Carotenoid bioaccessibility from nine raw carotenoid-storing fruits and vegetables using an in vitro model

BACKGROUND: Many techniques exist for processing fruits and vegetables. The impact of these processes on nutritional qualities of the food can be considerable, however. Given the benefits of eating raw foods, nutrient sources need to be identified that deliver substantial benefit without cooking. In this study a survey of carotenoid bioaccessibility was carried out in order to additionally evaluate the impact of their distinctive storage structures (chromoplasts) on bioaccessibility. RESULTS: Per cent carotenoid bioaccessibility varied among the nine raw, whole fruits and vegetables evaluated, with values of 1–39% for lycopene, 18–20% for α‐carotene, 7–49% for β‐carotene, 9–59% for lutein, 4–22% for violaxanthin and 47–96% for phytoene. Per 100 g of food, grapefruit and watermelon imparted the most lycopene (69 and 64 µg respectively), carrot the most α‐carotene (559 µg), β‐carotene (1078 µg), lutein (91 µg) and phytoene (23 mg) and mango the most violaxanthin (177 µg). Digestive stability averaged over 80%, except for the xanthophylls, which exhibited a wider and lower range of stabilities. CONCLUSION: These data identify raw food sources for carotenoid bioaccessibilities comparable to those of other foods accomplished by substantial processing. The information presented here also has application in identifying appropriate plant‐breeding goals and optimal sources for commercial carotenoid isolations. Copyright © 2012 Society of Chemical Industry     

Prevalence and typing of Listeria monocytogenes in ready-to-eat food products on the Belgian market

Listeria monocytogenes is a major concern to producers of ready-to-eat foods because of the high mortality rate associated with listeriosis and the widespread nature of the organism. To investigate the prevalence of this pathogen in different ready-to-eat food products on the Belgian market, a variety of 252 ready-to-eat food products, mainly fish and meat products, were analyzed. Overall, L. monocytogenes was detected in 23.4% of the samples. The highest prevalence of L. monocytogenes was found in prepared minced meat (42.1%) and smoked halibut (33.3%). Contamination levels were in most cases low (<10 CFU/g); however, levels higher than 100 CFU/g were detected in some samples of smoked salmon, smoked halibut, and prepared minced meat. A high prevalence of Listeria innocua (15.8%) and Listeria welshimeri (36.8%) was detected in prepared minced meat. L. monocytogenes strains isolated from different contaminated products were subjected to repetitive element sequence-based PCR (REP-PCR) typing to determine possible associations with product type, producer, or market. REP-PCR patterns were analyzed using BioNumerics software, and seven different groups with at least 90% similarity were identified. The cluster analysis indicates that cross-contamination occurred at the producer and retail level. Serotype identification of the strains by PCR revealed that most belonged to the 1/2a(3a) serotype group.     

The role of extracellular polymeric substances in the toxicity response of activated sludge bacteria to chemical toxins

The objective of this study was to evaluate the respiration inhibition induced by octanol, cadmium, N-ethylmaleimide (NEM) and cyanide on activated sludge biomasses with different floc structures but similar physiological characteristics. Mechanical shearing was applied to fresh mixed liquor to produce biomasses with different floc structure properties. Specific oxygen uptake rate assays were conducted on the sheared and unsheared mixed liquors. The results showed that mechanical shearing resulted in release of biopolymers from the floc extracellular polymeric substances (EPS) matrix into the bulk liquid and a simultaneous reduction in floc size. Shearing did not impact biomass viability. The respiration inhibition by octanol and cadmium was more severe in sheared mixed liquor than in the unsheared biomass. Conversely, the respiration inhibition induced by NEM and cyanide was similar for the different mixed liquors tested. We conclude that the EPS matrix functions as a protective barrier for the bacteria inside activated sludge flocs to chemicals that it has the potential to interact with, such as hydrophobic (octanol) and positively charged (cadmium) compounds, but that the toxicity response for soluble, hydrophilic toxins (NEM and cyanide) is not influenced by the presence of the polymer matrix.     

Degradation of the antibiotic oxolinic acid by photocatalysis with TiO2 in suspension

In the work presented here, a photocatalytic system using titanium Degussa P-25 in suspension was used to evaluate the degradation of 20 mg L⁻¹ of antibiotic oxolinic acid (OA). The effects of catalyst load (0.2-1.5 g L⁻¹) and pH (7.5-11) were evaluated and optimized using the surface response methodology and the Pareto diagram. In the range of variables studied, low pH values and 1.0 g L⁻¹ of TiO₂ favoured the efficiency of the process. Under optimal conditions the evolution of the substrate, chemical oxygen demand, dissolved organic carbon, toxicity and antimicrobial activity on Escherichia coli cultures were evaluated. The results indicate that, under optimal conditions, after 30 min, the TiO₂ photocatalytic system is able to eliminate both the substrate and the antimicrobial activity, and to reduce the toxicity of the solution by 60%. However, at the same time, ∼53% of both initial DOC and COD remain in solution. Thus, the photocatalytical system is able to transform the target compound into more oxidized by-products without antimicrobial activity and with a low toxicity. The study of OA by-products using liquid chromatography coupled with mass spectrometry, as well as the evaluation of OA degradation in acetonitrile media as solvent or in the presence of isopropanol and iodide suggest that the reaction is initiated by the photo-Kolbe reaction. Adsorption isotherm experiments in the dark indicated that under pH 7.5, adsorption corresponded to the Langmuir adsorption model, indicating the dependence of the reaction on an initial adsorption step.     

Way finding during fire evacuation; an analysis of unannounced fire drills in a hotel at night

Findings in earlier studies on fire evacuation and way finding suggest that building features have influence on evacuation behaviour. For example, way finding is believed to be strongly dependent on the lay-out of the building and seems to be hardly dependent on (escape) route signs. Though some aspects are investigated, it is not discussed at great length. In particular there is little insight in how persons find their escape route, and how this process can be supported with lay-out and design measures has been hardly examined. Thus, there is need for insight in the decision-making processes which evacuees pass through. In this paper are the results presented of 83 evacuation experiments in a hotel building at night. The main focus of the study is on way finding during fire evacuation. In the evacuation experiments we investigated the possible influence of smoke and low placed exit signs on the human fire response performance. The experiments are carried out with a traditional research method, namely the registration and evaluation of unannounced fire drills. The study is conducted as part of the validation of a new research method that makes use of serious gaming. The results of the study suggest that smoke has influence on the route choice: when no smoke is perceptible the majority of the participants escape via the main exit and when smoke blocks the route towards the main exit, the majority of the participants escape via the fire exit. Furthermore, low placed exit signs appear to have a positive influence on the use of the nearest fire exit. The personal feature of prior knowledge of the surroundings (or type of surroundings) is also found to have a positive influence on the use of the nearest fire exit. Self-assessments and interviews after a fire evacuation are found to be a disputable method for research on human behaviour in fire. A real-time observation of the people's behaviour during evacuation is considered to give more reliable results.     

Far-field photostable optical nanoscopy (PHOTON) for real-time super-resolution single-molecular imaging of signaling pathways of single live cells

Cellular signaling pathways play crucial roles in cellular functions and design of effective therapies. Unfortunately, study of cellular signaling pathways remains formidably challenging because sophisticated cascades are involved, and a few molecules are sufficient to trigger signaling responses of a single cell. Here we report the development of far-field photostable-optical-nanoscopy (PHOTON) with photostable single-molecule-nanoparticle-optical-biosensors (SMNOBS) for mapping dynamic cascades of apoptotic signaling pathways of single live cells in real-time at single-molecule (SM) and nanometer (nm) resolutions. We have quantitatively imaged single ligand molecules (tumor necrosis factor α, TNFα) and their binding kinetics with their receptors (TNFR1) on single live cells; tracked formation and internalization of their clusters and their initiation of intracellular signaling pathways in real-time; and studied apoptotic signaling dynamics and mechanisms of single live cells with sufficient temporal and spatial resolutions. This study provides new insights into complex real-time dynamic cascades and molecular mechanisms of apoptotic signaling pathways of single live cells. PHOTON provides superior imaging and sensing capabilities and SMNOBS offer unrivaled biocompatibility and photostability, which enable probing of signaling pathways of single live cells in real-time at SM and nm resolutions.