Background: Street foods vary with respect to their nutritional value and safety characteristics and contribute to a sizable proportion of food intake in many populations worldwide. Therefore, the present study aimed to describe the coverage in the scientific literature of different health-related and socio-economic aspects of street food consumption and trading. Methods: Three electronic databases (searched from inception to 16 October 2017), a hand-search of relevant journals and backward citation tracking were used to identify eligible scientific articles with a main objective of investigating or reporting specific results on health-related or socio-economic aspects of street food. Papers published in English, Portuguese, French, Spanish or Italian, as well as English abstracts of papers published in other languages, were assessed. The selected articles were evaluated by two independent researchers and described according to year of publication, geographical distribution, definition of street food, main topics addressed and target population. Results: In total, 441 papers were selected. The number of publications has increased in recent years, almost half of them being published after 2012. Almost three-quarter of the articles were from Africa or Asia. Most studies addressed food safety (85.5%), whereas street food availability and consumption were much less frequently investigated (30.3%). The focus of the studies was usually the food (mostly its microbiological contamination) and the vendors (mostly their food handling), whereas consumers and vending sites were seldom evaluated. More than half of the studies did not specify a definition for street food. Conclusions: Efforts are needed for a more widespread and comprehensive assessment of different issues related to street food availability and consumption in different settings, especially regarding street food offer, nutritional composition, and patterns of purchase and consumption by the population. 152

Background Although an increasing body of data reports the detection of SARS-CoV-2 RNA in air, this does not correlate to the presence of infectious viruses, thus not evaluating the risk for airborne COVID-19. Hence there is a marked knowledge gap that requires urgent attention. Therefore, in this systematic review, viability/stability of airborne SARS-CoV-2, SARS-CoV and MERS-CoV viruses is discussed. Methods A systematic literature review was performed on PubMed/MEDLINE, Web of Science and Scopus to assess the stability and viability of SARS-CoV, MERS-CoV and SARS-CoV-2 on air samples. Results and discussion The initial search identified 27 articles. Following screening of titles and abstracts and removing duplicates, 11 articles were considered relevant. Temperatures ranging from 20 °C to 25 °C and relative humidity ranging from 40% to 50% were reported to have a protective effect on viral viability for airborne SARS-CoV and MERS-CoV. As no data is yet available on the conditions influencing viability for airborne SARS-CoV-2, and given the genetic similarity to SARS-CoV and MERS-CoV, one could extrapolate that the same conditions would apply. Nonetheless, the effect of these conditions seems to be residual considering the increasing number of cases in the south of USA, Brazil and India, where high temperatures and humidities have been observed. Conclusion Higher temperatures and high relative humidity can have a modest effect on SARS-CoV-2 viability in the environment, as reported in previous studies to this date. However, these studies are experimental, and do not support the fact that the virus has efficiently spread in the tropical regions of the globe, with other transmission routes such as the contact and droplet ones probably being responsible for the majority of cases reported in these regions, along with other factors such as human mobility patterns and contact rates. Further studies are needed to investigate the extent of aerosol transmission of SARS-CoV-2 as this would have important implications for public health and infection-control policies.

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h i g h l i g h t sMedium pH for the lipid and carotenoid production by R. toruloides is different. A dual step pH control fed-batch strategy improved the yeast products production. The oxygen played a crucial rule in the yeast carotenoid synthesis. t r a c tThe optimal medium pH to produce biomass and fatty acids by the red yeast Rhodosporidium toruloides NCYC 921 is 4.0, and to produce carotenoids is 5.0. Based on this difference, a dual-stage pH control fed-batch cultivation strategy for the enhancement of lipids and carotenoids production by this yeast was studied. The results showed that when the yeast growth phase was conducted at pH 4.0, and the products accumulation phase was conducted at pH 5.0, biomass, total fatty acid and total carotenoid productivities were significantly improved comparing with the yeast fed batch cultivations carried out at fixed medium pH (4 or 5). Under dual-stage pH control conditions, the biomass, carotenoids and lipids productivities attained 2.35 g/L h, 0.29 g/L h and 0.40 g/L h, respectively. It was also observed that the oxygen played a major role in the yeast carotenoid production.

Background: A nutrition transition is occurring in the urban areas of developing countries, where street food makes an important contribution to daily food intake. Aim: We aimed to characterise street food offer in Maputo, Mozambique, and to evaluate the nutritional composition of the most common homemade foods. Methods: A cross-sectional study was conducted in 2014. Streets in the surroundings (500 m buffer) of randomly selected public transport stops in KaMpfumu district, Maputo, were canvassed to identify all street food vending sites (n ¼ 968). Information regarding vending site characteristics and the food offered was gathered through interview and observation. Samples (n ¼ 80) of the most common homemade foods were collected for laboratorial analysis. Results: Most street food vending sites identified were stationary (77.4%) and sold exclusively industrial food (51.9%). Frequency of fruit, beverages and food other than fruit was 24.5%, 32.5% and 73.9%, respectively. Fried cakes were the most energy-dense (430 kcal/100 g), and richest in fats (21.0g/100 g) and carbohydrates (53.4 g/100 g). The richest sources of protein were the stewed meat/fish/ liver dishes (10.7-11.6 g/100 g). Fried cakes showed the lowest sodium and potassium content (90 mg/100 g and 81 mg/ 100 g, respectively) whereas hamburgers exhibited the highest content of those micronutrients (455 mg/100 g and 183 mg/100 g, respectively). Stewed liver dishes presented the highest sodium/potassium ratio (11.95). Fried snacks presented the highest trans-fatty acid content (0.20 g/100 g). Conclusions: Street food in Maputo is abundant and scattered throughout the urban district, exhibiting high variability in the nutritional composition of homemade foods. Public health policies should be targeted to improve the street food offer, promoting nutrient-dense foods and the reduction of added salt.