RESUMO A qualidade dos produtos derivados de ovos depende da qualidade da matéria-prima e da produção industrial. A contaminação por fungos e bactérias pode ocorrer após a exposição do produto no mercado varejista. O objetivo deste estudo foi avaliar a qualidade microbiológica de 60 amostras de derivados de ovos e avaliar os efeitos da radiação gama de cobalto-60, utilizando-se as doses de 5 e 10 kGy, para descontaminação dos produtos coletados no mercado varejista da cidade de São Paulo. A contagem bacteriana foi realizada pelo número mais provável (MPN), e as contagens fúngicas por diluição seriada em plaqueamento de superfície. Foi observada uma diminuição dos valores da umidade e da atividade de água (Aa) das amostras irradiadas de ovo integral em pó e clara em pó (p<0,05), mas sem alteração significativa do pH nas mesmas amostras irradiadas com 5 e 10 kGy (p>0,05). Em gema em pó, observou-se diferença significativa (p<0,05) nos valores de pH e Aa, mas não houve mudança expressiva nos valores de umidade nas amostras irradiadas com 5 e 10 kGy (p>0,05). A esterilização microbiana eficaz de todos os produtos ocorreu com a dose de 10 kGy.

ABSTRACT The quality of products derived from eggs depends on the quality of the raw material source and the industrial production. The contamination by fungi and bacteria can occur after exposure of the product in the retail market. The objective of this study was to evaluate the microbiological quality of 60 samples of derivated egg products and evaluate the effects of gamma radiation of cobalt-60, using the dose of 5 and 10 kGy, for decontamination of products collected in the retail market in the São Paulo city. The bacterial count was performed by the most probable number (MPN) and the fungal counts by serial dilution after plating surface. It was observed a decrease in the humidity and water activity (Aw) values of irradiated whole egg powder and white egg powder samples (p<0.05), but there was no significant change in the pH of the same samples irradiated with 5 and 10 kGy (p>0.05). In the powdered yolk the values of pH and Aw presented a significant difference (p<0.05), but no significant difference in the humidity values of 5 and 10 kGy irradiated samples (p>0.05). Effective microbial sterilization of all products occurred at the dose of 10 kGy.

Abstract This work investigated the anaerobic degradation of the model azo dye Remazol Yellow Gold RNL in batch reactors using discharged residual yeast as the source of redox mediators (RM). Two yeast lysis methods (mechanical lysis and sonication) were tested and optimized to produce a riboflavin-rich yeast lysate. The reactors were operated at 25 ºC for 48 hours, evaluating the effect of external carbon source (glucose) and RM (from residual yeast lysate and commercial yeast extract) addition. The results showed that color removal efficiencies for the batch reactors fed with commercial yeast extract reached 90%, whereas those fed with discharged yeast lysate reached 80% (sonication) and 73% (mechanical lysis). These values were statistically higher when compared to reactors operating without RM (48 to 66%), demonstrating that yeast extract enhances azo dye degradation in anaerobic conditions and that the residual yeast is a cheap and alternative source of carbon and of the RM riboflavin.

Abstract This paper evaluated the treatment of textile wastewater in submerged anaerobic membrane bioreactors (SAMBR) operated on a bench scale. Particularly, the influence of operational conditions, such as the applied organic rate (OLR) and the dilution factor (for toxicity attenuation) of the textile wastewater, was evaluated on color and organic matter removal. In addition, the effect of powdered activated carbon (PAC) on SAMBR-1 and the addition of yeast extract (source of the redox mediator riboflavin) were also investigated. The results showed that reducing the textile wastewater dilution factor from 10× (phase 1) to 4× (phase 2) and 0× (no dilution) decreased the COD and color removal efficiencies in both SAMBRs, probably due to an increase in the toxic load. Nevertheless, PAC adsorbed toxic compounds found in the textile wastewater and helped biomass acclimatization, which led to higher COD and color removal efficiencies in SAMBR-1. The presence of yeast extract enhanced color removal efficiencies 3-fold in both SAMBRs when they were fed with undiluted textile wastewater.

Abstract This paper presents an assessment of ozone oxidative effects on the biodegradability of sugar cane vinasse, aiming at increasing the methane yield by anaerobic digestion of this effluent. Furthermore, as a new approach, an economic balance of this process was made. Using a bench scale reactor, ozone was applied at 60, 120, 180, 240 mgO3.gCOD-1 doses in raw vinasse and at three initial pH values (4.8, 7 and 9). Applying 60 mgO3.gCOD-1, the biodegradability of vinasse was increased by 22.7% at the initial pH value of 4.8. The application of the two-way ANOVA test indicated a significant statistical interaction between the pH value and ozone. However, a preliminary energy assessment showed that the amount of electricity consumed in a full-scale ozonation plant would be almost 6 times higher than the energy recovered from the combustion of the additional methane produced (13.6%). These results indicate that ozonation of raw vinasse to increase the methane production in a subsequent anaerobic process is economically unfeasible.

AbstractThis paper investigates the simultaneous removal of arsenic [As(V) or As(III)] and manganese [Mn(II)] from natural waters of low and high turbidity by clarification (with polyaluminum chloride and aluminum sulfate as primary coagulants) associated or not with chlorine pre-oxidation. The results showed that the clarification process exhibited low Mn(II) removal, that varied from 6% to 18% and from 19% to 27% for natural waters of low and high turbidity, respectively. The use of chlorine as pre-oxidant increased Mn(II) removal up to 77% and was associated with the formation of birnessite. Regarding As(V) removal by clarification, particularly for high turbidity water, a concentration lower than that established by the National Drinking Water Quality Standards (10 μg.L-1) was achieved in almost all tests. Oxidation preceding the clarification led to AsIII removal efficiencies from 80% to 90% for both coagulants and types of water.

Abstract Reactor hydrodynamics is important for sulfidogenesis because sulfate reduction bacteria (SRB) do not granulate easily. In this work, the sulfate reduction performance of two continuous anaerobic bioreactors was investigated: (i) an upflow anaerobic sludge blanket (UASB) reactor and (ii) a fluidized bed reactor (FBR). Organic loading, sulfate reduction, and COD removal were the main parameters monitored during lactate and glycerol degradation. The UASB reactor with biomass recirculation showed a specific sulfate reduction rate of 0.089±0.014 g.gSSV-1.d-1 (89% reduction), whereas values twice as high were achieved in the FBR treating either lactate (0.200±0.017 g.gSSV-1.d-1) or glycerol (0.178±0.010 g.gSSV-1.d-1). Sulfate reduction with pure glycerol produced a smaller residual COD (1700 mg.L-1) than that produced with lactate (2500 mg.L-1) at the same COD.sulfate-1 mass ratio. It was estimated that 50% of glycerol degradation was due to sulfate reduction and 50% to fermentation, which was supported by the presence of butyrate in the FBR effluent. The UASB reactor was unable to produce effluents with sulfate concentrations below 250 mg.L-1 due to poor mixing conditions, whereas the FBR consistently ensured residual sulfate concentrations below such a value.

This paper presents data for the synthesis and characterization of layer double hydroxides (LDH) and their use for color and chemical oxygen demand (COD) removal from effluents generated by a textile industry. Adsorption studies with raw and biologically treated (activated sludge) textile effluent showed that the pseudo-second order model best fitted the experimental data, leading to adsorption coefficients of 39.1 and 102.9 mgCOD/gLDH for raw and treated effluents, respectively. The best conditions for color and COD removal were obtained at lower values of temperature and pH (25 °C and pH 7) and, in these conditions, an LDH dose of 10 g/L resulted in color removal efficiencies of 56% for samples of raw and 66% for samples of treated effluent. Recycling studies indicated that the reuse of thermally treated LDH led to a progressive loss in the removal efficiencies of COD and color. The reduction was more pronounced with samples of the raw textile effluent. LDH characterization performed before and after each adsorption and regeneration experiment showed that there was no intercalation of dye molecules in the interlayer region of the LDH, indicating that COD and color removal might be due to the adsorption of organic molecules onto the LDH surface.

Insetos podem infestar sementes e grãos que integram as rações destinadas à alimentação de pequenos roedores e aves domésticas como amendoim, girassol, trigo, milho, aveia e outros. Fungos toxigênicos (Aspergillus, Penicillium e Fusarium) também são contaminantes destes substratos e podem ser carreados por insetos. A deterioração da massa de sementes e grãos pela atividade dos insetos associado à presença de umidade, pode ser um facilitador para o crescimento fúngico e produção de micotoxinas. O objetivo do estudo foi o de analisar a micobiota associada às sementes, grãos e insetos em ração mista para animais domésticos. Vinte amostras foram plaqueadas em ágar-batata-dextrose incubadas a 25º C durante 7 dias para o isolamento fúngico de ração e em insetos isolados de cada componente da ração. Todas as amostras apresentaram presença de fungos e Sitophilus zeamais, inseto predominante e com maior frequencia nas amostras coletadas, demonstrando ser um vetor de vários gêneros fúngicos. Rações animais compostas de misturas de sementes e grãos estão sujeitas à contaminação microbiológica, sendo os insetos importantes vetores mecânicos de fungos deteriorantes e toxigênicos, comprometendo a saúde animal.

Insects invade stored foods such as corn, nuts and dried fruits that are ingredients of pet food. Toxigenic fungi (Aspergillus, Penicillium and Fusarium) are also contaminants of these substrates. The insects are mechanical vectors and the infestation increases the humidity of dried food, thus promoting the fungal growth and the production of mycotoxins. The objective of this study was to analyze the mycobiota associated with insect infestation found in pet foods. Twenty samples were plated on potato agar incubated at 25º C during 7 days, for the isolation of fungi from pet food and from insects isolated from each ingredient. The insects were identified by using a dichotomous key. All samples showed fungal presence, and Sitophilus zeamais was the predominant insect with the highest frequency in the collected samples, indicating it as a vector of many fungal genera. Pet foodscomposed by a mixture of seeds and grains are subject to microbial contamination, and the insects are important mechanical vectors of spoilage and toxigenic fungi, endangering animal health.

This work presents results on the production and characterization (by both mass spectrometry and conventional chemical analyses) of Soluble Microbial Products (SMP) that accumulated in aerobic and anaerobic bench scale completely stirred tank reactors (CSTRs) fed with glucose or acetate under different hydraulic retention times (HRT) and temperatures. SMP accumulation varied from 2 to 68% of the influent COD in the aerobic reactor and from 9 to 27% in the anaerobic reactor and increased with the decrease in temperature and with the HRT reduction in the aerobic reactor. On the other hand, in the anaerobic reactor, the organic loading rate and the temperature had little impact on SMP production, implying that the SMP originated from different mechanisms in each system. For both reactors, a higher accumulation of SMPs was observed as the substrate was acetate when compared to glucose, and the chemical analysis showed that the majority of the SMP did not seem to be proteins or carbohydrates. Principal component analysis (PCA) of the mass spectra from positive and negative mode electron-spray ionization (LC-IT-TOF-MS) and results from matrix assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF-MS) confirmed the chemical analyses and showed the absence of proteins in the effluents and the predominance of low molecular weight SMP. The PCA analysis also showed that the majority of the SMP from aerobic and anaerobic reactors did not seem to originate from soluble extracellular polymeric substances (EPS) or cell lysis products.

In this paper, we present a reactive location routing algorithm with cluster-based flooding for inter-vehicle communication. We consider a motorway environment with associated high mobility and compare position-based and non-position-based routing strategies, along with a limiting function for flooding mechanisms in reactive ad-hoc protocols. The performance of Dynamic Source Routing (DSR) and Ad-Hoc On-demand Distance Vector Routing (AODV) for non-positional and Location Routing Algorithm with Cluster-Based Flooding (LORA_CBF) for positional algorithms is considered. First, for small-scale networks, our research validates our proposed simulation model with the results of a test bed and the results of mathematical analysis. Then, for large-scale networks, we use simulations to compare our model with both the AODV and DSR reactive routing algorithms. Finally, we use a microscopic traffic model, developed in OPNET, to ascertain the mobility of 250 vehicles on a motorway with regards to average Route Discovery (RD) time, End-to-End Delay (EED), Routing Load, Routing Overhead, Overhead, and Delivery Ratio.

En este trabajo, presentamos un algoritmo de enrutamiento reactivo por posición basado en grupos para comunicación Inter.-vehicular. También se ha estimado un escenario automovilístico de alta velocidad (autopista), y se ha comparado estrategias de enrutamiento reactivas basadas en posición y no-posición, además de un mecanismo de reducción de diseminación de información en protocolos ad-hoc reactivos. El rendimiento de los algoritmos basados en no-posición: Dynamic Source Routing (DSR) y Ad-Hoc On-Demand Distance Vector (AODV) y del algoritmo basado en posición: Location Routing Algorithm with Cluster-Based Flooding (LORA_CBF), han sido considerados. Como primer paso, hemos validado nuestro modelo de simulación propuesto en redes de pequeña escala, con los resultados de un experimento y los resultados de análisis matemático. Después, hemos usado simulaciones para comparar y validar nuestro modelo en redes de gran escala, con dos prominentes algoritmos reactivos: AODV y DSR. Finalmente, hemos desarrollado en OPNET, un modelo de trafico microscópico, que nos permite evaluar el rendimiento de 250 vehículos en términos del tiempo de descubrimiento de ruta, retardo punto a punto, carga de enrutamiento, sobre encabezado de enrutamiento, el sobre encabezado general y la razón de entrega de información.