Biological nitrogen recirculation to food protein – A review

Nitrogen is a part of a complex cycle with transformative reactions being not only an essential element for living organisms, but also facilitating negative environmental impacts as eutrophication and climate change. To reduce the negative environmental impacts, closing the nitrogen loop, reducing inputs of fossil-based synthetic nitrogen fertilizers, and returning nitrogen-rich material and waste streams back into the food system are essential. This review investigates the potential of nitrogen transformation technologies to return nitrogen to food systems from existing material streams, levelling the imbalances of the nitrogen cycle. Review of both conventional and biotechnological pathways for nitrogen recovery, as well as of legal aspects and safety issues uncovers the knowledge gaps, potentials, and barriers for making nitrogen circular in a food system context. Further a few technologies aiming the recirculation of the nitrogen disclosed as a basis for potential industrial scale up and implementation.Peer reviewe

Protocol for a national audit on self-reported confidence levels, training requirements and current practice among trainee doctors in the UK: The Trainees Own Perception of Delivery of Care in Diabetes (TOPDOC) Study

Background: As the incidence and prevalence of diabetes increases across the world, resource pressures require doctors without specialist training to provide care for people with diabetes. In the UK, national standards have been set to ensure quality diabetes care from diagnosis to the management of complications. In a multi-centre pilot study, we have demonstrated a lack of confidence among UK trainee doctors in managing diabetes. Suboptimal confidence was identified in a number of areas, including the management of diabetes emergencies. A national survey would clarify whether the results of our pilot study are representative and reproducible. Methods/Design: Target cohort: All postgraduate trainee doctors in the UK. Domains Studied: The self reported online survey questionnaire has 5 domains: (1) confidence levels in the diagnosis and management of diabetes, (2) working with diabetes specialists, (3) perceived adequacy of training in diabetes (4) current practice in optimising glycaemic control and (5) perceived barriers to seeking euglycaemia. Assessment tools: Self-reported confidence is assessed using the 'Confidence Rating' (CR) scale for trainee doctors developed by the Royal College of Physicians. This scale has four points - ('not confident' (CR1), 'satisfactory but lacking confidence' (CR2), 'confident in some cases (CR3) and 'fully confident in most cases' (CR4). Frequency of aspects of day-to-day practice is assessed using a six-point scale. Respondents have a choice of 'always' (100%), 'almost always' (80-99%), 'often' (50-79%), 'not very often' (20-49%) and 'rarely' (5-19%) or never (less than 5%). Discussion: It is anticipated that the results of this national study will clarify confidence levels and current practice among trainee doctors in the provision of care for people with diabetes. The responses will inform efforts to enhance postgraduate training in diabetes, potentially improving the quality of care for people with diabetes.</p

Real-Time Monitoring of Microalgal Biomass in Pilot-Scale Photobioreactors Using Nephelometry

The increasing cultivation of microalgae in photobioreactors warrants efficient and non-invasive methods to quantify biomass density in real time. Nephelometric turbidity assessment, a method that measures light scatter by particles in suspension, was introduced already several decades ago but was only recently validated as a high-throughput tool to monitor microalgae biomass. The light scatter depends on the density of the suspended particles as well as on their physical properties, but so far there are hardly any accounts on how nephelometric assessment relates to classic methods such as dry weight and spectrophotometric measurement across a broad biomass density range for different microalgae species. Here, we monitored biomass density online and in real time during the semi-continuous cultivation of three commercial microalgae species Chloromonas typhlos, Microchloropsis gaditana and Porphyridium purpureum in pilot-scale photobioreactors, and relate nephelometric turbidity to dry weight and optical density. The results confirm a relatively strong (R2 = 0.87–0.93) and nonlinear relationship between turbidity and biomass density that differs among the three species. Overall, we demonstrate how nephelometry can be used to monitor microalgal biomass in photobioreactors, and provide the necessary means to estimate the biomass density of the studied species from turbidity data to facilitate automated biomass monitoring

Insects as diet and therapy : perspectives on their use for combating diabetes mellitus in Tanzania

More than 450 million people worldwide are suffering from diabetes and this number is expected to increase. In developing countries, such as Tanzania, the number of patients suffering from diabetes and associated diseases is increasing as well. Up to 80% of the Tanzanian people rely on traditional medicines for their health care services. The nature of Tanzanian is very rich in different plant and insect species, and this could be exploited through their implementation in preventive and/or curative approaches in the battle against diabetes. The implementation of healthy insects in the diets of people may help in the prevention of obesity, which is a risk factor in the etiology of diabetes, while the identification of small molecules in insects may help in the discovery of potential new drugs that can be used in the treatment of diabetes. In this paper, an overview on the potential implementation of insects against diabetes is presented

Risks related to the presence of Salmonella sp. during rearing of mealworms (Tenebrio molitor) for food or feed: Survival in the substrate and transmission to the larvae

© 2019 Elsevier Ltd During rearing of insects for food and feed, their microbial safety is of utmost importance, but little is known on the transmission of food pathogens from the substrate to the insects. The aim of this study was to investigate whether transmission of Salmonella sp. to mealworms (Tenebrio molitor) can occur, in case mealworms are fed with contaminated wheat bran as substrate. Three consecutive contamination levels of a mixed culture of three Salmonella enterica strains in wheat bran were studied, being 7, 4, and 2 log cfu/g. At each of these contamination levels, Salmonella sp. remained present in the bran during the experimental period of seven days when larvae were absent. This indicates that Salmonella sp. can survive for at least seven days when wheat bran is stored, as is done in industrial rearing facilities. When larvae were present, however, the survival of Salmonella sp. in larvae and bran depended on the contamination level. When bran was contaminated with 7 log cfu/g Salmonella sp., the bacterium was still present after seven days in both larvae and bran, with average numbers of 3.7–4.1 log cfu/g, respectively. At a contamination level of the bran of 4 log cfu/g, Salmonella sp. counts decreased until <1.5 log cfu/g and <1.0 log cfu/g on average in bran and larvae, respectively. However, the pathogen was still detected in most larvae and bran samples after seven days, as was shown using presence/absence testing. At a contamination level of 2 log cfu/g, presence/absence testing revealed Salmonella sp. to remain present in some bran samples after seven days, but surprisingly was not detected in the larval samples. Apparently, when present at a low level in the substrate, Salmonella sp. is not retained by the larvae during the seven day period, likely either because of competitive exclusion by the endogenous larval microbiota and/or because of antibacterial activity of the larvae.status: publishe