Overview
Beyhan and colleagues measured 11 elements by flame atomic absorption in bitter, milk and white chocolates from eight manufacturers bought in Burdur, Turkey. Cadmium, chromium, lead and nickel were not detected in any sample. Copper, iron and zinc are reported per brand and chocolate type.
Key numbers
- Cadmium, chromium, lead and nickel: “not detected” in all 24 chocolates, “lower than the value of LOD for FAAS detection” (Section 3.6, pp. 461-462); no LOD value is given.
- Iron in bitter chocolate: 8.9 to 363 mg/kg across brands (Table 8).
- Zinc in bitter chocolate: 29.7 to 65 mg/kg (Table 9).
Methods (brief)
About 1 g of chocolate was microwave-digested in nitric acid and hydrogen peroxide and read by flame atomic absorption in triplicate. Results are given as mean ± a 95 percent confidence half-width. Accuracy was checked only for manganese in a spinach reference material (91 percent recovery).
Evidence Fitness
Small sample (one product per brand and type) and a method with unstated and probably high detection limits for the toxic metals, so the non-detects say little about lead or cadmium at regulatory levels. No QA for lead or cadmium. Chocolate is a proxy for chocolate pudding and chocolate nut candy, which are not linked.