Tratamientos combinados de altas presiones y bioconservación en la mejora de la seguridad microbiológica de productos cárnicos listos para el consumo

Abstract

The demand for ready-to-eat (RTE) products has increased among consumers during last years. Listeria monocytogenes, Salmonella Enteritidis and Escherichia coli O157:H7 might contaminate these products during their manufacture, becoming a risk for consumers, especially in temperature abuse conditions. High hydrostatic pressure (HHP) treatments were combined with bacteriocins, the lactoperoxidase system (LPS) or lactoferrin (LF), in an attempt to potentiate possible antimicrobial synergistic effects and minimize the severity of treatments against microorganisms mentioned above on sliced dry-cured ham and beef carpaccio. In dry-cured ham, HHP at 400, 500 and 600 MPa for 5 min inactivated S. Enteritidis for 60 d at 8 ºC. A synergistic antimicrobial effect was achieved with 500 MPa and nisin on E. coli O157:H7 and with 450 MPa/10 min and the LPS or LF against S. Enteritidis. Biopreservatives applied alone did not have an effect on these pathogen levels. In beef carpaccio, HHP at 450 MPa for 5, 10 or 15 min were effective to inactivate S. Enteritidis for 30 d at 8 ºC. Synergistic antimicrobial effects were detected with 450 MPa/5 min and the LPS against S. Enteritidis and E. coli O157:H7 and with 450 MPa/5min combined with enterocins A and B, pediocin PA-1 or commercial nisin against E. coli O157:H7. Commercial pediocin was effective against L. monocytogenes. Color and texture of both products were slightly affected by treatments. The antimicrobial effect of acidified nitrite combined with a HHP treatment at 225 MPa or 300 MPa for 8 min in vitro was synergistic on L. monocytogenes and E. coli, respectively. The bactericidal activity of nitrite was pH dependent. The E. coli BW25113 hmpA and norV mutants were more sensitive to nitrite and HHP than wild-type E. coli.