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 domestic practices was investigated to verify their stability up to the expiration date and under the label instructions for milk reconstitution. Particular attention was given to variations in Maillard reaction and lipid 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 were analysed at regular time intervals beyond the labelled expiration date after opening, and reconstituted using water at 70C, 80C and 90C. A large number of volatile compounds were identified and significant statistically differences resulted during SSL and water temperature used for reconstitution that were correlated to the PIF composition. The study showed that water temperature for reconstitution of samples and the SSL has to be adapted to PIF composition.