Analysis of heavy metals and minerals in edible vegetable oils produced and marketed in Gondar City, Northwest Ethiopia

Abstract

Abstract Introduction Nowadays, food safety is regarded as one of the most critical global public health issues. Edible oil, a key ingredient in food processing, is widely used and consumed in every Ethiopian household. However, its safety is often overlooked. Currently, edible oil is produced in Ethiopia from small-scale operations to large industrial levels, as well as imported from other countries. Objective This study aimed to determine the levels of heavy metals and essential minerals in edible vegetable oils produced and marketed in Gondar City, Northwest Ethiopia. Methods A laboratory-based cross-sectional study was conducted from May to July 2021 in Gondar City. Seventeen edible oil samples were collected using simple random sampling techniques. Heavy metal content was determined using an atomic absorption spectrophotometer with the standard procedures and techniques after microwave digestion. The efficiency and validity of the method used were evaluated by determining the limit of detection (LOD), the limit of quantification (LOQ), accuracy, and precision. The collected data were entered into Microsoft Excel and transported to Stata for analysis. Result A total of seventeen vegetable oil samples were analyzed. The accuracy of the method was evaluated by recovery studies, which ranged from 81 to 115%, and the relative standard deviations were found to be below 15%. The concentrations of Zn, Cu, Fe, Cd, and Pb were in the range of 0.07 to 0.8 mg/l, 0.002 to 0.06 mg/l, 0.01 to 0.8 mg/l, 0.08 to 0.18 mg/l, and 0.003 to 0.27 mg/l, respectively. In general, the lead and cadmium content was higher than other metals in some of the investigated edible vegetable oils. Most values fell within the permissible quality limits for edibility as prescribed by the World Health Organization (WHO) and the National Agency for Food and Drug Administration and Control (NAFDAC). However, the levels of Pb and Cd exceeded the reference levels in some locally produced vegetable oils. Conclusion To address the exceeded levels of heavy metals, it is imperative to implement more careful handling, processing of raw materials, and filtering practices. Producers and marketers should take the necessary precautions to prevent contamination. Strict regulatory control from responsible bodies and stakeholders is recommended to ensure the safety and metal contents of vegetable oils originating from the study area.

Keywords

• Edible vegetable oil
• Essential nutrient
• Locally made
• Heavy metal
• Gondar