Bifidobactérias: isolamento, identificação e aplicação em alimentos probióticos / Bifidobacteria: isolation, identification and use in probiotic foods

Esta revisão de literatura teve por objetivo descrever os principais meios de cultura já desenvolvidos para o isolamento e enumeração de bifidobactérias, e os métodos moleculares utilizados para a identificação desse gênero e de suas espécies. Os critérios de seleção das bifidobactérias probióticas visando à aplicação tecnológica também foram abordados (como tolerância a pH baixo, presença de oxig~enio e presença de ingredientes e aditivos). Diversas pesquisas realizadas com bifidobactérias para o desenvolvimento de alimentos probióticos foram citadas. A importância do isolamento e identificação das bifidobactérias envolve a aplicação desses microorganismos como agentes probióticos em alimentos. Pode-se concluir que a constante busca pela saúde tende a aumentar o consumo de alimentos probióticos, estimulando a diversificação de produtos e a descoberta de novas cepas com essa função.

Viability of Staphylococcus xylosus isolated from artisanal sausages for application as starter cultures in meat products / Viabilidade de Staphylococcus xylosus isoladas de embutidos artesanais para aplicação como cultivos iniciadores em produtos cárneos

Viability of Staphylococcus xylosus isolated from artisanal sausages for application as starter cultures in meat products Viability of Staphylococcus xylosus strains AD1 and U5isolated from natural fermented sausages was investigated as starter cultures in fermented sausages produced in the South Region of Brazil. The study demonstrated that the Staphylococcus xylosus strains AD1 and U5showed significant growth during fermentation, stability over freeze-dried process, negative reaction for staphylococcal enterotoxins and viability for using as a single-strain culture or associated with lactic acid bacteria for production of fermented sausages.

Investigamos a viabilidade de cepas de Staphylococcus xylosus (AD1 e U5) isoladas de embutidos com fermentação natural, para aplicação como cultivos iniciadores em embutidos fermentados produzidos na Região Sul do Brasil. O estudo demonstrou que cepas de Staphylococcus xylosus (AD1 e U5) apresentaram crescimento significativo durante a fermentação, estabilidade no processo de liofilização e conservação, ausência de produção de enterotoxinas e viabilidade para aplicação como cultivo iniciador simples ou associado com bactérias lácticas na elaboração de embutidos fermentados.

Cultivation of Arthrospira (spirulina) platensis in desalinator wastewater and salinated synthetic medium: protein content and amino-acid profile

Arthrospira (Spirulina) platensis was cultivated in laboratory under controlled conditions (30ºC, photoperiod of 12 hours light/dark provided by fluorescent lamps at a light intensity of 140 µmol photons.m-2.s-1 and constant bubbling air) in three different culture media: (1) Paoletti medium (control), (2) Paoletti supplemented with 1 g.L-1 NaCl (salinated water) and (3) Paoletti medium prepared with desalinator wastewater. The effects of these treatments on growth, protein content and amino acid profile were measured. Maximum cell concentrations observed in Paoletti medium, Paoletti supplemented with salinated water or with desalinator wastewater were 2.587, 3.545 and 4.954 g.L-1, respectively. Biomass in medium 3 presented the highest protein content (56.17 percent), while biomass in medium 2 presented 48.59 percent protein. All essential amino acids, except lysine and tryptophan, were found in concentrations higher than those requiried by FAO.

Arthrospira (Spirulina) platensis foi cultivada em laboratório sob condições controladas (30ºC, intensidade luminosa de 140 µmol fótons.m-2.s-1, 12 horas claro/escuro e insuflação constante de ar atmosférico), em três meios de cultivo: (1) meio de Paoletti (controle), (2) meio de Paoletti suplementado com 1,0 g.L-1 de NaCl (água salinizada) e (3) meio de Paoletti preparado com rejeito de dessalinizador. Foi verificado o efeito destes tratamentos no crescimento, teor de proteínas e aminoácidos. As concentrações celulares máximas obtidas foram de 2,587; 3,545 e 4,954 g.L-1 no meio controle, meio de Paoletti suplementado com água salinizada ou com rejeito de dessalinizador, respectivamente. Com relação às concentrações protéicas, estas foram maiores na biomassa cultivada no meio 3, com 56,17 por cento, enquanto que a biomassa cultivada no meio 2 apresentou 48,59 por cento. A maioria dos aminoácidos essenciais encontrou-se acima dos limites requeridos pela FAO, com exceção apenas de lisina e triptofano.

Survival of Listeria monocytogenes in low acid italian sausage produced under brazilian conditions

Dry sausages have been considered ready-to-eat products with low risk of causing listeriosis due to the hurdles created during the manufacturing process such as low pH and a w, high salt concentration and presence of lactic acid bacteria (LAB). However, several studies have detected survival of Listeria monocytogenes in these products and also shown that process parameters, LAB and L. monocytogenes strains directly influence the results. In this work, survival of the pathogen in sausages prepared with three different formulations (one standard formulation, one formulation added of Lactobacillus plantarum and one added of 2 percent sodium lactate), using the manufacturing process usually employed in Brazil, was evaluated. Naturally contaminated sausages presented a small increase in the counts of L. monocytogenes in the first days of the process, followed by a gradual decrease until the end of the process. In experimentally contaminated samples containing L. plantarum, the reduction of counts of L. monocytogenes during processing was considerable, but there wasn´t significant differences between the treatments.

Salames têm sido considerados produtos prontos para o consumo com baixo risco de provocar listeriose devido aos obstáculos criados no processo de fabricação e suas características de pH e atividade água baixos, alta concentração de sal e presença de bactérias lácticas. Entretanto, a sobrevivência de Listeria monocytogenes nesta classe de produtos é verificada e estudos de processo visando à redução da contaminação por este patógeno, têm demonstrado que particularidades como variação dos parâmetros de processo, cepas de bactérias lácticas e de L. monocytogenes influenciam diretamente os resultados. Neste estudo três formulações foram avaliadas (uma padrão, uma com inoculação da cultura Lactobacillus plantarum e outra com adição 2 por cento de lactato de sódio) empregando parâmetros de processo comumente praticados no Brasil. Os salames naturalmente contaminados apresentaram discreto aumento da população de L. monocytogenes no início do processo, seguidos por redução até o final da maturação. Os salames artificialmente contaminados tiveram redução considerável da contagem de L. monocytogenes não havendo diferenças significativas entre os tratamentos.

Aeromonas spp. isolated from oysters (Crassostrea rhizophorea) from a natural oyster bed, Ceará, Brazil

Foram realizadas 30 coletas quinzenais, entre abril e outubro de 2002, de ostras (Crassostrea rhizophorea) de um criadouro natural, no estuário do rio Cocó (Fortaleza/Ceará/Brasil), objetivando-se isolar cepas de Aeromonas spp. As amostras de ostras foram submetidas aos métodos de plaqueamento direto (PD) e presença/ausência (P/A). Foram identificadas Aeromonas em 15 (50%) amostras analisadas pelo método PD e em 13 (43%) pelo método P/A. Foram isoladas: A. caviae, A. eucrenophila, A. media, A. sobria, A. trota, A. veronii bv. sobria, A. veronii bv. veronii e Aeromonas sp. A espécie predominate foi A. veronii (ambos biovars), identificada em 13 (43%) amostras, seguida de A. media em 11 (37%) e A. caviae em 7 (23%). Das 59 cepas identificadas, 28 (48%) apresentaram resistência a pelo menos um, dos oitos antibióticos testados.

Bacteria of fecal origin in mangrove oysters (Crassostrea rhizophorae) in the Cocó River estuary, Ceará State, Brazil

O objetivo deste trabalho foi avaliar a qualidade microbiológica da ostra de mangue (Crassostrea rhizophorae) originária de um criadouro natural no estuário do Rio Cocó, Fortaleza, Ceará, Brasil. Para isso, foram realizadas as estimativas do Número Mais Provável (NMP) de Coliformes Totais (CT) e de Fecais (CF) e de Enterococcus spp. Os valores encontrados para CT e CF no músculo (com líquido intervalvar) variaram de <1,8 a >1.600 e <1,8 a 920 por grama, respectivamente. O valor do NMP de Enterococcus spp. variou de <3,0 a >1.100/g. Não houve correlação entre os parâmetros físico-químicos (temperatura, salinidade e pH) da água na área do criadouro e os níveis de contaminação encontrados nas ostras. Somente houve correlação entre os valores de CT e CF. Cepas de Enterococcus spp. foram isoladas e submetidas a testes bioquímicos para identificação das espécies e, posteriormente, foram testadas para verificar a produção de substância inibitória semelhante à bacteriocina utilizando a cepa-teste Escherichia coli ATCC 25922. De um total de 121 cepas de Enterococcus spp. testadas apenas uma, E. faecalis, apresentou atividade inibitória.

Bacteriocinogenic effect of Lactobacillus sakei 2a on microbiological quality of fermented Sardinella brasiliensis

Lactobacillus sakei 2a is a bacteriocin producer strain and, in this work, it's effects as a starter culture in the fermentation process of sardine (Sardinella brasiliensis) fillets were observed at different concentrations of NaCl (2, 4 and 6 percent) and glucose (2 and 4 percent), to determine it's ability to produce organic acids and consequent pH reduction. Experiments were carried out independently, with only one parameter (NaCl or glucose) varying at a time. After 21 days of fermentation the deteriorative bacteria concentration reached 9.7 Log10 CFU. g-1 corresponding to 6 percent NaCl and 4 percent glucose. Little differences were observed in lactic acid production when 2 and 4 percent glucose were added, since total acidity was 1.32 and 1.34 percent respectively, the experiments with 6 percent NaCl presented the best results. Initial pH of sardine fillets was 6 and after 21 days pH values were 3.8, 3.9 and 4 for the experiments with 2, 4 and 6 percent NaCl. This may have been due to the inhibitory properties of NaCl over the deteriorative bacteria. After 21 days of the fermentation process lactic acid bacteria concentrations were 14.5 Log10 CFU.g-1. The ratio protein nitrogen and total soluble nitrogen was typical of a cured fish

Avaliaçäo de diferentes métodos cromatogrâficos na determinaçäo de ácidos graxos em sementes de maracujá (Passiflora edulis f. flavicarpa) / Differents evaluation of cromatographic methods of determination of fatty acids in seed yelds of maracuja(Passiflora edulis f. flavicarpa)

Determinou-se a composicao de ácidos graxos, por cromatografia em fase gasosa, do óleo da semente do maracujá amarelo (Passiflora edulis f. flavicarpa), em três diferentes tamanhos de frutos (tipo 1=12-15cm; tipo 2 = 7-10cm; tipo 3 = 5-6cm). O rendimento das sementes em relaçäo ao peso dos frutos para os tipos 1, 2 e 3 (5,18; 5,83 e 5, 31 por cento) e para a polpa dos tipos 1 e 3 (12; 17 e 12,67 por cento) näo apresentou diferença entre os tamanhos analisados, com exceçäo do tipo 2 (14,03 por cento) para polpa que evidenciou maior rendimento. A composiçäo em ácidos graxos do óleo da semente do maracujá amarelo, nos três diferentes tamanhos, mostrou predominância de ácidos graxos oléico e linoléico. O método mais adequado para a determinaçäo da composiçäo de ácidos graxos do óleo do maracujá foi o Cd 14c-94/coluna SP 2340 da American Oil Chemists"s Society.

Influence of bacteriocins produced by Lactobacillus Plantarum BN in the shelf-life of refrigerated bovine meat

Sugar cane molasses is a cheap by-product of the sugar cane industry. This product was used for growth and production of bacteriocins by Lactobacillus plantarum BN and evaluated for its potential application in the extension of the shelf-life of raw meat. Bovine meat cubes were dipped in the filtered and neutralized supernatant of the fermented broth (Treatment A) and stored at 5(o)C. Counts of psychrotrophic and mesophilic aerobic microorganisms, pH determination and total acidity were performed on meat cubes after 0, 3, 6, 9, 12 and 15 days. These determinations were also done in cubes dipped in a 6 per cente lactic acid solution (treatment B) and distilled water (treatment C). After 3 days, the counts of psychrotrophic microorganisms in cubes submitted to treatment A, B and C increased 0.38, 1.42 and 2.04 log cycles, respectively. The same happened with mesophilic microorganisms (0.31, 0.33 and 1.04 log cycles increases, respectively). On the sixth day, the psychrotrophic population in samples submitted to treatments A and B were 2.07 and 0.64 log cycles, respectively, lower than in the control samples (treatment C). Mesophilic microorganisms in these samples were 1.58 and 1.12 log cycles, respectively, lower than the controls. On the sixth day, only samples submitted to treatment A presented lower counts than those recommended by ICMSF as quality standards for raw meat (<10(7) CFU/g). After nine days of storage under refrigeration, samples submitted to treatment A still maintained acceptable quality. From the twelfth day on, all samples exceeded the microbial quality limits. These results indicate that dipping of raw meat in filtered sugar cane molasses containing bacteriocins produced by L. plantarum BN may be an interesting technological option to extend the shelf life of refrigerated bovine meat.

Produçäo de Lactobacillus plantarum em Melaço de cana-de-açúcar / Production of Lactobacillus plantarum in sugar cane syrup

Comparative studies of Lactobacillus plantarum were carried out in MRS broth (CONTROL) nd in 3 per cent (w/v) sugar cane blackstrap molasses enriched as follows: 0,5 per cent yeast extract, 0,5 per cent amnonium citrate and 0,5 per cent sodium acetate (Medium 1) and 0,5 per cent yeast extract, 0,5 per cent amnonium citrate, 0,5 per cent sodium acetate, 0,5 per cent amnonium phosphate, 0,2 per cent amnonium citrate, 0,1 per cent Tween 80 and 0,005 per cent manganese sulphate (Medium 2). The experiment was carried out at a 5L fermentor, with 3.5 L as working volume. At the end of the fermentation period MRS presented the highest viable cells production (28.68 per cent log CFU?mL) while in Medium 2 it was 25,80 and in Medium 1 19.36 logCFU/mL., Biomass productivity was 0.0865 g. L elevado a menos 1(control), 0,0768 and 0,0507 g.L elevado a menos 1. h for Medium 2 and Medium 1, respectively. In Medium i total avaiable sugar consume was only 60.11 per cent while in MRS and Medium 2 it was 87,21 per cent and 83,80 per cent, respectively

The growth of micrococcus varians by utilizing sugar cane blackstrap molasses as susbstrate

Comparative studies on the growth of Micrococcus varians were carried out in BHI culture medium (control) as well as in a culture medium with 2(per cent) diluted sugar cane blackstrap molasses, enriched with 0.1 (per cent) yeast extract. The experiment was conducted with three samples of the experimental and control media in a 5 liter fermentor with working volume of 3.5 liters, continuous agitation (150 rpm), 35ñ0.1oC temperature, 0.7 L air. 1-1 medium.min-1, initial pH 7.0ñ 0.2, 24 hour fermentation period, and approximate inoculum of 6.0 log10 CFU/ml. Samples were collected at 2-hour intervals. Micrococcus varians grew in the two culture media studied, which confirms the experimental medium viability for the growth of this species. The final average concentration of biomass was higher in the control medium than in the experimental medium: 0.99 g.1-1 and 0.78 g.1-1, respectively. The final number of viable cells at the end of fermentation was 20.65 log10 CFU/ml for the control medium (BHI), while in the experimental medium the number of viable cells was 19.43 log10 CFU/ml. The consumption of total sugars was higher for the biomass in the control medium (79,78 per cent), while only 50.53(per cent) was consumed for the experimental medium.

Growth of Pediococcus acidilactici on sugar cane blackstrap molasses

Pediococcus acidilactici (IL01) has grown in MRS (Man, Rogosa and Sharpe) broth modified by substitution of glucose by 2.0(per cent) (MRS-2), 3.0(per cent) (MRS-3), 4.0(per cent) (MRS-4) and 5.0 (per cent) (MRS-5) sugar cane blackstrap molasses. The highest acid production was obtained in MRS-5 broth maintained at a constant pH of 5.0. The higest biomass production was obtained when P. acilactici was grown in MRS-5 broth at initial pH6.5, while productivity was higher in MRS-2 broth (28.16per cent). When the MRS-2broth was utilized at initial pH 6.5 for a 20-hour fermentation period, the highest growth rate (dx/dt) was found in a period of 8 to 16 hours (0.290 g cells/L.h), while the specific growth rate (µ) was 0.175 (h-1) for that period, differently from the 0,441 (h-1) obtained for the period comprising the 4th to the 12th hour. The growth in MRS broth was 5.08(per cent) (2.95g/1) higher than in MRS-2 broth (2.80 g/1). The data obtained have shown that P. acidilactici has had a significant growth in molasses as the main carbon source, and that it is possible to substitute MRS glucose by this carbon source with the purpose of obtaining a more economical growth medium for the potential large scale productions.