MICROBIOLOGICAL QUALITY AND LEVEL OF HEAVY METALS IN EDIBLE VEGETABLE OILS PRODUCED AND MARKETED IN GONDAR CITY

Abstract

ABSTRACT Introduction: Edible oils are imported and produced in Ethiopia, notably in Gondar, its production has expanded considerably in recent years. The expansion of locally produced edible vegetable oils, along with a lack of severe quality control, has resulted in a high level of susceptibility to their health-related quality. Substandard edible oil production and quality deterioration may contribute to the formation of reactive and hazardous oxidation products which may cause public health problems. Objective: To determine microbiological quality and levels of certain heavy metals of edible vegetable oils being produced and marketed in Gondar city, northwest Ethiopia. Methods: A laboratory-based cross-sectional study design was conducted from May to July 2021 in Gondar City. Simple random sampling techniques was used to collect 51 edible oil samples. Aseptically collected samples were analyzed in biology/chemistry lab room using selected oil quality parameters. Digestion of the samples was carried out using microwave. Analysis of heavy metals was carried out using atomic absorption spectrophotometer. Microbiological quality of vegetable oil was assessed by using standard microbiological procedures and techniques to enumerate, isolate, identify and characterize the different microorganisms associated with the oils assessed. To make the frequency distribution more symmetrical, microbial data was first converted to Log 10 values to determine fungal and bacterial load of oil samples. The collected data were entered to Microsoft Excel and Stata Version 17 and Non- parametric Kruskal Wallis test was used to assess significant variations. Result; Fifty-one vegetable edible oil samples were examined which contain varying number of bacteria, yeast and Molds. Staphylococcus. aureus, Klebsiella Pneumonie, Pseudomonas. Aeruginosa were the identified bacteria whereas Saccharomyces cerevisiae, Aspergillus Niger, Aspergillus flavus, Aspergillus fumigatus were the identified fungi. Total coliform and fecal coliform isolates were identified. The total aerobic bacterial plate count ranged from 7.5×104 to 2.01× 105 cfu/mL with locally produced mixed oil having the highest bacterial load and sample of Niger seed oil from market site had less count. The yeast and mold count of oil samples ranged from 0 to 9×104 cfu/mL. The concentration of heavy metals were observed in the range of 0.01-