Safety of out-of-season longan consumption

Abstract

 Introduction: Nowadays, out-of-season longan production in Thailand was generally stimulated by potassium chlorate. As the chemical is prohibited in food, this study was aimed to assess the health risk from consumption of these longan fruits. Materials and Methodology: Three different doses of potassium chlorate were applied on longan trees via root (each dose, n=5), and a control group (n=2). After 210 days of application, the longan fruits samples (ready-to-eat fruits) were collected. After extraction with water, the extracts reacted with indigo carmine and 6M HCl were analyzed for chlorate residues using UV-Spectrophotometer at 610 nm. Then, assessment of the health risk by Margin of Safety (MOS) was performed. Results: The highest concentration of chlorate residues in longan fruits was found in group 3 (960 g potassium chlorate/tree) at 0.2254±0.0004 µg/g and the lowest concentration was in control group at 0.0326±0.0001 µg/g. The risk assessment found that consumption of 10 fruits/day, 500 and 1,000 g/day of all treated fruits were safe as Margins of Safety were all higher than 1. Therefore, no adverse effects on health should be worried from consumption of out-of-season longan fruits in general population.