Decrease of the naturally occurring photo-sensitiser riboflavin in low fat model cheese packed in atmospheric air (○) and in vacuum (●) and in model cheese with 18% fat also packed in atmospheric air (Δ) and in vacuum (▼) after illumination with fluorescent light for a period of 21 days (A) and accumulation of dityrosine (B), lipid hydroperoxides (C) and DMDS (D). Rel. Int.: calculated relatively to external standard curves (ng·mL⁻¹). Bars indicate standard deviations of triplicate for riboflavin, dityrosine and lipid hydroperoxides and duplicate for DMDS. Small squares illustrate low fat cheese in atmospheric air (○) and in vacuum (●) for the first seven days of light exposure.