Cooking Pots: A Source of Heavy Metal Contamination of Food and Water

Introduction: Certain kitchen utensils used for food preparation can present significant risk because they are manufactured with materials such as aluminum, stainless steel and enamel that can be hazardous or contaminate food when heated.

Aim: The aim of this study was to determine the microbial and heavy metals found in leachates from some cooking utensils subjected to heating.

Methodology: A total of four aluminum and stainless steel cooking pots were used and seven hundred and fifty (750) millilitres of tap water was boiled for 15 minutes to 30 minutes in each of the pots at boiling point of 100°C. The analyses of the water samples for bacteria were carried out using the conventional standard procedures of isolating and identifying bacteria. The physicochemical parameters were quantified with the APHA method whereas the Atomic Absorption Spectrophotometer (AAS) was used for the determination of heavy metals.

Results: The results showed that Pseudomonas spp and Staphylococcus spp were isolated from some of the water samples that were not boiled while the boiled water showed no bacteria growth. The physicochemical parameters of the water samples before boiling were pH 5.36 to 7.41, temperature 30.7°C to 31.0°C, turbidity 0.04 to 1.41NTU, total dissolve solids 50.0 to 114.9 mg/l and others, while the presence of heavy metals such as Lead (Pb), Zinc (Zn), Iron (Fe), Cadmium (Cd) and Chromium (Cr) were detected in leachates from the pots subjected to heating. The values obtained were higher in leachates from pots that were heated for longer period. The oldest pot of thirty (30) years had a value of 0.0175±0.0007 mg/l to 0.0275±0.0021 mg/l for Zn while the value for Cd was 0.1110±0.0014 to 0.1245±0.0007 mg/l and the values for the newest pot was 0.0505±0.0021 to 0.0775±0.0035 mg/l for Pb and 0.0455±0.0248 mg/l to 0.0515±0.0191 mg/l for Cr.

Conclusion: Cadmium values in all the pots exceeded the control and World Health Organization (WHO) recommended values. It may be concluded that heavy metals leached out into water and food from some pots when heated for longer periods and this may become one source of exposure of heavy metals into the human body that may bioaccumulate to create health problems.