Mineral content in commercially branded and local salt in selected villages from Bahi, Iramba, Manyoni, and Singida urban districts, Tanzania

Abstract

The study examines the mineral content of table salts used by households in villages adjacent to the production areas. A total of 210 samples from commercial and local salts were collected, and analyzed using iodometry titration, spectrophotometry, colorimetry, and atomic absorption spectroscopy (AAS) techniques, followed by a household interview for salt type preference. The lowest detectable concentration LOD, lowest quantifiable concentration LOQ and, recovery of methods ranged (0.32–2.155 μg/kg), (0.117–6.387 μg/kg) and, (94.2–103.6 %), respectively. Significant differences in mineral contents were observed within and between local and commercially branded salts (p < 0.001). The mean iodine in the local salt samples from Kitangiri (SA), Singidani (SB), Kindai (SC), Chibumagwa (SD), and Sulunga (SE) ranged from 10.5 ± 0,02 to 16.9 ± 0.01 mg/Kg, with only SA and SC in the World Health Organization (WHO) limits, while commercially branded salt samples SF (Malindi), and SG (Dar es salaam) ranged from 23.4 ± 0.01 to 35.9 ± 0,02 mg/kg that were in the Tanzania Bureau of Standards (TBS) and WHO agreed range. Other ions recorded were nitrate (3.3–4.4 mg/kg, 5.45–7.40 mg/kg), phosphate (0.02–0.48 mg/kg, 0.03 mg/kg), sulphate (0.31–0.42 mg/kg, 0.03–0.07 mg/kg), ammonia (0.5 mg/kg, 0.5 mg/kg to 0.6 mg/kg), copper (1.0–2.0 mg/kg, 0.9–2.0 mg/kg), iron (0.5–1.8 mg/kg, 0.9 mg/kg), and manganese (0.5–1.8 mg/kg, 0.9 mg/kg) for local and commercially branded salt, respectively. Households preferred local to commercial-branded salts: Nkonkilangi 163 (69.9, 32.1 %), Mangwanjuki 96 (17.2, 82.8 %), Unyanga 54 (26.7, 73.3 %), Chibumagwa 106 (63.0, 37.0 %), and Chali Igongo 51 (74.6, 25.4 %), respectively. Public health interventions are recommended to promote the consumption of adequately iodized salt for informed dietary choices.