An investigation to assess the spatial structure and severity of Pseudocercospora leaf and fruit spot disease (PLFSD) on citrus trees in cocoa-based agroforests was carried out in three contrasting ecological zones in...An investigation to assess the spatial structure and severity of Pseudocercospora leaf and fruit spot disease (PLFSD) on citrus trees in cocoa-based agroforests was carried out in three contrasting ecological zones in southern Cameroon, viz: 1) the humid forest zone, 2) the degraded forest zone, and 3) the forest-savannah transition zone. Two main parameters were investigated viz: 1) the spatial structure of cocoa based agroforests, and 2) the disease severity. In total, the spatial structure of 19 cocoa-based agroforests was analysed using the Ripley K(r) function, meanwhile the collection of epidemiological data that consisted of noting the presence of PLFSD spots on leaves and fruits on 438 citrus trees was used to characterise the severity of the disease. Results showed that, the spatial structure of citrus trees in these agroforests investigated were regular in seven plots, random in nine, and aggregated in three. Aggregated plots presented a significantly higher mean of disease severity on leaves and fruits (28.55 and 30.37 respectively), as compared to randomised (20.91 and 16.32 respectively) and regular plots (16.28 and 14.97 respectively), at P-value < 0.05. These results suggest that the spatial structure of citrus trees in the cocoa-based agroforests studied influences the severity of PFLSD. Proper integrated control measures can therefore be initiated, leading to a considerable reduction of the use of manufactured inputs, and thereby, the cost of production of citrus fruits.展开更多
Background:The World Health Organization has expressed concern about arsenic,cadmium,lead,and mercury as potentially harmful to human health.As such,the world body has called for appropriate preventive and interventio...Background:The World Health Organization has expressed concern about arsenic,cadmium,lead,and mercury as potentially harmful to human health.As such,the world body has called for appropriate preventive and interventionary measures.In response,food regulatory bodies including European Food Safety Authority are monitoring the levels of these heavy metals in cocoa and cocoa products.Objective:Therefore,the objective of this paper is to synthesize the latest relevant available peer-reviewed publications on arsenic,cadmium,lead,and mercury with a view to highlighting the gaps to encourage further research and informing industry.Materials and Methods:A systematic review was conducted using the European Food Safety Authority guide in PubMed database and the result was reported according to the PRISMA checklist.Results:The results show that processing may dilute or concentrate the levels of arsenic,cadmium,lead,and mercury,depending on processing factors including the product type,processing method,and raw materials.In addition,some products exceed the European Union and Chinese Maximum Contaminant Level and may pose risk.Furthermore,the findings show that the risk of heavy metal toxicities was higher among children relative to adults at the same exposure in cocoa-based products and that correcting risk estimates for bioavailability reduces the level of estimated risk.Conclusion:Therefore,the review concludes that further research is required to clarify the effect of processing on the level of these contaminants in specific cocoa-based foods.Moreover,conducting risk studies based on age groups and correcting for bioavailability of arsenic,cadmium,lead,and mercury enhance accuracy of risk estimates.Recommendations:The review,therefore,recommends that a value chain approach be adopted to assessing the levels,exposures,and risks of arsenic,cadmium,lead,and mercury in cocoa-based foods and the effect of processing on these levels.展开更多
文摘An investigation to assess the spatial structure and severity of Pseudocercospora leaf and fruit spot disease (PLFSD) on citrus trees in cocoa-based agroforests was carried out in three contrasting ecological zones in southern Cameroon, viz: 1) the humid forest zone, 2) the degraded forest zone, and 3) the forest-savannah transition zone. Two main parameters were investigated viz: 1) the spatial structure of cocoa based agroforests, and 2) the disease severity. In total, the spatial structure of 19 cocoa-based agroforests was analysed using the Ripley K(r) function, meanwhile the collection of epidemiological data that consisted of noting the presence of PLFSD spots on leaves and fruits on 438 citrus trees was used to characterise the severity of the disease. Results showed that, the spatial structure of citrus trees in these agroforests investigated were regular in seven plots, random in nine, and aggregated in three. Aggregated plots presented a significantly higher mean of disease severity on leaves and fruits (28.55 and 30.37 respectively), as compared to randomised (20.91 and 16.32 respectively) and regular plots (16.28 and 14.97 respectively), at P-value < 0.05. These results suggest that the spatial structure of citrus trees in the cocoa-based agroforests studied influences the severity of PFLSD. Proper integrated control measures can therefore be initiated, leading to a considerable reduction of the use of manufactured inputs, and thereby, the cost of production of citrus fruits.
文摘Background:The World Health Organization has expressed concern about arsenic,cadmium,lead,and mercury as potentially harmful to human health.As such,the world body has called for appropriate preventive and interventionary measures.In response,food regulatory bodies including European Food Safety Authority are monitoring the levels of these heavy metals in cocoa and cocoa products.Objective:Therefore,the objective of this paper is to synthesize the latest relevant available peer-reviewed publications on arsenic,cadmium,lead,and mercury with a view to highlighting the gaps to encourage further research and informing industry.Materials and Methods:A systematic review was conducted using the European Food Safety Authority guide in PubMed database and the result was reported according to the PRISMA checklist.Results:The results show that processing may dilute or concentrate the levels of arsenic,cadmium,lead,and mercury,depending on processing factors including the product type,processing method,and raw materials.In addition,some products exceed the European Union and Chinese Maximum Contaminant Level and may pose risk.Furthermore,the findings show that the risk of heavy metal toxicities was higher among children relative to adults at the same exposure in cocoa-based products and that correcting risk estimates for bioavailability reduces the level of estimated risk.Conclusion:Therefore,the review concludes that further research is required to clarify the effect of processing on the level of these contaminants in specific cocoa-based foods.Moreover,conducting risk studies based on age groups and correcting for bioavailability of arsenic,cadmium,lead,and mercury enhance accuracy of risk estimates.Recommendations:The review,therefore,recommends that a value chain approach be adopted to assessing the levels,exposures,and risks of arsenic,cadmium,lead,and mercury in cocoa-based foods and the effect of processing on these levels.
