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almeida_ao_dr_jabo.pdf: 1938959 bytes, checksum: aa6e71c37ae1f2bd9af5352672e1bbff (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Este trabalho buscou definir e padronizar uma metodologia simples e rápida para ser utilizada na indicação da segurança de consumo de leite pasteurizado. Foram analisadas 261 amostras de leite recém-pasteurizado de diferentes marcas comerciais, as quais foram submetidas à prova rápida de redução em tubos, aos métodos microbiológicos oficiais de controle (contagem padrão em placas de mesófilos, determinação do número mais provável (NMP) de coliformes totais e fecais) e às pesquisas de atividade enzimática (peroxidase e fosfatase alcalina). Padronizou-se a prova rápida em tubos partindo de diluições decimais das amostras, misturando-as ao Cloreto de Trifeniltetrazólio (TTC) e a um meio nutritivo à base de leite desnatado. As leituras foram realizadas a cada 30 minutos até completar 8 horas de incubação, observando-se a formação de cor pela redução do TTC. Comparou-se os resultados da prova rápida com os da contagem padrão em placas de mesófilos e com o NMP de coliformes (total e fecal), demonstrando uma elevada correlação linear (r = -0,85). A maioria das amostras que se encontrava fora dos padrÕes regulamentares tinha peroxidase positiva classificadas como reações P++ e P+++. Do total, 134 amostras (51,3%) foram consideradas dentro dos padrões regulamentares para ambos os métodos microbiológicos oficiais, embora oito dessas tenham reduzido o TTC em até 8 horas. Dentre as 127 amostras (49,7%) que estavam fora dos padrões regulamentares, 93 reduziram o TTC em até 8 horas de leitura... / The objective of this study was to define and to standardize a sim pie and rapid methodology to be used in the indication of the security of pasteurized milk consumption. In this work, 261 fresh-pasteurized milk samples, of different commercial brands, were submitted to a rapid test of reduction in tubes and to the official microbiological methods of control (standard plate count of mesophilic aerobic bacteria, determination of the most probable number (MPN) of total and fecal coliforms) and to the research of enzymatic activity (peroxidase and alkaline phosphatase). It was standardized rapid test in tubes leaving of decimal dilutions of the samples, mixing them it the Triphenyltetrazolium Chloride (TTC) and to a nutritional medium containing skimmed milk. The readings were realized to each 30 minutes until completing 8 hours of incubation, observing themselves it formation of color for the reduction of the TTC. The results of the fast test were compared with the ones of the standard plate count of mesophilic and with the MPN of coliforms (total and fecal), demonstrating a high degree of linear correlation (r = -0,85). Most of the samples that was found outside of established pattern had peroxidase positive as reactions P++ and P+++. Of the total, 134 samples (51.3%) were considered inside of the established limits for both the official microbiological methods, even so eight of these have reduced the TTC in up to 8 hours. Amongst the 127 samples (49.7%) that were over the established pattern, 93 had reduced the TTC in up to 8 hours of reading. The fast reduction test in tubes was able to detect bacterial counts loading from 104 UFC/mL of tested sample, with 72,2%... (Complete abstract click electronic access below)
| Identifer | oai:union.ndltd.org:IBICT/oai:repositorio.unesp.br:11449/94642 |
| Date | 27 November 2006 |
| Creators | Almeida, Adriana Oliveira de [UNESP] |
| Contributors | Universidade Estadual Paulista (UNESP), Prata, Luiz Francisco [UNESP] |
| Publisher | Universidade Estadual Paulista (UNESP) |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | Portuguese |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/masterThesis |
| Format | ix, 92 f. : il. |
| Source | Aleph, reponame:Repositório Institucional da UNESP, instname:Universidade Estadual Paulista, instacron:UNESP |
| Rights | info:eu-repo/semantics/openAccess |
| Relation | -1, -1 |
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