A Comparative Study on Presence of Heavy Metals Lead and Cadmium in Tomato Ketchups used by Street Vendors of Delhi NCR

Overview

This short research article reports Pb and Cd concentrations in 12 tomato ketchup samples collected from street food vendors across four locales in the Delhi NCR region of India. Lead was reported in all four locale summaries, with mean concentrations in Delhi (0.183 ppm), Noida (0.096 ppm), and Faridabad (0.089 ppm) exceeding the FAO/WHO Codex limit of 0.05 mg/kg; only Gurugram samples (0.031 ppm mean) fell below. Cadmium was below detectable limit in all 12 samples.

Key numbers

Pb concentrations by locale (mg/kg, wet weight, mean ± SD):

• Delhi: 0.183 ± 0.11 (range 0.10–0.311)
• Noida: 0.096 ± 0.08 (range BDL–0.148)
• Faridabad: 0.089 ± 0.15 (range BDL–0.266)
• Gurugram: 0.031 ± 0.05 (range BDL–0.093)

Cd: BDL in all 12 samples across all four locales.

FAO/WHO Codex limit for Pb in tomato products: 0.05 mg/kg (at time of study). ANOVA across locales: not significant (p = 0.42).

n = 12 samples (3 per locale). Method: Atomic Absorption Spectrophotometry (AAS). No LOD/LOQ values reported.

Methods (brief)

Samples were collected in sterilised sealed glass containers from street vendors and transported to the laboratory within two days. Analysis was by AAS; sample preparation and digestion chemistry are not specified. Statistical analysis was by one-way ANOVA in Microsoft Excel. No LOD or LOQ values are specified, and BDL is not numerically defined; this limits quantitative utility. The study does not distinguish branded vs. unbranded ketchup or report processing/storage conditions.

Implications

Certification: The Delhi, Noida, and Faridabad mean Pb values exceed the Codex limit; this is a small-n study in an informal market setting in India and carries B-tier weight. It provides contextual evidence that tomato ketchup can concentrate Pb above regulatory thresholds depending on sourcing and handling, but does not anchor HMT&C threshold setting on its own.

Courses: Useful illustration of urban-market lead burden in processed condiments; suitable for modules on informal supply-chain contamination pathways.

App: Contributes context for ketchup/tomato sauce as a Pb-relevant condiment category in informal-market settings; Cd signal here is null (BDL), consistent with the study’s tomato-ketchup matrix.

Wiki pages updated on ingest

• Condiments (hot sauce, soy sauce, mustard, ketchup, mayonnaise, salsa)
• Tomato
• Ketchup

Verification notes

• 2026-05-18 Codex merge-enhance against the source PDF in condiment_papers: corrected raw_path, changed unsupported license: "CC BY" to unknown because the PDF states open access but does not state a Creative Commons license, and replaced missing [[products/ketchup]] with live product route [[products/condiments-general]].
• Numerical table checked against Table 1 and Table 2: Pb means/ranges for Delhi, Gurugram, Faridabad, and Noida match the source; Cd is BDL in all four locales; ANOVA p = 0.42 matches Table 1.
• Cross-vendor audit (Codex, 2026-05-18) retained matrices: [ketchup] as a source-specific matrix label because the common matrices vocabulary does not include a clean tomato-ketchup or condiment matrix; routing is carried by live [[ingredients/ketchup]] and [[products/condiments-general]] links.
• 2026-05-28 Claude Opus 4.7 merge-enhance against the source PDF: (1) replaced placeholder raw_handle: manual-fetch-kimi with the MFK_-prefixed slug MFK_a-comparative-study-on-presence-of-heavy-metals-le per the manual-fetch handle convention; (2) added raw_sha256 computed from the local PDF; (3) added access_url from the DOI; (4) restored license: "CC BY-NC" after re-reading the source — the Creative Commons BY-NC mark is rendered as an icon in the page-1 footer below the “Copyright (c) 2020: Advanced Research Publications” line, which the 2026-05-18 text-only pass missed. Body content was unchanged because the 2026-05-18 numerical table check still holds against Tables 1 and 2.

Update history

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