Banca de DEFESA: JÉSSICA DA SILVA CAMPOS
Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.DISCENTE : JÉSSICA DA SILVA CAMPOS
DATA : 26/02/2019
HORA: 14:00
LOCAL: Sala de videoconferência do POP-RN - localizado no Centro de Convivência da UFRN.
TÍTULO:
PHENOTYPIC, GENOTYPIC AND TERMORRESISTENCE EVALUATION OF ISOLATED YEAST OF IN NATURA MILK.
PALAVRAS-CHAVES:
Milk; Yeasts; Candida; Pasteurization slow; Pasteurization, Boiling
PÁGINAS: 83
GRANDE ÁREA: Ciências Biológicas
ÁREA: Microbiologia
SUBÁREA: Microbiologia Aplicada
ESPECIALIDADE: Microbiologia Médica
RESUMO:
Milk is considered an excellent culture medium because it is conducive to the growth of several microorganisms. Thus, ingestion of fresh milk may constitute a potential route of transmission of zoonoses, which justifies the need for microbiological analysis for human consumption. Among the main contaminants of fresh milk, yeasts of the genus Candida, which are associated with infections in humans and animals, and other species also capable of causing opportunistic mycoses such as Kluyveromyces marxianus, Pichia manshurica, Kodamaea ohmeri. In this study, 23 samples of fresh milk type B, collected by manual or mechanical milking were collected and stored in collective refrigeration tanks of farms located in the Metropolitan Region of Natal and nearby. Twenty samples of fresh milk commercially traded in the city of Ceará-Mirim were also analyzed. In order to establish the phenotypic, genotypic, quantitative and thermo-resistant characterization of yeasts isolated from fresh milk, we also sought to trace the susceptibility profile of the isolates to the antifungal agents. Positive samples were analyzed for quantification by count of Colony Forming Units (CFU). All isolated species were treated by slow pasteurization (62-64 ° C / 30 minutes) and fast (72-75 ° C / 20 seconds), as well as by boiling. Fifty yeast strains of the species were characterized: C. tropicalis 14 (28%), C. parapsilosis 7 (14%), C. albicans 6 (12%), C. glabrata 5 (10%), C. krusei 5 (10%), Kluyveromyces. marxianus 5 (10%), C. guilliermondii 4 (8%), C. rugosa 1 (2%), C. parapsilosis 1 (2%), C. orthopsilosis 1 (2%), Pichia manshurica 1 (2%), Kodamaea ohmeri 1 (2%). Five isolates showed resistance to the antifungal agents tested. A global median of 37 x 102 CFU / mL was obtained, 33 x 102 UFC / mL in the milk collected by manual milking and 80.5 x 102 UFC / mL in the milk collected by mechanical milking. The milk in natura marketed in Ceará-Mirim showed a median of 20 x102 CFU / mL. Of the isolates submitted to heat treatment, 80% were resistant to fast pasteurisation and 60% to boiling, but none of them resisted slow pasteurisation. It was concluded that the milk collected through mechanical milking and stored in collective cooling tanks, presented higher rates of yeast contamination, compared to milk samples collected by manual milking and kept under the same storage conditions. Boiling, as well as rapid pasteurization, which are procedures widely used to reduce the contamination of milk and its derivatives, have not proved to be efficient for this purpose. On the other hand, the slow pasteurisation proved to be 100% efficient for the elimination of contaminating yeasts from the evaluated milk samples.
MEMBROS DA BANCA:
Presidente - 2121234 - VANIA SOUSA ANDRADE
Interno - 348473 - JOSE VERISSIMO FERNANDES
Interna - 1452833 - MARIA CELESTE NUNES DE MELO
Externo à Instituição - MARIA APARECIDA RESENDE STOIANOFF - UFMG