Navegando por Autor "Perin, Luana Martins Perin"

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Protocols for the isolation and detection of lactic acid bacteria with bacteriocinogenic potential
(LWT - Food Science and Technology, 2010-11) Moraes, Paula Mendonça; Perin, Luana Martins Perin; Ortolani, Maria Beatriz Tassinari; Yamazi, Anderson Keizo; Viçosa, Gabriela Nogueira; Nero, Luís Augusto
The objective of this study was to evaluate culture media and methodologies for isolation and detection of lactic acid bacteria (LAB) capable to produce bacteriocin-like substances. Samples of milk and cheese were pour plated on de Mann-Rogosa-Sharpe agar (MRS) and Kang-Fung-Sol agar (KFS) (both at 35 °C/48 h, under anaerobiosis), from which 389 and 256 LAB cultures were selected. The antagonistic activity of them was evaluated using the spot-on-the-lawn and two culture media: brain-heart infusion agar with catalase (BHI + C) and M17 (both at 35 °C/24 h). The proteinaceous nature of the antagonistic cultures was verified using: spot-on-the-lawn (MRS, 25 °C/24 h, under anaerobiosis) and well-diffusion (cultures amplified on modified MRS broth at 25 °C/24 h, and then neutralized using NaOH). Listeria monocytogenes ATCC 7644 was used as indicator. A larger number of antagonist cultures were isolated from MRS (83 by M17 and 65 by BHI + C) in comparison to KFS (24 by M17 and 15 by BHI + C). The spot-on-the-lawn identified a higher frequency of LAB capable of producing bacteriocin-like substances. MRS was considered to be the best culture media for the isolation of LAB capable to produce bacteriocin-like substances, activity that was better identified using the spot-on-the-lawn methodology.