Caracterização da atividade antimicrobiana e tecnologica de tres culturas bacteriocinogenicas e avaliação de sua eficiencia no controle de Listeria monocytogenes, Staphylococcus aureus e Bacillus cereus em queijo Minas frescal. / Characterization of the antimicrobian and technological activity of three bacterion producing cultures and evaluation of its efficiency in the Listeria monocytogenes, Staphylococcus aureus e Bacillus cereus control in Minas frescal cheese.

AUTOR(ES)
DATA DE PUBLICAÇÃO

2007

RESUMO

The biopreservation system, such as bacteriocinogenic lactic bacteria cultures and/or their bacteriocins, have received increasing attention and new approaches to control pathogenic and spoilage microorganisms have been developed. The purpose of this study was to evaluate the action of bacteriocin-producing cultures (Lactococcus lactis subsp. lactis ATCC 11454, Lactobacillus plantarum ALC 01 and Enterococcus faecium FAIR-E 198) on some Gram-positive pathogens in different culture media and dairy products. The bacteriocin production was influenced by the media. The antimicrobial activity of these cultures was evaluated by agar-well diffusion assay. The bacteriocins produced by Lb. plantarum ALC 01 and E. faecium FAIR-E 198 presented inhibitory activity on Listeria monocytogenes alone, on the other hand, the nisin produced by Lc. lactis subsp. Lactis ATCC 11454 demonstrated wide action spectrum, albeit with lower activity. In compatibility of associative development evaluation with the commercial starter culture, only Lc. lactis subsp. lactis ATCC 11454 presented activity on the starter culture. The acidifier activity determination was carried out in skimmed milk after 8h and 24h of incubation at 35ºC. The addition of 0.1% and 0.5% of the bacteriocinogenic cultures did not affect the production of lactic acid by the starter culture. The associative development of the starter culture with Lb. plantarum ALC 01 and E. faecium FAIR-E 198 provided significant increase in bacteriocin activity of these cultures, while the activity of Lc. Lactis subsp. lactis ATCC 11454 nisin was suppressed. The aminopeptidase activity was determined after cellular lise of the lactic cultures previously grown in MRS broth. Lb plantarum ALC 01 presented the largest activity. Moreover, the behavior of Gram-positive pathogens was analyzed during co-culture with the bacteriocin-producing bacteria and with the starter culture in skimmed milk. Lb. plantarum ALC 01 and E. faecium FAIR-E 198 did not influence the development of Bacillus cereus K1-B041 and of Staphylococcus aureus ATCC 27154 during the first 24h of incubation at 35ºC. They presented strong inhibition on L. monocytogenes Scott A. Lc. lactis subsp. lactis ATCC 11454 affected the development of the pathogens studied during the first 12h of incubation. The starter culture demonstrated good inhibition of B. cereus K1-B041 (>7.37 log UFC/ml) and L monocytogenes Scott A (>6.26 log UFC/ml). In Minas Frescal cheese, significant difference was not observed between the action of the bacteriocinogenic cultures and the starter culture on L. monocytogenes Scott A and S. aureus ATCC 27154. B. cereus K1- B041 demonstrated susceptibility to Lb. plantarum ALC 01 and E. faecium FAIR-E 198 after 7 days. Bacteriocin activity was not detected in the cheeses during 21 days at 8 ± 1ºC. The addition of the bacteriocin-producing bacteria as an adjunct culture to the Minas Frescal cheese did not promote alteration in the pH and in the acidity, however Lb. plantarum ALC 01 and E. faecium FAIR-E 198 promoted an increase of the cheese proteolysis. Although the obtained results demonstrated that bacteriocinogenic cultures cannot be used as only method of conservation, these can be used as an additional barrier to optimize the control of Gram-positive pathogens, especially L. monocytogenes, in dairy products.

ASSUNTO(S)

listeria monocytogenes gram-positive bacteria bacteriocins bacteriocinas queijo lactic acid bacteria bacterias produtoras de acido lactico cheese bacterias gram-positivas

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