterase activity in papaya Formosa pulp. The effects of thermal process on the physical and chemical, nutritional, microbiological and sensorial characteristics were also evaluated. The experiments were carried out following a 22 factorial design with central point. Two independents variables were studied, temperature and time, in the range of 75 to 95?C / 20 to 60 s. The results were submitted to analyses of variance with 95% of confidence interval. In the range of study, factors temperature, process time and interaction did not show significant effects in the characteristics such as pH, titratable acidity, soluble solids contents, vitamin B1, B2 and C contents, antioxidant activity, phenolic compounds, carotenoids contents and colour parameters (L, a, b e ?E). Temperature showed a positive significant (p<0,05) linear effect in the reduction of pectinesterase activity. The best time and temperature ranges for heat processing, which reached more than 95 % of enzyme inactivation were between 20 and 60 seconds at 95?C. The process at 95 ? C/ 60 s promoted a significant decrease in vitamin C content, compared to fresh pulp (Dunnett test at 5% probability level), while the other nutrients did not show significant losses. The presence of coliforms at 45 ?C and Salmonella was not detected. The applied treatments were sufficient to promote a reduction of about 3 logarithmic cycles in the population of molds and yeasts. The Preference Map obtained by the acceptance analyses showed a trend of preference for the pasteurized at 95 ?C / 60 s, 95 ?C / 20 s and fresh samples, while commercial pulps were rejected by consumers. / O Brasil ? respons?vel por 25% do total da produ??o mundial de mam?o, um fruto que se caracteriza principalmente por seus aspectos nutricionais. A ind?stria de sucos e polpas tem apresentado um aumento na sua produ??o nos ?ltimos anos. Entretanto, este segmento aproveita somente 5 % do total de mam?o produzido, sendo o restante consumido in natura. Este quadro ? desfavor?vel tendo em vista os altos ?ndices de perdas nas ?pocas de grandes safras. O processamento em forma de polpa minimiza as perdas, pois aumenta a vida ?til e agrega valor econ?mico ao fruto. Um dos tratamentos mais aplicados para a polpa de mam?o ? a pasteuriza??o do tipo HTST (High Temperature, Short Time), cuja finalidade ? reduzir a carga microbiana a n?veis seguros para os consumidores e inativar a enzima pectinesterase. Esta enzima, que tem um papel fundamental na matura??o do fruto, se torna indesej?vel ap?s o processamento, pois atua sobre a pectina causando altera??es indesej?veis na polpa. Este trabalho teve como principal objetivo avaliar o efeito da temperatura e tempo de processo na atividade da enzima pectinesterase presente na polpa de mam?o Formosa. Tamb?m foram avaliados os efeitos do tratamento t?rmico nas caracter?sticas microbiol?gicas, f?sico-qu?micas, nutricionais e sensoriais da polpa. Os experimentos foram realizados seguindo um planejamento fatorial completo 22 com ponto central, sendo as vari?veis independentes o tempo e a temperatura de processo, em uma faixa de observa??o entre 75 ?C e 90 ?C / 20 s e 60 s. Os dados foram submetidos ? an?lise de vari?ncia com intervalo de confian?a de 95 %. Na faixa observada, tanto os fatores tempo e temperatura como a intera??o entre os fatores n?o apresentaram efeitos significativos nas caracter?sticas como pH, acidez titul?vel, teor de vitamina B1, teor de vitamina B2, teor de vitamina C, teor de caroten?ides, atividade antioxidante, teor de compostos fen?licos e par?metros da cor (L, a, b e ?E). O fator temperatura apresentou um efeito linear significativo (p < 0,05) e positivo para redu??o da atividade da pectinesterase, sendo que os tratamentos a 95 ?C / 20 s e 95 ?C / 60 s foram os que apresentaram maior percentual de redu??o, com aproximadamente 95 %. Em compara??o ? polpa in natura, somente a polpa submetida a 95 ?C / 60 s apresentou um decr?scimo significativo no teor de vitamina C (pelo teste de Dunnett ao n?vel de 5 %), sendo que para os outros nutrientes n?o houve decr?scimo significativo. Nas an?lises microbiol?gicas n?o foi detectada a presen?a de coliformes a 45 ?C e de Salmonella sp. Os tratamentos aplicados promoveram uma redu??o na ordem de 103 na contagem total de fungos e leveduras. Na an?lise sensorial, o Mapa Interno de Prefer?ncia obtido a partir dos dados de aceita??o mostraram uma tend?ncia ? prefer?ncia pelas amostras pasteurizadas a 95 ?C / 60 s, 95 ?C / 20 s e in natura, enquanto que as polpas de marcas comerciais foram rejeitadas.

O presente trabalho objetivou descrever o comportamento da cepa Salmonella Enteritidis (S. Enteritidis) PT4, frente ao tratamento térmico a 60,0º C por três minutos e meio, em ovo integral pasteurizado desidratado reconstituído, interrelacionando a termorresistência com temperatura prévia de incubação e concentração de microrganismos. Foram realizadas 150 análises, das quais 75 foram trabalhadas com cepa previamente incubada à 35ºC e 75 com cepa incubada à 43ºC. Cada um destes grupos foi subdividido em três subgrupos, inoculado-se as concentrações de 10³, 105 e 108 unidades formadoras de colônia (UFC)/mL de caldo BHI. Após inoculação, foi simulada pasteurização do ovo, a 60,0ºC por 3,5 minutos, em banho-maria, e, posteriormente, realizadas contagem em placa (UFC) e Número Mais Provável (NMP), para verificação da concentração de S. Enteritidis sobrevivente. O tempo de redução decimal (valor D) foi de 2,54 e 2,57 minutos para S. Enteritidis previamente incubada à 35ºC e inoculada nas concentrações de 105 e 108 UFC/mL de caldo BHI, respectivamente. Para S. Enteritidis previamente incubada à 43ºC e inoculada nas concentrações de 105 e 108 UFC/mL de caldo BHI, o valor D foi de 2,58 e 2,40 minutos, respectivamente. Não foi possível o cálculo do valor D para a concentração 10³ UFC/mL de caldo BHI, visto que não houve população sobrevivente. Não houve diferença significativa entre os resultados de contagem e NMP, comparando-se as duas temperaturas de incubação, entretanto, os resultados de contagem e NMP das três concentrações inoculadas foram diferentes entre si. Concluiu-se que a cepa pré incubada a 43ºC não apresentou maior resistência ao calor, em relação à cepa incubada a 35ºC; e não houve maior resistência ao calor, comparando-se as diferentes concentrações. / The purpose of this study was to describe the behavior of Salmonella Enteritidis (S. Enteritidis) PT4 undergoing thermal treatment at 60ºC for 3 ½ minutes in reconstituted dried-whole egg, correlating the heat resistance with a previous temperature of incubation and microrganism concentration. 150 analyses were conducted, 75 with S. Enteritidis PT4 previously incubated at 35ºC and 75 with S. Enteritidis PT4 previously incubated at 43ºC. Each of these two groups was subdivided in 3 sub-groups, adding the inoculum at concentrations of 10³, 105, 108 CFU/mL of BHI broth. After the inoculation, pasteurization of the egg was simulated at 60ºC for 3,5 minutes in a water bath. Then colony count and Most Probable Number (MPN) were carried out to check the concentration of surviving S. Enteritidis. The decimal reduction time (D-value) was 2.54 and 2.57 minutes for S. Enteritidis previously incubated at 35ºC and inoculated in the concentration of 105 and 108 CFU/mL of BHI broth, respectively. Concerning the S. Enteritidis previously incubated at 43ºC and inoculated in concentrations of 105 and 108 CFU/mL of BHI broth, the D-value was 2.58 and 2.40 minutes, respectively. It was not possible to calculate the D-Value for the 10³ CFU/mL concentration of BHI broth, because there was no surviving population. There was no significant difference between the results of colony count and MPN, comparing the two incubation temperatures, however the results of colony count and MPN of the three inoculated concentrations were different from each other. It was possible to conclude that the S. Enteritidis PT4 previously incubated at 43ºC hadn´t shown more heat resistance if compared with the S. Enteritidis PT4 incubated at 35ºC; and there wasn’t more heat resistance, comparing the different concentrations.

No description available.

The biogas plant Kungsängens gård, owned by Uppsala Vatten och Avfall AB, produces biogas and biomanure from organic household waste, food processing waste and slaughterhouse waste. In year 2012, 4.4 million Nm3 of biogas were produced from 25 200 tons of waste. Before digestion all substrate is sanitized by pasteurization at 70°C in order to kill pathogens. Another method, integrated thermophilic sanitation (ITS), is of interest in order to decrease the energy demand. The method implies that the substrate is sanitized during ten hours in the digestion chamber, where the temperature is 52°C. The purpose of this thesis was to compare pasteurization with integrated thermophilic sanitation from an energy point of view. The pasteurization´s impact on biogas production and energy yield was examined through experiments with two laboratory digesters, of which one was fed with pasteurized substrate and the other with non-pasteurized substrate. For the present pasteurization system, electricity and heat demand was surveyed. For the integrated thermophilic sanitation, a process design was developed and dimensioned and the electricity and heat demand was calculated. Thereafter, the energy yield and energy demand for the two sanitation systems were compared. The result showed that pasteurization had no effect on biogas production. The energy yield was on average 4.79 kWh/kg VS from non-pasteurized substrate and 4.74 kWh/kg VS from pasteurized substrate. There was no statistically significant difference between the reactors. The energy audit showed that pasteurization required 0.48 kWh/kg VS, which is 85 % of the total energy consumption at the facility. The digester warming demanded 0.077 kWh/kg VS for RK1 and 0.031 kWh/kg VS for RK2. The electricity consumption was 0.041 kWh/kg VS. The process of ITS was designed with a heat exchange from bio manure to substrate, followed by heating to 52°C by steam addition. The heat requirement was 0.24 kWh/kg VS and the electricity demand was 0.034 kWh/kg VS. The warming of the digesters was the same as in the present pasteurization system. The comparison between the existing pasteurization and the ITS showed that switching systems would save 0.243 kWh/kg VS or 46 % of the present energy consumption. This corresponds to annual savings of 1.22 GWh. A sensitivity analysis showed that the results were sensitive to assumptions regarding the heat exchanger in the case of ITS. 10 % energy losses resulted in smaller savings, 34 % or 0.91 GWh per year. There are increased risks of process disruptions if ITS is combined with an increased organic loading rate. 4.2 % reduction of the total biogas production erases the energy savings which means that it is important that process stability is ensured.

Made available in DSpace on 2014-06-11T19:27:21Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-03-02Bitstream added on 2014-06-13T18:56:01Z : No. of bitstreams: 1 sartori_lca_me_jabo.pdf: 309501 bytes, checksum: f65ecbb362c11cf287ceffd861806be4 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A mastite representa um dos mais sérios problemas existentes nas fazendas de leite. Os objetivos deste estudo foram identificar leveduras envolvidas nos casos de mastite bovina; avaliar a sensibilidade in vitro de cepas de Candida spp. frente a quatro desinfetantes utilizados no pré e pós-dipping e avaliar a resistência destas leveduras frente à pasteurização e fervura. Cinquenta e cinco amostras (12,8%) foram positivas para o gênero Candida. As espécies mais isoladas foram C. krusei (34,6%), C. parapsilosis (25,4%), C. tropicalis (18,2%) e C. albicans (12,8%). As drogas utilizadas foram clorexidina (2,0%), iodo (0,8%), iodo glicerinado (0,8%) e hipoclorito de sódio (1,0%) em 4 intervalos específicos de tratamento (15″, 30″, 60″ e 300″). Cem por cento das cepas de Candida foram sensíveis a clorexidina nos tempos de 30″, 60″ e 300″, ao iodo glicerinado em 60″ e 300″, ao hipoclorito de sódio em 60″ e 300″ e ao iodo apenas em 300″. Em relação aos tratamentos térmicos, a pasteurização rápida foi o procedimento no qual houve maior índice de resistência (64,44%) por parte das estirpes de leveduras. A mastite provocada por fungos está se tornando um problema crescente devido ao aumento da participação deste microrganismo no desenvolvimento de mastite em bovinos. Além disso, resistência apresentada ao tratamento térmico pelas cepas de Candida representa um problema para o consumo de leite, significando um risco para a saúde pública. Uma conclusão adicional é a importância da realização periódica de avaliações de sensibilidade dos microrganismos aos desinfetantes utilizados, de forma a garantir a eficácia da desinfecção dos tetos / Mastitis is one of the most serious problems in dairy farms. The objectives of this study were to identify yeasts involved in cases of bovine mastitis; evaluate the in vitro susceptibility of strains of Candida spp. Against four disinfectants used in the pre and post-dipping and evaluate the resistance of these strains before pasteurization and boiling. Fifty-five samples (12,8%) were positive for Candida. The most isolated species were C. krusei (34,6%), C. parapsilosis (25,4%), C. tropicalis (18,2%) and C. albicans (12,8%). As active drugs were used chlorhexidine (2,0%), iodine (0,8%), glycerin iodine (0,8%) and sodium hypochlorite (1,0%) at specific intervals of four treatment (15, 30, 60 and 300). One hundred percent of Candida was found to be sensible to chlorhexidine at 30″, 60″, and 300″, to iodine glycerin at 60″ and 300″, to sodium hypochlorite at 60″, and 300″, to iodine only at 300″. In relation to thermal treatments, pasteurization was the quick procedure in which there was a higher resistance index (64,44%) by yeast strains. Moreover, t he resistance of Candida spp. strains after thermal treatment presents a problem for milk consumption what represents a potential risk for public health. A further conclusion was that it is important to undertake a periodic evaluation of the sensibility of microorganisms to the disinfectants commonly used, to guarantee the efficacy of the process of teat disinfecting