RESUMEN

In this work, we suggest a methodology to determine the impact parameter for neutral dysprosium emission lines from the characterization of the plasma generated by laser ablation in a sealed chamber filled with argon. The procedure is a combination of known consistent spectroscopic methods for plasma temperature determination, electron density, and species concentration. With an electron density of 3.1 × 1018 cm-3 and temperature close to 104 K, we estimated the impact electron parameter for nine spectral lines of the neutral dysprosium atom. The gaps in the impact parameter data in the literature, mainly for heavy elements, stress the importance of the proposed method.

RESUMEN

This work aimed the obtainment of a neutral atomic jet departing from a plume generated by laser ablation of copper targets. A pair of electrodes together with a transducer pressure sensor was used to study the ablated plume charge composition and also to measure the ion extraction from the plasma plume. The neutral beam was produced with this setup and the relative abundance of neutrals in the plasma was measured, it decreases from 30% to 8% when the laser fluence is varied from 20 J/cm(2) to 32 J/cm(2). The necessary voltage to completely remove the ions from the plume varied from 10 V to 230 V in the same fluence range. TOF analysis resulted in center of mass velocities between 3.4 and 4.6 km/s, longitudinal temperature in the range from 1 × 10(4) K to 2.4 × 10(4) K and a Mach number of M = 2.36, calculated using purely hydrodynamic expansion approximation.

RESUMEN

Control of Listeria monocytogenes in food processing facilities is a difficult issue because of the ability of this microorganism to form biofilms and adapt to adverse environmental conditions. Survival at high concentrations of sodium chloride and growth at refrigeration temperatures are two other important characteristics of L. monocytogenes isolates. The aim of this study was to compare the growth characteristics under stress conditions at different temperatures of L. monocytogenes serotypes responsible for the majority of clinical cases from different sources. Twenty-two L. monocytogenes isolates, 12 from clinical cases (8 serotype 4b and 4 serotype 1/2a) and 10 from food (6 serotype 4b and 4 serotype 1/2a), and an L. monocytogenes Scott A (serotype 4b) reference strain were analyzed for the ability to grow in brain heart infusion broth plus 1.9 M NaCl (11%) at 4, 10, and 25°C for 73, 42, and 15 days, respectively. The majority of L. monocytogenes strains was viable or even grew at 4°C and under the high osmotic conditions usually used to control pathogens in the food industry. At 10°C, most strains could adapt and grow; however, no significant difference (P > 0.05) was found for lag-phase duration, maximum growth rate, and maximum cell density. At 25°C, all strains were able to grow, and populations increased by up 5 log CFU/ml. Clinical strains had a significantly longer lag phase and lower maximum cell density (P < 0.05) than did food strains. Regarding virulence potential, no significant differences in hemolytic activity were found among serotypes; however, serotype 4b strains were more invasive in Caco-2 cells than were serotype 1/2a strains (P < 0.05). The global tendency of decreasing NaCl concentrations in processed foods for health reasons may facilitate L. monocytogenes survival and growth in these products. Therefore, food companies must consider additional microbial growth barriers to assure product safety.

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Listeriosis is a serious foodborne disease caused by Listeria monocytogenes, a pathogen often found in food processing plants. Poultry meat and its derivatives may harbor L. monocytogenes even if good manufacturing practices are implanted in abattoirs. Little information exists in Brazil on the frequency of L. monocytogenes contamination, even though the country is considered the top poultry meat exporter in the world. This study attempted to compare 2 exporters poultry facilities following same the standards but differing only in manual (plant M) or automatic (plant A) evisceration. Eight hundred fifty-one samples from food, food contact and non-food contact surfaces, water, and workers' hands were collected from cage to finished products over a 1-yr period. In plant A, 20.1% of the samples were positive for L. monocytogenes, whereas in plant M, 16.4% was found. The greatest incidence of contamination with the pathogen in plant A was found in non-food contact surfaces (27.3%), while in plant M, it was found in products (19.4%). The most prevalent serovars were 1/2a or 3a (plant M) and 4b, 4d, or 4e (plant A). Despite having proper hygiene and good manufacturing practices, controlling the entry and persistence of L. monocytogenes in processing facilities remains a formidable task.

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L. monocytogenes is a foodborne psychrotrophic bacterial pathogen of special importance for minimally processed foods. In this work, it was enumerated in samples of surubim fish by MPN technique. The population of L. monocytogenes was estimated as < 0.012 MPN/cm² in fresh and < 0.03 MPN/g in minimally processed fish.

L. monocytogenes é um patógeno psicrotrófico transmitido por alimentos, de importância especial para alimentos minimamente processados. Neste trabalho, a bactéria foi enumerada em amostras de peixe surubim utilizando-se a técnica do NMP. A população de L. monocytogenes foi estimada como < 0.012 NMP/cm² do peixe fresco e < 0.03 NMP/g do peixe minimamente processado.

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RESUMEN

Listeria monocytogenes is a cause of concern to food industries, mainly for those producing ready-to-eat (RTE) products. This microorganism can survive processing steps such as curing and cold smoking and is capable of growing under refrigeration temperatures. Its presence in RTE fish products with extended shelf life may be a risk to the susceptible population. One example of such a product is gravlax salmon; a refrigerated fish product not exposed to listericidal processes and was the subject of this study. In order to evaluate the incidence and dissemination of L. monocytogenes 415 samples were collected at different steps of a gravlax salmon processing line in São Paulo state, Brazil. L. monocytogenes was confirmed in salmon samples (41 percent), food contact surfaces (32 percent), non-food contact surfaces (43 percent) and of food handlers' samples (34 percent), but could not be detected in any ingredient. 179 L. monocytogenes isolates randomly selected were serogrouped and typed by PFGE. Most of L. monocytogenes strains belonged to serogroup 1 (73 percent). 61 combined pulsotypes were found and a dendrogram identified six clusters: most of the strains (120) belonged to cluster A. It was suggested that strains arriving into the plant via raw material could establish themselves in the processing environment contaminating the final product. The wide dissemination of L. monocytogenes in this plant indicates that a great effort has to be taken to eliminate the microorganism from these premises, even though it was not observed multiplication of the microorganism in the final product stored at 4ºC up to 90 days.

Listeria monocytogenes é um patógenode grande preocupação para as indústrias alimentícias, principalmente aquelas produtoras de alimentos prontos para consumo (RTE). Este microrganismo pode sobreviver às etapas de cura e defumação a frio, além de tolerar temperaturas de refrigeração. A presença de L. monocytogenes em pescados RTE com vida de prateleira longa representa um risco para a população susceptível, sendo o salmão gravlax deste tipo de produto. No presente estudo avaliou-se a incidência e disseminação de L. monocytogenes em 415 amostras de salmão gravlax obtidas de diferentes etapas de processamento de uma indústria localizada no Estado de São Paulo. A presença de L. monocytogenes foi confirmada em amostras de salmão (41 por cento), superfícies de contato (32 por cento) e não contato (43 por cento) e manipuladores (34 por cento), porém não se isolou o microrganismo em nenhum ingrediente. Do total de cepas isoladas, 179 destas foram escolhidas aleatoriamente e submetidas a sorologia e tipagem por PFGE. A maioria dos isolados pertenceu ao sorogrupo 1 (73 por cento), sendo identificados 61 pulsotipos quando se combinou os resultados de sorologia e PFGE e 6 clusters foram distribuídos em um dendrograma. O cluster A agrupou a maioria das cepas (120). Pode-se sugerir que as cepas foram introduzidas na linha de processamento por meio da matéria prima e contaminando o produto final. Estes resultados indicam que a eliminação de L. monocytogenes deste estabelecimento requer um grande esforço, ainda que o microrganismo não se multiplicou no produto final estocado a 4ºC por 90 dias.

Asunto(s)

RESUMEN

Listeria monocytogenes is a cause of concern to food industries, mainly for those producing ready-to-eat (RTE) products. This microorganism can survive processing steps such as curing and cold smoking and is capable of growing under refrigeration temperatures. Its presence in RTE fish products with extended shelf life may be a risk to the susceptible population. One example of such a product is gravlax salmon; a refrigerated fish product not exposed to listericidal processes and was the subject of this study. In order to evaluate the incidence and dissemination of L. monocytogenes 415 samples were collected at different steps of a gravlax salmon processing line in São Paulo state, Brazil. L. monocytogenes was confirmed in salmon samples (41%), food contact surfaces (32%), non-food contact surfaces (43%) and of food handlers' samples (34%), but could not be detected in any ingredient. 179 L. monocytogenes isolates randomly selected were serogrouped and typed by PFGE. Most of L. monocytogenes strains belonged to serogroup 1 (73%). 61 combined pulsotypes were found and a dendrogram identified six clusters: most of the strains (120) belonged to cluster A. It was suggested that strains arriving into the plant via raw material could establish themselves in the processing environment contaminating the final product. The wide dissemination of L. monocytogenes in this plant indicates that a great effort has to be taken to eliminate the microorganism from these premises, even though it was not observed multiplication of the microorganism in the final product stored at 4°C up to 90 days.

RESUMEN

L. monocytogenes is a foodborne psychrotrophic bacterial pathogen of special importance for minimally processed foods. In this work, it was enumerated in samples of surubim fish by MPN technique. The population of L. monocytogenes was estimated as < 0.012 MPN/cm(2) in fresh and < 0.03 MPN/g in minimally processed fish.

RESUMEN

L. monocytogenes is a foodborne psychrotrophic bacterial pathogen of special importance for minimally processed foods. In this work, it was enumerated in samples of surubim fish by MPN technique. The population of L. monocytogenes was estimated as 0.012 MPN/cm² in fresh and 0.03 MPN/g in minimally processed fish.

L. monocytogenes é um patógeno psicrotrófico transmitido por alimentos, de importância especial para alimentos minimamente processados. Neste trabalho, a bactéria foi enumerada em amostras de peixe surubim utilizando-se a técnica do NMP. A população de L. monocytogenes foi estimada como 0.012 NMP/cm² do peixe fresco e 0.03 NMP/g do peixe minimamente processado.

RESUMEN

Listeria monocytogenes is a cause of concern to food industries, mainly for those producing ready-to-eat (RTE) products. This microorganism can survive processing steps such as curing and cold smoking and is capable of growing under refrigeration temperatures. Its presence in RTE fish products with extended shelf life may be a risk to the susceptible population. One example of such a product is gravlax salmon; a refrigerated fish product not exposed to listericidal processes and was the subject of this study. In order to evaluate the incidence and dissemination of L. monocytogenes 415 samples were collected at different steps of a gravlax salmon processing line in São Paulo state, Brazil. L. monocytogenes was confirmed in salmon samples (41%), food contact surfaces (32%), non-food contact surfaces (43%) and of food handlers' samples (34%), but could not be detected in any ingredient. 179 L. monocytogenes isolates randomly selected were serogrouped and typed by PFGE. Most of L. monocytogenes strains belonged to serogroup 1 (73%). 61 combined pulsotypes were found and a dendrogram identified six clusters: most of the strains (120) belonged to cluster A. It was suggested that strains arriving into the plant via raw material could establish themselves in the processing environment contaminating the final product. The wide dissemination of L. monocytogenes in this plant indicates that a great effort has to be taken to eliminate the microorganism from these premises, even though it was not observed multiplication of the microorganism in the final product stored at 4ºC up to 90 days.

Listeria monocytogenes é um patógenode grande preocupação para as indústrias alimentícias, principalmente aquelas produtoras de alimentos prontos para consumo (RTE). Este microrganismo pode sobreviver às etapas de cura e defumação a frio, além de tolerar temperaturas de refrigeração. A presença de L. monocytogenes em pescados RTE com vida de prateleira longa representa um risco para a população susceptível, sendo o salmão gravlax deste tipo de produto. No presente estudo avaliou-se a incidência e disseminação de L. monocytogenes em 415 amostras de salmão gravlax obtidas de diferentes etapas de processamento de uma indústria localizada no Estado de São Paulo. A presença de L. monocytogenes foi confirmada em amostras de salmão (41%), superfícies de contato (32%) e não contato (43%) e manipuladores (34%), porém não se isolou o microrganismo em nenhum ingrediente. Do total de cepas isoladas, 179 destas foram escolhidas aleatoriamente e submetidas a sorologia e tipagem por PFGE. A maioria dos isolados pertenceu ao sorogrupo 1 (73%), sendo identificados 61 pulsotipos quando se combinou os resultados de sorologia e PFGE e 6 clusters foram distribuídos em um dendrograma. O cluster A agrupou a maioria das cepas (120). Pode-se sugerir que as cepas foram introduzidas na linha de processamento por meio da matéria prima e contaminando o produto final. Estes resultados indicam que a eliminação de L. monocytogenes deste estabelecimento requer um grande esforço, ainda que o microrganismo não se multiplicou no produto final estocado a 4ºC por 90 dias.

RESUMEN

Cherubism is a rare hereditary fibro-osseous childhood disease characterized by bone degradation and fibrous tissue replacement at the angles of the mandible and at the tuberosity areas of the maxilla that leads to prominence of the lower face and an appearance reminiscent of the cherub's portrayal in Renaissance art. This disease has an autosomal dominant hereditary characteristic. The purpose of this report is to analyse laboratory tests, clinicopathological and radiographic features of cherubism and its intraoral manifestations in a patient during 4-years of follow-up, correlating the features observed in this case with those of the literature. Also discussed is the atypical and aggressive behaviour of this case during puberty.

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There is scarce information in Brazil and other South American countries about the occurrence of Listeria monocytogenes in food, mainly refrigerated ready-to-eat products. The consumption of sliced vacuum-packaged meat products has increased in the last few years. Nevertheless, a complete assessment of the risk associated with L. monocytogenes in these products is still necessary. Because of the production and storage characteristics of these products, they can be considered potential vehicles for L. monocytogenes to humans, mainly immunocompromised, elderly, and pregnant women. The objectives of this study was to evaluate the population of L. monocytogenes in salami, a ready-to-eat meat product with extended shelf life, acquired in retail stores in São Paulo-Brazil. The three-tube most probable number technique was used and the methodology was that from Health Canada. Strains were biochemically identified and serotyped. Among the 45 samples, 3 (6.7 per cent) harboured 9.2 MPN/g of L. monocytogenes and the others < 0.3 MPN/g. All the strains belonged to serotypes 1/2a and 1/2b, the most frequent serotypes found in food everywhere. Even being low, the population of L. monocytogenes found in this product could be a cause of concern to public health authorities as it can pose a threat to population at risk. This contamination highlights the importance of implementing systems like HACCP to assure safe products to consumers.

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This study measures the detection performances of two rapid test systems (Listeria Rapid Test Clearview and Bax system) for the screening of Listeria sp. and Listeria monocytogenes, respectively. A total of 413 samples from different sources (product from (i) different stages of processing, (ii) different environments, and (iii) different food handlers), collected from a chicken nugget processing plant, were analysed by both rapid methods and a cultural method consisting of pre-enrichment, enrichment, and isolation onto selective agars (PALCAM, LPM, and HCLA). Overall, results showed an excellent correlation between data obtained using Clearview and the cultural method, with Clearview presenting an efficiency of 99%. Bax showed a lower correlation using the cultural method, with an efficiency of 71.1%. The type of sample did not affect the efficiency of Clearview, which varied from 98.1% for product samples to 100% for environmental and food handler samples, while for Bax it had a marked influence. Efficiency of Bax varied from as high as 100% for food handlers to 37.9% for product samples.

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The detection and identification of Salmonella spp. is still troublesome and time consuming to the food industry. Employing the modified semi-solid Rappaport-Vassiliadis medium (MSRV), presumptive results for Salmonella can be obtained in 48 h, representing an interesting alternative to the standard methods. The specificity and sensitivity of the MSRV method were evaluated in this research. The efficiency of this method was also compared with the methodology recommended by the US Food and Drug Administration (FDA) using bismuth sulfite agar, XLT4 agar and Rambach agar. A total of 146 food samples comprised of 41 chicken thighs, 35 Brazilian fresh pork sausages, 35 samples of cocoa powder and/or granulated cocoa and 35 samples of grated fresh coconut, were examined. Overall, the rapid method (direct + indirect) and the standard culture detected 96.1% and 84.6% of the positive samples, respectively. No Salmonella was detected in the coconut or cocoa samples by any of the methods. Eighteen (43.9%) chicken thigh samples were contaminated with the microorganism. The rapid method (direct + indirect) and the standard culture detected 94.4% and 88.9% of these, respectively. Salmonella was detected in eight (22.8%) fresh pork sausage samples. The MSRV method detected Salmonella in all eight samples, while the standard gave positive results in six (75%). When compared with the standard method, the indirect method showed 86.4% sensitivity and 96.8% specificity, while the direct MSRV showed a sensitivity of 71.4% and specificity of 99.2%. Combined, both MSRV methods showed 95.5% sensitivity and 96.8% specificity. The MSRV medium also reduces the time necessary for the isolation of Salmonella from foods.

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A total of 207 L. monocytogenes strains isolated from different types of cheeses commercialized in the city of Rio de Janeiro, Brazil, were serotyped and evaluated for their ability to produce beta-haemolysin and lecithinase and to adsorb Congo red dye. Of the 207 strains, 59.9, 27.5 and 12.6% belonged to serotypes 1/2a, 1/2b and 4b, respectively. In addition, 175 strains of L. monocytogenes produced lecithinase while strains of the other species did not. Some of the non-L. monocytogenes strains adsorbed the dye Congo red, while some L. monocytogenes did not. Statistical analysis of the results showed significant differences (P < 0.05) amongst the virulence tests and the three serotypes found. In the present study, 32 L. monocytogenes strains were also analyzed by RAPD (randomly amplified polymorphic DNA). RAPD analysis allowed the discrimination among strains of different serotypes, as well as among strains of the same serotype. It is important to emphasize that the use of more than one primer is needed for characterization of L. monocytogenes strains. With RAPD the strains were grouped into six different profiles, some of them common for strains belonging to different serotypes. The results also indicated a close genetic relationship among strains of different serotypes.

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The presence of Listeria monocytogenes in ready-to-eat meat products is cause of concern to the food industry as well as to health authorities. Studies were conducted to evaluate the presence of L. monocytogenes in mortadellas acquired at retail stores and to evaluate the fate of two levels of a L. monocytogenes pool spiked in two different formulations of the product, cooked under commercial conditions and stored at refrigeration (7°C) and room temperature (25°C). Among the samples collected at different retail stores, 26.7% harboured L. monocytogenes. Regarding to the fate of L. monocytogenes in mortadella, periodically, samples were taken and the surviving L. monocytogenes cells in the spiked products were counted by the MPN procedure. Populations of <0.35 MPN/g of L. monocytogenes were found in these samples. It could be concluded that the heat treatment was effective to reduce 3-log of L. monocytogenes independent of formulation or storage conditions.

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The incidence of Salmonella spp., Listeria spp. and Listeria monocytogenes in horsemeat for human consumption was investigated. One-hundred and twenty-one samples of frozen horsemeat collected from two Brazilian abattoirs were analysed over a period of 1 year. Twenty-two samples (18.2%) were positive for Listeria spp. with nine (7.4%) containing L. monocytogenes. None of the samples harbored Salmonella spp.

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The incidence and importance of Listeria spp. in fish and fishery products in Latin American countries is reviewed. There are very few papers dealing with this subject, however it is known that Listeria can be an important problem even for fisheries of tropical countries. The importance of GMP and HACCP implementation is also discussed.

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We report a technique of auricular replantation used in a case of traumatic amputation. The principal difficulties encountered in this type of replantation are mentioned, and ways of avoiding them are suggested. All the skin of the ear was removed except for that of the anterior surface of the conch. At this site, the cartilage received small, multiple perforations to allow for nutrition of the corresponding skin. The remainder of the auricular cartilage was covered by a skin flap undermined from the mastoid region. Three months later, the retro-auricular region was freed and covered with a total skin graft taken from the right supraclavicular region. On the basis of the satisfactory results obtained, we discuss the intention and the technical details of the method and possible contraindications.

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The present study evaluated the incidence of Listeria spp. in raw and pasteurized milk from a Brazilian dairy plant. Ten samples of each type of milk (raw types B and C and pasteurized types B and C) were collected monthly from October 1989 to September 1990 (except in December), comprising 440 samples (110 samples of each type of milk). The recovery of Listeria spp. was carried out using LPM (lithium chloride phenylethanol moxalactam) and MOX (modified Oxford) agars, after a two-step enrichment procedure in Listeria enrichment broth (LEB) and Fraser broth. Overall, 12.7% of raw milk samples, 0.9% of pasteurized milk samples and 6.8% of total of milk samples were positive for Listeria spp., while 9.5% of raw milk samples, none of the pasteurized milk samples and 4.8% of total milk samples, were positive for Listeria monocytogenes. Raw milk also contained L. innocua (9.5%), L. welshimeri (0.9%) and L. grayi (0.4%). Pasteurized milk contained only L. innocua (0.9%).

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