Garuba et al. (2024) measured eight metals (Pb, Cd, As, Al, Zn, Mn, Fe, Cu) in ten commercial US infant and toddler food products (stages 1-3, seven brands) using QQQ-ICP-MS after microwave acid digestion. Two products exceeded aluminum maximum residue limits (MRL), and three products exceeded zinc MRL, with one beef-gravy product containing 69.5 µg/g Zn — more than 23 times the upper MRL. The rice cereal product (S7) measured 0.102 µg/g arsenic (total, not speciated), essentially at FDA’s action level of 0.1 µg/g for inorganic arsenic in infant rice cereal, though direct comparison is limited because the study did not perform arsenic speciation. No significant relationship between packaging material type and metal concentration was found.
Key numbers
| Sample | Product description | Al (µg/g) | Zn (µg/g) | As (µg/g) | Cd (µg/g) | Pb (µg/g) | Notes |
|---|---|---|---|---|---|---|---|
| S1 | Sweet potato/turkey puree | — | — | — | — | 0.004 | Highest Pb in set |
| S2 | Banana/raspberry puree | 4.09 | — | — | — | — | Al exceeds 1 µg/g/day MRL |
| S3 | Sweet potato/apple puree | 2.50 | — | — | — | — | Al exceeds MRL |
| S6 | Syrup/snack | — | 33.5 | — | — | — | Zn exceeds 2-3 µg/g/day MRL |
| S7 | Rice cereal | — | — | 0.102 | 0.017 | — | As at FDA action level; Cd highest in set |
| S8 | Fruit punch | — | 30.2 | — | — | — | Zn exceeds MRL |
| Beef/gravy (S7 alt.) | Meat-based toddler | — | 69.5 | — | — | — | Zn 23× above MRL |
Average metal concentration across all samples: 0.96 µg/g. ANOVA across sample groups: F(6,24)=2.75, p=0.035. No significant correlation between packaging material (glass, plastic, pouch) and metal levels.
Arsenic note: The paper reports “arsenic” without speciation. The 0.102 µg/g value is total arsenic (tAs). FDA’s 100 ppb action level applies to inorganic arsenic (iAs); iAs is typically a fraction of tAs in rice cereal (commonly 70-80% in rice-based products). Direct comparison to FDA’s iAs action level is not valid without speciation; the authors’ stated comparison is methodologically imprecise.
Zinc note: Zinc is not a heavy metal regulated by HMT&C but is an essential nutrient with upper intake levels. The extreme Zn values in beef/gravy likely reflect added zinc in infant formula-grade supplementation rather than contamination. The authors’ interpretation of Zn exceedances as toxicological concern should be read cautiously; context for the product type is not provided.
Methods (brief)
Instrument: QQQ-ICP-MS (triple-quadrupole). Sample preparation: SRC microwave acid digestion (concentrated HNO3/H2O2). Calibration: external calibration with internal standard correction. No CRM validation mentioned in available text. Arsenic not speciated; reported as total. Sample size: n=10 products across 7 brands; no replication within products stated. Stage classification (1, 2, 3) recorded but analysis primarily by product code.
Implications
Certification: The rice cereal tAs result (0.102 µg/g = 102 ppb) near FDA’s iAs action level (100 ppb iAs) supports continued priority attention to rice-based infant foods. Notably, if iAs is ~75% of this tAs value, the actual iAs would be approximately 77 ppb — below the action level. The lack of speciation limits this study’s direct value for HMT&C Path A threshold work on iAs in infant rice cereal. The aluminum exceedances are potentially notable for HMT&C review, as Al is one of the certified analytes.
Courses: Good example for discussing why arsenic speciation matters in regulatory comparison: a study reporting “arsenic at the FDA action level” without speciation cannot actually confirm a regulatory exceedance. Illustrates measurement gaps in secondary literature.
App: Can contribute tAs values for infant rice cereal and baby food purees, with appropriate caveats about speciation uncertainty. Al data for banana/raspberry and sweet potato/apple products is notable for the app’s Al modeling for stage 1-2 purees.