Food production in four school kitchens was checked in order to improve food safety by establishing a self-regulated control system based on good manufacturing practices (GMPs) and as an introduction to hazard analysis and critical control points (HACCP). A form, which referred to different aspects such as the cleanliness of the installations, personnel hygiene and the prevention of cross-contamination, was used to obtain the necessary data. Furthermore, foods thought to be of high risk were periodically collected for microbiological analysis. Samples for microbiological examination were taken from cutting boards, tables, machines, knives and ingredients (on-line sampling). We used the results as a basis to train foodhandlers to improve the safety of salad preparation, in accordance with GMPs, observing that hygiene improvement depended on chlorine levels in the rinsing water. We also designed several controls for raw materials, cold storage, freezers and available chlorine levels in water. At the end of the study period, we observed a decrease in microbial populations of examined samples, which indicated that the knowledge of hygiene practices on the part of foodhandlers represents a critical control point, as defined by the EC Directive 93/43/EEC on Hygiene of Food Stuffs. 相似文献
Development research has been carried out in order to solve a practical industrial problem: to counteract axial displacement (axial drift or axial creep) of workpieces during the welding process. Solutions found in the literature generally provide adequate results; however, they are mechanically complex with high purchase and maintenance costs. A mechanically simple and inexpensive solution is proposed in this paper. Axial drift is measured with a low-cost custom-built contact displacement sensor. This sensor can measure axial drift without calibration or set-up operations. It is highly robust in order to function correctly in industrial conditions. A pneumatic cylinder moves the idle turning roll along a rail, modifying the longitudinal position of the idle turning roll in order to counteract axial drift. The position of the idle turning roll is controlled by a control algorithm, which consists of a set of rules. Tests were carried out in order to validate the proposed solution, which can be applied to existing turning rolls thereby significantly reducing costs. 相似文献
Thin films of the semiconductor NiO are deposited using a straightforward combination of simple and versatile techniques: the co-precipitation in aqueous media along with the dip- coating process. The obtained material is characterized by gravimetric/differential thermal analysis (TG–DTA) and X-ray diffraction technique. TG curve shows 30 % of total mass loss, whereas DTA indicates the formation of the NiO phase about 578 K (305 °C). X-ray diffraction (XRD) data confirms the FCC crystalline phase of NiO, whose crystallinity increases with thermal annealing temperature. UV–Vis optical absorption measurements are carried out for films deposited on quartz substrate in order to avoid the masking of bandgap evaluation by substrate spectra overlapping. The evaluated bandgap is about 3.0 eV. Current–voltage (I–V) curves measured for different temperatures as well as the temperature-dependent resistivity data show typical semiconductor behavior with the resistivity increasing with the decreasing of temperature. The Arrhenius plot reveals a level 233 meV above the conduction band top, which was attributed to Ni2+ vacancy level, responsible for the p-type electrical nature of NiO, even in undoped samples. Light irradiation on the films leads to a remarkable behavior, because above bandgap light induced a resistivity increase, despite the electron–hole generation. This performance was associated with excitation of the Ni2+ vacancy level, due to the proximity between energy levels. 相似文献
Lettuce is highly appreciated for its nutritional properties; however microbial contamination through the food chain and its raw consumption may jeopardize these known benefits to the diet. The objective of this study was to determine the role of the consumer at the stage of washing at home, in relation to the probability of illness due to the presence of Listeria monocytogenes in lettuce. Survival curves of L. monocytogenes after washing (dipping with and without addition of bleach, and washing under a running tap) were studied. A mathematical model for each washing method was calculated by fitting experimental data. The obtained models were used to estimate the probability of illness after washing at home. Results show that although consumers can only deal with low loads of L. monocytogenes, their role is essential to reduce the normal contamination level of lettuces and ensure their safety. 相似文献
The human alpha‐Synuclein (αS) protein is of significant interest because of its association with Parkinson's disease and related neurodegenerative disorders. The intrinsically disordered protein (140 amino acids) is characterized by the absence of a well‐defined structure in solution. It displays remarkable conformational flexibility upon macromolecular interactions, and can associate with mitochondrial membranes. Site‐directed spin‐labeling in combination with electron paramagnetic resonance spectroscopy enabled us to study the local binding properties of αS on artificial membranes (mimicking the inner and outer mitochondrial membranes), and to evaluate the importance of cardiolipin in this interaction. With pulsed, twofrequency, double‐electron electron paramagnetic resonance (DEER) approaches, we examined, to the best of our knowledge for the first time, the conformation of αS bound to isolated mitochondria. 相似文献
Existing buildings constitute a large portion of the UK’s housing stock. Refurbishment of existing buildings can, therefore, have an important role in achieving the UK government’s CO2 reduction targets. While building regulations and rating frameworks mainly focus on the improvements of the operational performance of buildings, Life Cycle Analysis is considered to be a more appropriate framework to account for long–term CO2 savings. This study evaluates a range of retrofit approaches (simple, medium, and deep), in terms of Life Cycle Carbon Footprint applied on a terraced house—one of the most common housing archetypes in London. The initial state of the original building has also been examined assuming three initial states (never refurbished, refurbished in compliance with the 1976 and with the 2000 building regulations). Results showed that for all initial state scenarios, deep retrofit achieved the lowest life cycle carbon emissions, in absolute figures, compared to the simple and medium retrofits. Simple retrofit packages, on the other hand, achieved quick and significant improvements, especially in buildings with poor initial thermal conditions. The study also indicated that retrofit packages applied on highly efficient building fabrics result in longer carbon payback time periods. The study recommends establishing a ‘staggered’ retrofitting approach, which pushes for ‘older building first’ and ‘simple retrofit packages first’, as these gain quick CO2 savings. Deep retrofit packages and treatment of relatively new buildings should be implemented at a later stage, to push buildings further to Zero–Carbon target.