CERELA   05438
CENTRO DE REFERENCIA PARA LACTOBACILOS
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
GROWTH CONTROL OF LISTERIA MONOCYTOGENES IN TEMPERATURE ABUSED HAMBURGERS STORED AT 5ºC
Autor/es:
P. CASTELLANO; M. BLANCO; G. VIGNOLO
Lugar:
Rosario, Argentina
Reunión:
Congreso; IV Congreso Argentino de Microbiología General. Sociedad Argentina de Microbiología General; 2008
Resumen:
For more than two decades, Listeria monocytogenes continues to raise food safety concerns especially in ready-to-eat frozen stored products. Apart from the frequent isolation of the pathogen from meat and meat products, various reports have confirmed the implication of such products in listeriosis outbreaks. Bacteriocins or bacteriocin-producing starters were often suggested to be part of the “hurdle technology” to enhance the safety and keeping quality of meat products. Numerous lactic acid bacteria have been described to inhibit L. monocytogenes in vitro and in meat systems. In this work the inhibition effectiveness of Lactobacillus curvatus CRL705 and Lactococus lactis CRL1109 used as bioprotective culture and their bacteriocins, lactocin AL705 (12.800 UA ml-1) and nisin (6.400 UA ml-1) against Listeria monocytogenes (initial inocula 102 CFU g-1) in temperature abused hamburgers stored at 5ºC, was evaluated. The addition of 106 cfu g-1 of each bacteriocinogenic strain to meat did not allow the growth of L. monocytogenes, showing a bacteriostatic effect during 72 h of aerobic storage at 5ºC. No synergistic effect was observed when both bacteriocin-producing strains were used together. However, after the addition of lyophilized bacteriocins to the hamburguers an immediate inhibition of the pathogenic organism in the was observed, while in the control samples L. monocytogenes grew, its number increasing by 1 log cycles. Bacteriocin activity in samples inoculated with the bioprotective cultures as well as with the bacteriocins was detected during all of storage period. These results demonstrated that the added bacteriocins were more effective when compared to the bioprotective cultures inhibiting L. monocytogenes in hamburgers stored at 5ºC during 72 h. The application of bacteriocins produced by L. curvatus CRL705 and L. Lactis CRL1109 as protective agent would provide and additional hurdle to enhance the control of L. monocytogenes in hamburgers stored at abuse temperature of 5ºC.