Aluminium in infant foods: Total content, effect of in vitro digestion on bioaccessible fraction and preliminary exposure assessment

Overview

This Journal of Food Composition and Analysis article from UNICAMP (Faculty of Food Engineering) and the Institute of Food Technology (ITAL) Campinas is the primary Brazilian-market Al occurrence survey for infant foods, covering 95 samples across 9 commercial brands in four product categories: salty purees, fruit purees, infant drinks, and petit-suisse. Two distinguishing features: it pairs total-Al measurement by ICP-OES with an optimized in vitro gastrointestinal-digestion protocol to estimate bioaccessibility, and it documents a dramatic 95-fold spread in bioaccessibility (0.5 to 48 percent) across sample compositions, demonstrating that total Al substantially overestimates actual gut absorption for many infant food matrices. The headline numbers: petit-suisse reached 4170 µg/kg, soy-based drink 2860 µg/kg, salty purees containing zucchini-lettuce-lentil-sweet-potato-egg 2760 µg/kg, salty puree containing zucchini-sweet-potato-lettuce-beans-egg-yolk 2310 µg/kg. Consumption of three portions per day of soy-based drink could reach the PTWI for Al.

Key numbers

Highest total Al concentrations by product category (µg/kg)

Bioaccessibility (in vitro gastrointestinal digestion)

Bioaccessibility spans 0.5 to 48 percent (96-fold range), driven by sample matrix composition: high-cellulose matrices (purees with fibrous vegetables) and high-protein dairy (skim-milk petit-suisse) reduce bioaccessibility through Al-cellulose and Al-protein binding; high-polyphenol or low-fiber matrices (cereal drink, whole-milk petit-suisse) increase it. Soy matrices show divergent results across brands (1.4 percent F vs 37.8 percent G), likely reflecting differential fat content and protein hydrolysis state.

Exposure assessment summary

Consumption of three portions per day of soy-based drink delivers Al at a substantial fraction of the EFSA TWI (1 mg/kg b.w./week) and could reach 100 percent of PTWI for infants. Petit-suisse and high-Al milk drinks similarly approach the TWI ceiling at typical consumption frequencies for Brazilian infants. Fruit purees from brand B (handmade-gourmet positioning) carry substantially higher Al than industrial-brand counterparts (brands A and C) at similar composition, suggesting handmade production involves more Al contamination through utensils, storage, and raw-material handling.

Methods (brief)

95 infant food samples obtained from retail in Campinas, SP, Brazil, across 9 commercial brands (industrial and handmade-gourmet). Brand B is handmade-gourmet; A, C, D-I industrial. Categories: 43 salty purees, 15 fruit purees, 28 infant drinks (including soy-based drinks), and 9 petit-suisse samples. Total Al by ICP-OES after oxidative microwave digestion in HNO3 + H2O2. LOD 49 µg/kg (purees) or 16 µg/kg (drinks); LOQ 92 µg/kg (purees) or 30 µg/kg (drinks). Accuracy validated on SRM 1548a Typical Diet and NRC EGGS Egg Power CRMs (87-97% recovery). Bioaccessibility by optimized in vitro gastrointestinal digestion (Minekus et al. 2014 protocol with INFOGEST-style salivary, gastric, and intestinal phases), n=3 per sample.

Implications

• Certification: HMTc Al-threshold development for infant food categories must distinguish total Al from bioaccessible Al. A high-total-Al but low-bioaccessibility product (apple-and-plum puree at 0.5 percent) presents different risk than a high-total-Al high-bioaccessibility product (cereal milk drink at 48 percent). The CC candidate framework should track both, particularly for infant drinks and petit-suisse subcategories. Handmade-positioning products (brand B) consistently higher than industrial counterparts is a market-segmentation signal worth flagging.
• Microbiome / clinical: Bioaccessibility variability indicates that Al-microbiome interactions are dose-modulated in unpredictable ways across infant diet items; high-cellulose plant-puree foods reduce gut Al exposure even when total Al is high.
• App: Per-product bioaccessibility correction factor is a strong app input. Default to 10-15 percent for milk-based mixed products, 1-5 percent for high-fiber plant purees, 30-48 percent for cereal-and-milk drinks.
• Courses: Standard reference for the “total Al vs bioaccessible Al” methodology question — a foundational distinction for infant exposure assessment that the regulatory framework does not capture.

Wiki pages updated on ingest

• Aluminum
• Fruit Purees
• Non-Root Vegetable Purees
• Root-Vegetable Purees
• Mixed Meals, Non-Rice
• Infant Formula, RTF Liquid (Soy-Based)
• Infant And Child Foods Master

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