RESUMO
The efficiency of mitochondrial DNA (mtDNA) restriction analysis and random amplification of polymorphic DNA (RAPD)-PCR to characterize yeasts growing on dry-cured Iberian ham was evaluated. Besides, the distribution of the main species and biotypes of yeasts in the different ripening areas of this product was investigated. MtDNA restriction analysis allowed yeast characterization at species and strain level. RAPD-PCR with the primers (GACA)(4) and (GAC)(5) was inappropriate for characterization at species level. Most of the mtDNA restriction patterns detected in dry-cured Iberian ham were consistent with Debaryomyces hansenii. Several yeasts biotypes were associated to specific geographic areas of dry-cured Iberian ham ripening.
Assuntos
DNA Fúngico , DNA Mitocondrial/genética , Microbiologia de Alimentos , Carne/microbiologia , Técnica de Amplificação ao Acaso de DNA Polimórfico , Mapeamento por Restrição/métodos , Leveduras/genética , Animais , Primers do DNA , Geografia , Músculo Esquelético/microbiologia , Técnicas de Tipagem Micológica , Reação em Cadeia da Polimerase , Técnica de Amplificação ao Acaso de DNA Polimórfico/métodos , Saccharomycetales/classificação , Saccharomycetales/genética , Especificidade da Espécie , Suínos , Leveduras/classificaçãoRESUMO
BACKGROUND: To improve the quality of processed grass carp (Ctenopharyngodon idellus) products and control the accumulation of hazardous substances therein, minced grass carp slices were salted for 6 h at room temperature and then inoculated with mixed starter cultures of Lactobacillus casei, Streptococcus lactis, Saccharomyces cerevisiae Hansen and Monascus anka and fermented for 12 h at 30 degrees C. The changes in some characteristics and biogenic amine contents of the fermented muscles were investigated. RESULTS: During the 12 h fermentation at 30 degrees C, muscles inoculated with mixed starter cultures showed a rapid decrease in pH from 6.0 to 5.1 and suppression of the growth of enterobacteria and pseudomonads. The fermented muscles exhibited better colour, appearance, flavour and overall acceptability than the control (P < 0.05). The changes in non-protein nitrogen and free amino acid contents of the fermented muscles and in their sodium dodecyl sulfate polyacrylamide gel electrophoresis profiles indicated that severe hydrolysis of muscle proteins occurred during fermentation. The accumulation of biogenic amines in the muscles was efficiently reduced by fermentation with mixed starter cultures. CONCLUSION: Fermentation with mixed starter cultures of L. casei, S. lactis, S. cerevisiae Hansen and M. anka significantly improved the characteristics of grass carp muscles and controlled the accumulation of biogenic amines.
Assuntos
Bactérias , Aminas Biogênicas/metabolismo , Carpas/metabolismo , Produtos Pesqueiros , Microbiologia de Alimentos , Conservação de Alimentos , Músculo Esquelético/metabolismo , Aminoácidos/metabolismo , Animais , Bactérias/crescimento & desenvolvimento , Bactérias/metabolismo , Carpas/microbiologia , Contagem de Colônia Microbiana , Cor , Eletroforese em Gel de Poliacrilamida , Fermentação , Produtos Pesqueiros/microbiologia , Produtos Pesqueiros/normas , Proteínas de Peixes/metabolismo , Humanos , Concentração de Íons de Hidrogênio , Hidrólise , Músculo Esquelético/microbiologia , Nitrogênio/metabolismo , PaladarRESUMO
Footpad lesions of 3 nude mice infected by Mycobacterium leprae were studied at 9, 12, and 14 months after inoculation with light and electron microscope. The lesions were somewhat similar to those found in nodules in polar lepromatous leprosy. Striated muscles rather than nerves were the preferred site of the growth of M. leprae. Yet, M. leprae were identified in Schwann cells and endothelial cells, singly and in clumps. M. leprae filled macrophages, and free M. leprae were found in large numbers in the endoneurium without producing any significant demyelination.