Overview
Terbeche and colleagues studied metal migration from cans and aluminium cookware into food. They aged single cans of tuna in tomato sauce, sardines in tomato sauce and double concentrated tomato, either at 55 °C or by real storage, then measured aluminium, iron, lead, chromium, nickel and tin by AAS after a hydrochloric acid leach. They also measured aluminium in tuna cooked in foil or trays. Most metals rose with aging.
Key numbers
- Canned tuna in tomato sauce, lead: 0.0101 mg/kg recent can, 0.0153 mg/kg after 47 days at 55 °C (Table 3, p. 635).
- Canned sardines in tomato sauce, lead: 0.0571 mg/kg control, 0.0874 mg/kg after 19 days at 55 °C; tin 0.0287 to 0.0801 mg/kg (Table 4, p. 636).
- Tuna cooked in aluminium foil over a flame: aluminium 0.0753 mg/kg, against 0.0268 mg/kg on a tray in an oven (Table 7, p. 637).
Methods (brief)
Five to 10 g of can contents was stirred in 1 M hydrochloric acid at 80 °C for one hour, filtered and read by AAS. This is a partial leach, not a total digestion. Can steel and foil were characterized by XRF and EDS. There is one can per condition, and no detection limit, reference material or recovery is reported.
Evidence Fitness
A small migration experiment, not a market survey. The tomato-concentrate table (Table 6) repeats the sardine table (Table 4) value for value, so the tomato data cannot be relied on and are flagged. Iron below 0.3 mg/kg and other very low values suggest incomplete extraction. Useful mainly as a direction-of-effect signal for can aging and aluminium cookware. Tomato concentrate is a proxy for barbecue-sauce, pasta-sauce and tomato-soup; those pages are not linked.