Stability of powdered infant formula during secondary shelf-life and domestic practices

Powdered infant formula (PIF) and lactose-free PIF during secondary shelf-life (SSL) and under domesticpractices was investigated to verify their stability up to the expiration date and under the label in-structions for milk reconstitution. Particular attention was given to variations in Maillard reaction andlipid peroxidation products identified and quantified by HS-SPME-GC-MS. Two types of PIF: Type A basedon bovine milk and Type B a lactose-free product based on glucose syrup were analysed. The PIF wereanalysed at regular time intervals beyond the labelled expiration date after opening, and reconstitutedusing water at 70C, 80C and 90C. A large number of volatile compounds were identified and sig-nificant statistically differences resulted during SSL and water temperature used for reconstitution thatwere correlated to the PIF composition. The study showed that water temperature for reconstitution ofsamples and the SSL has to be adapted to PIF composition.