Overview
Okoye and colleagues bought 14 batches of three sachet tomato paste brands in Awka, Nigeria, and measured lead, cadmium, chromium, zinc, copper and manganese by flame AAS, with triplicates per batch. Table 1.0 gives a mean and SD per batch on a wet-weight basis and compares batches by ANOVA and Tukey tests. The authors conclude that lead and cadmium stayed below the Codex levels they cite.
Key numbers
- Lead: batch means from “0.017 ± 0.002” (A4) to “0.089 ± 0.004” mg/kg wet weight (B3) (Table 1.0, p. 4).
- Cadmium: batch means from “0.018 ± 0.004” (A2) to “0.067 ± 0.003” mg/kg wet weight (B2) (Table 1.0).
- Chromium: “0.016” to “0.072 ± 0.002” mg/kg wet weight; manganese up to “5.298 ± 0.003” mg/kg (Table 1.0).
- Cited limits: lead 0.30 mg/kg and cadmium 0.10 mg/kg (Codex CXS 193-1995) (Table 1.0).
Methods (brief)
Two grams of paste were digested in a nitric, sulphuric and perchloric acid mix, made up to 50 mL and read by flame AAS (APHA 1995). Solution readings were converted to mg/kg wet weight with a dilution factor of 25. LOD and LOQ are given in ppm of solution; no certified reference material or recovery is reported.
Evidence Fitness
One sample per batch analysed in triplicate, so the SDs are analytical repeatability, not product variability. Flame AAS with no reference material is weak support for values near 0.02 mg/kg. Peer review is unverified, and the printed Zenodo DOI is not registered, so the record carries the journal URL only. For barbecue-sauce this is a proxy: it measures tomato paste, a sauce ingredient, not barbecue sauce, so that page is not linked.