Application of Lactobacillus casei CRL705 for biopreservation of refrigerated meat under vacuum

CASTELLANO, P., VIGNOLO, G

Jaén, España

Conferencia; Food safety under extreme conditions... a conference on small scale production units of traditional fermented foods; 2004

The inhibitory effects of the protective culture Lactobacillus casei CRL705 and its bacteriocins were studied in vacuum-packaged fresh meat stored at 2ºC during 36 days. L. casei CRL705, isolated from dry sausages produce two bacteriocins; lactocin 705 (active against other lactic acid bacteria and Brochothrix thermosphacta) and lactocin AL705 (anti-Listeria) was applied to beef discs at a concentration of 106 cfu/ml using a spraying bottle. On the other hand lactocin 705, a two-components bacteriocin, purified and synthesized and lactocin AL705 partially purified were added to meat discs at a concentration of 2.8 mM and 6400 AU/ml, respectively. Listeria monocytogenes (103 cfu/ml) and B. thermosphacta (102 cfu/ml) were co-inoculated with L. casei CRL705 and the bacteriocins. Controls without protective culture and bacteriocins were also included. Results showed that in the uninoculated samples B. thermosphacta grew up 105 cfu/cm2 while in the meat discs inoculated with the protective culture and lactocin 705, this spoilage organism decreased its gowth in 1.25 and 1.55 log cycles, respectively. Addition of the bacteriocinogenic strain and lactocin AL705 to the meat samples did not allow the growth of L. monocytogenes showing a bacteriostatic effect during 36 days of storage. In contrast, L. monocytogens reached a cell counts of 106 cfu/cm2 when grown alone. pH values in the samples inoculated with L. casei CRL705 and the bacteriocins did not presented significant differences when compared to the uninoculated ones. Antimicrobial activity was detected along the 36 days of storage, this being the responsible of the growth suppression of B. thermosphacta and L. monocytogenes. These results suggest that L. casei CRL705 used as a protective culture was able to growth and produce bacteriocins at low temperature and under vacuum being as efficient as the bacteriocins assuring the microbiological stability and safety of meat.   Keywords: Biopreservation, bacteriocins, lactocin 705, lactocin Al705, meat.