Overview
The authors digested khoa, paneer and curd from local dairy shops with nitric and hydrochloric acid and measured lead, cadmium, copper, iron and zinc by flame atomic absorption. Lead, cadmium and copper were printed as 0 ppm in all three products; only iron and zinc were reported as present. Milk is named in the collection step but no milk result is given.
Key numbers
- Khoa, paneer and curd: lead “0 ppm” and cadmium “0 ppm” (Table 1), recorded as non-detects because no detection limit is given.
- Zinc: khoa 0.699 ppm, paneer 1.874 ppm, curd 0.972 ppm (Table 1).
- Iron: khoa 0.681 ppm, curd 0.156 ppm (Table 1).
Methods (brief)
Wet acid digestion (about 3 hours for khoa and paneer, 2 hours for curd), filtration, dilution to 25 mL and flame atomic absorption. A reagent blank was used as the zero standard. No detection limits, reference materials, recoveries or replicate counts are reported.
Evidence Fitness
Very weak: one value per product with no sample count, no detection limit and no quality control, from an undergraduate project report. The non-detects carry no usable limit. These are concentrated or fermented milk products, so the paper is a proxy for reduced-fat milk and does not measure it.