Aluminum levels in convenience and fast foods: in vitro study of the absorbable fraction

We evaluated the levels of aluminum in a total of 120 samples of 35 different convenience and fast foods that are widely consumed in Spain. Aluminum was determined in the samples mineralized with HNO3, HClO4 and V2O5, using electrothermal atomic absorption spectrometry as the analytical technique. Reliability of the procedure was checked by statistically comparing the results with those obtained with a previous microwave oven mineralization stage and by analysis of several certified reference materials. No matrix effect was observed and aqueous standard solutions were used for calibration. The detection limit was 4.0 pg and the characteristic mass of 10.0 pg. Aluminum concentrations ranged from 0.85 to 38.10 μg/g, refereed to fresh weight of the edible portion. The presence of this metal was detected in all the samples we analyzed, but the most elevated levels were encountered in pork- and chicken- based foods (mean 8.45 and 13.94 μg/g, respectively). The more elevated Al concentrations were detected in foods with a greater content of spices and aromatic herbs, pasta, certain vegetables and additives, and foods packaged in Al vessels. The absorbable fraction of Al estimated with in vitro assays was between 0.85 and 2.15%. The growing popularity of these products in recent years requires additional data and a periodical control. In addition, the present findings are of potential use to efforts aimed at determining tolerable levels of Al intake from the diet.