Release of lead from glaze-ceramicware into foods cooked by open flame and microwave

Samples of ceramicware (24 bowls), purchased from a single manufacturer lot and 36 bowls were collected randomly from a local market in Great Cairo Governorates, Egypt (six locations and six samples from each) and were subjected to different concentrations of acetic acid (2, 4, 6 and 8%) to investigate the release of lead. Results showed that the 4% acetic acid solution was the best concentration for lead extraction from ceramicware followed by 6, 8 and 2%. Release of lead from ceramicware by acetic acid caused a visible erosion of the surface glaze on each bowl. On the other hand, a great variability between the levels of leachable lead and their locations during the extraction time (20 extractions) was also observed. Transfer of leachable lead from ceramicware into foods (salsa and beans) cooked by traditional and microwave methods was also studied. Results revealed that the correlation between the cooking time of salsa by the traditional method and leachable lead was approximately linear. Moreover, the concentration of lead in the final product (salsa) cooked by the traditional method was higher (15.0 ppm) than in that cooked by a microwave method. However, there were no significant differences between the leachable lead levels into beans cooked either by traditional or microwave methods. Slightly visible erosion in the surface glaze of bowls after cooking was also observed.