Levels of Benzoic Acid, Sulphur (IV) Oxide and Sorbic Acid in Carbonated Drinks Sold in Lagos, Nigeria

Abstract

Residual sulphite as sulphur dioxide causes severe systemic reaction characterised by difficulty in breathing and cardiovascular collapse. Few studies have described exposure of humans to excessive preservatives from food and beverage products in Nigeria. Little is also known about the levels of preservatives such as benzoate, sorbates, sulphur (IV) oxide, sorbic acid and ascorbic acid in carbonated drink (CD) ,fruit juices (FJ), sport drinks(SD) and dairy drinks. Commonly consumed carbonated drinks (14), fruit juices (14), sport drinks (2) and dairy drinks (3) purchased in various markets in Lagos metropolis were analysed for the preservative contents using standard methods. Residual sulphite levels expressed as sulphur (IV) oxide in CD ranged from 4.0 – 15.2 mg/L, FD ranged from ND-13.6 mg/L. SD ranged from 3.6-13.6 mg/L while in DD it ranged from ND – 4.7 mg/L. Benzoic and citric acid contents for CD, FJ, SD and DD ranged from 222-702 mg/L & 0.38-0.89% m/v ; 168-799 mg/L & 0.26-0.89% m/v; 451-494 mg/L & 0.24-0.32% m/v; 132-318 mg/L & 0.36-0.7% m/v, respectively. The pH of the drinks ranged from 2.46-5.58. 55% of the samples analysed have benzoic acid content below the regulatory limit. Values of pH, ascorbic acid and sulphur (IV) oxide for all samples were in conformity with standards. Benzoic acid and ascorbic acid concentration was higher in Sport drinks than other samples while levels of sulphur (IV) oxide and citric acid were more in carbonated drinks. The citric acid values of about 21% of the samples analysed had value above required limit of 0.5%m/v. The sum total of the preservatives levels are within the regulatory limit, however, 71.4% of the carbonated and 100% of the fruit drinks have benzoic acid level above the national permitted level of 250 and 150 mg/L respectively.