ANALYSIS OF THE ANTI-Listeria monocytogenes ACTIVITY OF ENTEROCINS AND A COMMERCIAL CURING SALT

C. IBARGUREN; M.CECILIA SORIA; G.REYES; AUDISIO CARINA

Encuentro; 3ra Reunión conjunta de Sociedades Argentinas de Biología de la República Argentina; 2015

Hurdle technology involves the application of multiple conservation methods designed to prevent bacterial contamination in food in order to improve the product safety and quality. The aim of this work was to compare the anti-Listeria monocytogenes effect of enterocins present in the cell-free supernatant (CFS) of Enterococcus avium DSMZ17511 and a commercial curing salt (Embutir, Salta-Argentina). An adaptation of the chessboard technique was used. Aliquots (2700 ul) of the antimicrobial pair dilutions tested were placed on the ordinate (SLC: 1280, 256 and 128 AU/mL) and the abscissa (salt: 0.03, 0.015 and 0.003% w/v) of a 12-well microplate. Then, an aliquot (300 ul) of a suspension of L. monocytogenes 01/155 was added to each well and the survival of the pathogen in each system was monitored at 37°C during 24 h (t0, 4 and 24 h) by plate counting. A control growth of the strain in peptone water was also included. When the pathogen grew in contact with the three salt concentrations tested, its viability remained similar to the control growth throughout the experiment. No growth of the Listeria strain was detected in systems containing CFS, except the well where the lowest concentration of enterocins (128 AU/mL) and curing salt (0.003% w/v) was combined. These results confirm the anti-L. monocytogenes activity of the enterocins tested, even at low concentrations; while the curing salt analyzed was not effective against the pathogen tested, even when concentrations over the upper limit set for this food additive by the Argentine Food Codex were assayed.