Police are investigating deliberate manipulation of the drinking milk packs around the area that is punctured by the drinking straw.
They have ruled out the issue could be due to technological errors in the manufacturing process and believe the manipulation was later in the supply chain.
The Ministerium der Justiz und für Europa und Verbraucherschutz (MdJEV) in Brandenburg said lab tests are ongoing and urged the public to pay attention to packaging integrity when buying products.
Impacted product is Joe Clever milk drink, strawberry flavour ("Joe Clever" Milchmischgetränk, Geschmacksrichtung Erdbeere) 0.2L with date 4-4-2018 and lot 4021138001307.
It is not known if contaminated goods were placed on the market but Joe Clever participates in the school milk program.
German authorities asked the public to take note of changes in product packaging which may indicate tampering (punctures, opened packages, odour deviations, etc.) and urged consumers not to drink the product in case of doubt.
Potentially impacted states are Bayern, Brandenburg, Bremen, Hamburg, Hessen, Mecklenburg-Vorpommern and Sachsen-Anhalt.