Acetaldehyde is a naturally occurring component of fruits and vegetables and is a residual element of the human metabolic process. The flavouring agent acetaldehyde is formed when PET is heated above 260°C, which occurs during injection moulding. However, this does not cause a health issue, it only leaves a fruity-sweet taste (Stiftung Warentest 5/2013). The mineral water taste limit is 0.02 mg/l and is therefore very low. How much acetaldehyde is released when PET is heated during moulding depends on the quality of the PET. Gerolsteiner only uses the highest quality PET, which contains acetaldehyde blockers, which ensure that acetaldehyde molecules remain bound in the PET and cannot pass into the water.