Molecular analysis of bacteriocin expression in semi-hard cheeses

NADIA ELINA SUÁREZ; LOURDES CRUZ PINTOS; MARTA NÚÑEZ; MARÍA PÍA TARANTO; LUCILA SAAVEDRA

Mar del Plata

Congreso; 51 Annual Meeting Argentine Society for Biochemistry and Molecular Biology; 2015

Argentine Society for Biochemistry and Molecular Biology

Many lactic acid bacteria are able to secrete ribosomally-synthesized peptides that have antimicrobial activity, knownas bacteriocins. E. faecium CRL1879 is a native strain isolated from an artisanal cheese in the northwestern ofArgentina. This strain displays a remarkable antibacterial activity against L. monocytogenes and has six class IIbacteriocin clusters in its genome. The aim of the present work was to evaluate the expression of enterocin CRL1879genes (entA, entB, entSE-K4, entP, entXαβ, entCRL1879αβ) during the manufacture and storage of a semi-hardcheese by RT-PCR. In addition, this bacteriocin-producing strain was tested with regard to controlling L.monocytogenes growth during the manufacture and storage of semi-hard cheeses. Pilot-scale semi-hard cheesesnamely A (starter culture), B (starter culture + CRL1879), C (starter culture + L.monocytogenes), D (starter culture +CRL1879 + L.monocytogenes) were manufactured in duplicate in the pilot plant according to CERELA protocol.Results demonstrated that E. faecium CRL1879 express all enterocin genes except for enterocin A and SE-K4 duringcheese ripening. Consequently, bacteriocin titration was detectable at 1600 UA/ml during the whole process andcompletely inhibits L. monocytogenes growth during cheese ripening (30 days) at 8°C. E. faecium CRL 1879represents a promising tool for biopresevartion.