Quality Characteristics and Consumer Exposure to Sulphur Dioxide From Fruit-based Nonalcoholic Beverages Commercially Traded in Nairobi

Abstract

A diversity of fruit based non- alcoholic beverages, locally produced, and imported are sold and consumed in Kenya. The choice preservative for these beverages is Sulphur dioxide, making it one of the potential causes of exposure to Sulphur dioxide (SO2). Therefore, the aim of this study was to establish the presence of Sulphur dioxide residues in the fruit-based non-alcoholic beverages that are widely consumed in Nairobi, Kenya with a view to determining the level of exposure of the chemical to the Kenyan consumer. A Total of 384 fruit based beverage samples were sampled and collected from the major supermarket chains in Nairobi, Kenya using a self-structured guide, followed by analysis for Sulphur dioxide residues, pH and total soluble solids (°Brix) content using Tanner titration, potentiometric and refractrometric method, respectively. The dietary exposure of Sulphur dioxide to the Kenyan consumer was determined using a deterministic method. Sulphur dioxide exposure was then compared to the respective acceptable daily intake (ADI). Results showed that most of the beverages had SO2 residual levels, pH and total soluble solids content that were within the specifications set in the Kenya Standards. The SO2 residue levels in ready- to- drink fruit drinks, fruit juices, fruit nectars; and the dilutable fruit drinks were 1.25±2.58, 0.56±1.71, 0.49±1.47 and 21.52±13.85 mg/kg respectively, compared to the tolerated level of 10 mg/kg maximum. Only 13.1% fruit juices, 12% of fruit nectars and 22.5% of fruit drinks contained Sulphur dioxide residues, which were all within the acceptable level. However, of the 86.3% of dilutable fruit drinks contained Sulphur dioxide residues, of which 71.3% had Sulphur dioxide residues above the acceptable limit. Therefore, the main source of SO2 exposure comes from the dilutable fruit drinks. Daily intakes of SO2 from consumption of fruit-based beverages were 0.032, 0.21, and 0.20 mg/kg body bw/day in preschool children aged 3-6, 7-18 years group and adults respectively, which were all below the 0.7 mg/kg b/t/day ADI set by JECFA; while risk of Sulphite exposure was 5 %, 3 % and 3 % of the ADI for preschool children, children aged 7 to 18 and adults aged 19 years and above, respectively. In conclusion, exposures from consumption of fruit- based beverages were within the relevant Acceptable Daily Intake (ADI) for all population groups including the high-end consumers. However, frequent overindulgence on dilutable drinks, even in low at low levels can pose a health risk to SO2-sensitive individuals, hence should be aware of the risks associated with high levels of residual SO2.