Comparação entre métodos de referência e eletrônico por citometria de fluxo na contagem bacteriana total (CBT) e de células somáticas (CCS) em leite submetido a diferentes tratamentos térmicos

• Ano de defesa: 2008
• Autor(a) principal: Deborah Teixeira Evangelista
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Minas Gerais
• Palavras-chave em Português: Veterinária; Leite Análise; Leite Qualidade; Citometria de fluxo; Leite Bacteriologia; leite pasteurizado; contagem de células somáticas; leite cru; citometria de fluxo; contagem bacteriana total; leite esterilizado
• Link de acesso: https://hdl.handle.net/1843/FRPO-7KXJ23

Nowadays, Brazilian dairy sector is facing a period of significant changes in which milk quality is one the main requirements. The official lab net applies either reference or rapid analytical methods in order to research parameters related to milk quality, such as: composition, bacterial count, somatic cell count, and presence of antimicrobial residues. However, considering that some reference methods are long-lasting and show restrictions coupled with the demand to proceed the analysis of a great number of samples, the official lab net has applied alternative approaches, whose results are reliable and obtained in a shorter period of time. The rapid analytical method is based on flux citometry to determine the counts of total bacteria and somatic cells. The present work aimed to deeply study the flux citometry principle as well as verify the correlation between the reference methods (standard plate count and direct microscopy) and the rapid approach (flux citometry) applied to counts of bacteria and somatic cells in raw, pasteurized, and sterilized milks. Randomized blocks design was used and the results were compared according to the test of Tukey. In the work conditions, results from direct microscopy showed a high correlation with those from standard plate count, so that it may be an alternative mean to calibrate the IBC Bactocount equipment to the analysis of raw milk samples by flux citometry. Compared to the other reference methods, flux citometry was able to detect higher bacterial cont in raw, pasteurized, and sterilized milks. Thermal treatments caused different influence on the bacterial counts when results of standard plate count, direct microscopy, and flux citometry were evaluated. Regarding the somatic cell count, direct microscopy showed a high correlation with flux citometry. The thermal treatments did not influence the somatic cell count of both pasteurized and sterilized milk samples, when flux citometry was applied