Metal Leaching from Traditional Cookware: Could it be a Public Health Concern
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Date
2015-03
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Addis Ababa University
Abstract
Geogenic and anthropogenic activities are the bases for the contamination and entrance of
metals into the food chain and poses health risk. Therefore, in the present work, leaching of
some selected metals (Aluminium, Iron, Lead and Nickel) in traditional cooking pot
manufactured in unstandardized condition was investigated. Factors that can influence metal
leaching from cooking wares such as pH of food, cooking duration and cooking frequency
were studied. Sauce was made simulating the usual preparation. Levels of metals were
determined by Flame Atomic Absorption Spectrophotometer following high temperature
assisted wet acid digestion in a closed model. In addition, same metals were determined in
sauce prepared in a beaker as a control to rule out the effect of metal concentration in a sauce.
To study the effect of pH and boiling duration on the level of metal leaching, buffers of
Sodium citrate (pH 4.0) and Tris (pH 7.0 and 9.0) was boiled for 2 hrs. and samples were
regularly drawn every 12 min. for the first one hour and every 30 min. for the next one hour
of boiling. The mean (±SD) Al content of the foodstuffs was; onion (9.82±0.17 mg/kg);
berbere, (18.8±0.35 mg/kg); shiro powder, (39.15±0.27 mg/kg); and tomato, (1.6±0.04
mg/kg). The Fe content of the foodstuffs was ranged from 15.2±0.2 to 30.51±0.4 mg/kg.
Nickel content was found to be highest in shiro powder (3.42 ±0.66 mg/kg), followed by
Berbere (2.80±0.66 mg/kg), tomato (0.92±0.08 mg/kg), and onion (0.64±0.23 mg/kg). The
level of Al (38.38±0.3 mg/kg) and Fe (55.07 ± 2.11) in tomato sauce prepared in a beaker was
found to be significantly different (p<0.001) as compared with first time (Al, 203.68±2.03
mg/kg; Fe, 112.62±1.1 mg/kg), second time (Al, 176.82±2.8 mg/kg; Fe, 109.79±3.4 mg/kg),
third time (Al, 152.69±3.2 mg/kg ;Fe, 84.76 ± 1.23 mg/kg), and fourth time (Al, 142.94±2.7
mg/kg; Fe, 67.20±0.6 mg/kg) usage of the cooking pot. However, lead was not detected in
any of the food. Acidic pH had higher (p<0.001) leaching effect on Al (17.4±1.9 mg/kg) and
Fe (2.80±1.6) compared to leaching at alkaline (Al, 12.64±4.1 mg/kg Fe, 0.99±0.3 mg/kg) and
neutral pH (Al, 1.5±0.5 mg/kg Fe, 0.5±0.3 mg/kg).
In addition, cooking duration had a significant increasing effect (p<0.001) on leaching of Al
and Fe at all pH values. Similarly, the interaction of pH and boiling duration had significant
(p<0.001) on leaching of Al and Fe. Results of the present investigation indicate that leaching
of metals from unstandardized traditional cooking wares is significant and could be public
health concern. In addition, acidic pH and cooking duration increases metal leaching.
Keywords: cooking pot; leaching; Metals; cooking frequency; pH; boiling duration
Description
Keywords
cooking pot; leaching; Metals; cooking frequency; pH; boiling duration