BIFIDOBACTÉRIAS: ISOLAMENTO, IDENTIFICAÇÃO E APLICAÇÃO EM ALIMENTOS PROBIÓTICOS

This review aimed to describe the main culture media that have been developed for the isolation and enumeration of bifidobacteria and the molecular methods used for identification of this genus and its species. The criteria for probiotic bifidobacteria selection for their technological application were also demons trated (as tolerance to low pH, presence of oxygen and presence of ingredients and additives). Various studies carried out using a bifidobacteria in the development of probiotic foods were cited. It can be concluded that the constant consumer’s search for balance of health tends to increase the market for probiotic foods, stimulating research in the discovery of new strains with this activity and diversification of products.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 oxigênio 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 microrganismos 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

Aeromonas spp. isoladas de ostras (Crassostrea rhizophorea) coletadas em um criadouro natural, Ceará, Brazil

Between April and October 2002, thirty fortnightly collections of oysters (Crassostrea rhizophorea) from a natural oyster bed at the Cocó River estuary in the Sabiaguaba region (Fortaleza, Ceará, Brazil) were carried out, aiming to isolate Aeromonas spp. strains. Oyster samples were submitted to the direct plating (DP) and the presence/absence (P/A) methods. Aeromonas were identified in 15 (50%) samples analyzed by the DP method and in 13 (43%) analyzed by the P/A method. A. caviae, A. eucrenophila, A. media, A. sobria, A. trota, A. veronii bv. sobria, A. veronii bv. veronii and Aeromonas sp. were isolated. The predominant species was A. veronii (both biovars), which was identified in 13 (43%) samples, followed by A. media in 11 (37%) and A. caviae in seven (23%). From the 59 strains identified, 28 (48%) presented resistance to at least one of the eight antibiotics tested.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

Viability of a Five-Strain Mixture of Listeria monocytogenes in Vacuum-Sealed Packages of Frankfurters, Commercially Prepared with and without 2.0 or 3.0% Added Potassium Lactate, during Extended Storage at 4 and 10° C†‡

The viability of Listeria monocytogenes was monitored on frankfurters containing added potassium lactate that were obtained directly from a commercial manufacturer. Eight links (ca. 56 g each) were transferred aseptically from the original vacuum-sealed bulk packages into nylon-polyethylene bags. Each bag then received a 4-ml portion of a five-strain mixture of the pathogen. Frankfurters containing 2.0 or 3.0% potassium lactate were evaluated using 20 CFU per package, and frankfurters containing 3.0% potassium lactate were evaluated using 500 CFU per package. The packages were vacuum-sealed and stored at 4 or 10°C for up to 90 or 60 days, respectively. During storage at 4°C, pathogen numbers remained at about 1.6 log10 CFU per package over 90 days in packages containing frankfurters with 2.0% potassium lactate that were inoculated with about 20 CFU. In packages containing frankfurters with 3.0% potassium lactate that were inoculated with about 20 CFU and stored at 4°C, pathogen numbers remained at about 1..