Evaluación de la acción anti-Listeria monocytogenes de nisina inmovilizada en arcilla. Efecto del pH del medio de reacción

C. IBARGUREN; M. C. AUDISIO; E. L. SHAM; E. M. FARFÁN TORRES

Córdoba

Congreso; IV Congreso Internacional de Ciencia y Tecnología de los Alimentos; 2012

Universidad Nacional de Córdoba - CICYTAC

A natural alternative for Listeria monocytogenes surveillance in foods is the application of bacteriocins of lactic acid bacteria as biopreservantes. To avoid adverse interactions with the food matrix, different supports have been proposed for the addition of bacteriocins. This study evaluated the listericide activity of nisin immobilized on natural montmorillonite (MMT) and studied the effect of the reaction medium pH value on the antimicrobial activity of the immobilized peptide. Aliquots of a nisin solution (0.025 g/ml) adjusted to different pH values (2-7) were put in contact (2h, 25 ºC) with MMT fractions dispersed in water (0.30% wMMT/v). The resulting pellets were suspended in aliquots of a fresh culture of L. monocytogenes 01/155 adjusted to the appropriate pH values and the viability of the pathogen was traced. Also, the survival of the pathogen in peptone water adjusted to the same pH values was determined. After 6h, the viability of the pathogen in contact with NIS MMT-systems (pH 2-7) decreased in similar way, while the acid individually inhibitory action was variable. This study confirmed the anti-L. monocytogenes effect of nisin immobilized on MMT without the detection of significative implications of the medium pH on this inhibitory action.