These ten products all had AA content higher than the 10 micrograms/litre limit set by the mineral water industry itself. The limit was established in the knowledge that an unpleasant fruity aroma becomes apparent in still and medium sparkling mineral water at higher AA levels.

Nine out of 19 own-brand waters from discount stores tested were above the limit. Stiftung Warentest states that single-trip PET bottles are favoured by discount retail store chains such as Aldi, Edeka, Kaufland and Lidl.

Many of them keep production cost of these bottles low by having them produced without the PET containing AA blocker additives, the association added.

At the time of the test, there were however three of the discounters’ low cost mineral waters that did not have a fruity aroma. These were Claudius Mineralwasser from Aldi Nord, Heinberg Quelle from Edeka und Clausbach-Brunnen from Kaufland.

Stiftung Warentest explained that the more expensive producer brands such as Apollinaris and Gerolsteiner sold in other types of retail outlet are filled mainly in multi-trip PET bottles for which PET containing AA blocker additive is used.

The situation is already changing however, as the Aldi Nord discount store group, for example, announced that it would be using PET bottles containing an AA blocker as from July 2008 for its Brandenburger Urstromquelle mineral water product.