Overview
Shaikh and Samant screened nine ready-to-eat products for zinc, cadmium, lead and copper by sample DC voltammetry, preparing each product two ways: a warm dilute hydrochloric acid “digestive” extraction and dry ashing. Each product is a single sample, and many results are below an unstated detection limit. The authors conclude the products are safe, although several printed values are high.
Key numbers
- Ashing (total): Soup B lead 6.6 mg/kg; Noodles C cadmium 1.3 and lead 2.8 mg/kg; Soup A all four metals “BDL” (Table 4).
- Digestive extraction: Noodles B lead 7.2 mg/kg; Noodles C cadmium 4.0 mg/kg; Soup A cadmium 0.4 and lead 1.2 mg/kg (Table 3).
Methods (brief)
Five grams were soaked in 0.1 N hydrochloric acid and boiled, or ten grams were ashed at 800 to 900 °C and dissolved in hydrochloric acid; metals were measured on a static mercury drop electrode by standard addition. No detection limits, reference materials or recoveries are reported.
Evidence Fitness
Very small (one sample per brand), no quality control, and the two preparations disagree in both directions, so values are low-confidence screening data. The soups are of unstated type, so they are a proxy for broccoli-cheese-soup, chicken-noodle-soup, cream-of-potato-soup and vegetable-beef-soup; instant noodles are a proxy for ramen-soup, oats for cereal and pasta (whole-grain status not stated) for whole-wheat-pasta. None of those thin pages is linked.