Influence of temperature on conservability of chilled vacuum packed beef from different origins

peer reviewedaudience: researcher, professionalThe objective of this experiment was to study the conservability of chilled vacuum-packed meat depending on storage temperature (–1 °C vs. +4 °C) during the last third of their shelf life. Physicochemical parameters (pH and colour) and microbiological growth (total aerobic bacteria, lactic acid bacteria, Enterobacteriaceae, Pseudomonas spp. and Brochothrix thermosphacta) of Longissimus dorsi samples from different origins (United Kingdom and Ireland, Australia and Brazil) were measured at: i) 2/3 of their shelf life and ii) the end of their shelf life. Sample bacteria population growing on MRS was identified by API 50 CHL strips. Unlike Irish and British samples, pH of some Australian and Brazilian samples decreased during conservation. The colour of the samples remained stable and it did not seem to be influenced by temperature. All samples conserved at –1 °C presented a satisfactory microbiological quality at the end of their shelf life (British and Irish meat = 35~45 days; Australian meat = 140 days and Brazilian meat = 120 days). On Australian and Brazilian samples, temperature did not influence total aerobic bacteria growth, but conservation at +4 °C favoured lactic acid bacteria and Enterobacteriaceae growth. API 50 CHL strip identifications revealed the presence of bacteria like Lactobacillus brevis, Carnobacterium maltaromaticum and Lactobacillus fermentum, which occur naturally in fresh meat and are known for their bioprotective effect against other microorganisms. Further analyses are being carried out using molecular methods in order to study the initial bacteria population diversity and it evolution during storage.CONSBBB - Conservation longue durée de la viande fraîche de bovins Blanc-Bleu Belge : contraintes, évaluation et recommandation

Optimal process design for the polygeneration of SNG, power and heat by hydrothermal gasification of waste biomass: Process optimisation for selected substrates

Based on a previously developed thermo-economic process model, this paper presents a detailed design study for the polygeneration of Synthetic Natural Gas (SNG), power and heat by catalytic hydrothermal gasification of biomass and biomass wastes in supercritical water. Using multi-objective optimisation techniques, the thermodynamic and thermo-economic performances of all candidate configurations from a general process superstructure are optimised with respect to SNG and electricity cogeneration and its associated investment cost, production cost and plant profitability. The paper demonstrates how both the optimal system configuration, its operating conditions and performances depend on the available technology, catalyst lifetime, process scale and the characteristics of the processed substrate

Application of Multi-Objective Optimisation to Process Measurement System

Multi-objective optimisation (MOO) has been used with an equation solver data reconciliation software to develop a tool for sensor system design based on modifying the sensitivity matrix of a simulated process. MOO enables searching for the best trade-off between two conflicting objectives: the cost of the system and the precision of key performance indicators (KPI) (variables that have to be measured or calculated). This methodology has been applied to design the sensor system of a two stage experimental air-water heat pump. Proper knowledge of modelling equations and constants helps to improve the estimation of the precision of variables, and lowers the cost of the system. Compared to single objective optimisation, the MOO strategy increases the number of solutions, yet the precision function still relates to different objectives for each KPI, and its formulation is shown to have an impact on the trade-off obtained

COVID-19 symptoms at hospital admission vary with age and sex: results from the ISARIC prospective multinational observational study

Background: The ISARIC prospective multinational observational study is the largest cohort of hospitalized patients with COVID-19. We present relationships of age, sex, and nationality to presenting symptoms. Methods: International, prospective observational study of 60 109 hospitalized symptomatic patients with laboratory-confirmed COVID-19 recruited from 43 countries between 30 January and 3 August 2020. Logistic regression was performed to evaluate relationships of age and sex to published COVID-19 case definitions and the most commonly reported symptoms. Results: ‘Typical’ symptoms of fever (69%), cough (68%) and shortness of breath (66%) were the most commonly reported. 92% of patients experienced at least one of these. Prevalence of typical symptoms was greatest in 30- to 60-year-olds (respectively 80, 79, 69%; at least one 95%). They were reported less frequently in children (≤ 18 years: 69, 48, 23; 85%), older adults (≥ 70 years: 61, 62, 65; 90%), and women (66, 66, 64; 90%; vs. men 71, 70, 67; 93%, each P < 0.001). The most common atypical presentations under 60 years of age were nausea and vomiting and abdominal pain, and over 60 years was confusion. Regression models showed significant differences in symptoms with sex, age and country. Interpretation: This international collaboration has allowed us to report reliable symptom data from the largest cohort of patients admitted to hospital with COVID-19. Adults over 60 and children admitted to hospital with COVID-19 are less likely to present with typical symptoms. Nausea and vomiting are common atypical presentations under 30 years. Confusion is a frequent atypical presentation of COVID-19 in adults over 60 years. Women are less likely to experience typical symptoms than men

Energy savings in methanol synthesis: Use of heat integration techniques and simulation tools.

Starting with a classical process for producing methanol using the reforming and synthesis steps, a combined approach applying simulation models and a new synthesis strategy, named Effect Modelling and Optimisation (EMO), has been used to optimise the energy efficiency of the process. The method allows to identify different ways of improving the energy efficiency of the process. The modifications concern the synthesis reactor and the reforming reactor designs, the exploitation of the purge stream as fuel gas to satisfy the process requirement and its integration to a gas turbine system. The EMO approach allows to target the impact of a process modification at the global level of the energy cost of the process, including the combined production of heat and mechanical power in a gas turbine and the steam network. Starting with a classical methane conversion of 60% for the classical system, we identify solutions with up to 93% of the overall methane conversion when we transform the net mechanical power produced into methane savings at the country level. The interest of the approach is the possibility of computing the impact of the process modifications suggested by the analysis of the shape of the heat cascade on the overall energy balance of the plant without having to simulate in many details the steam and the heat exchanger network