This sign was posted at the entrance of a Prisma brand supermarket in Espoo, Finland. The same text is written in the "standard Finnish triplet" of Finnish, Swedish and English, in that order and with the Finnish text with perhaps a slightly larger font. (For once the different languages seem to convey the same message!) Below them we have an icon of shoes with a red cross symbolising "No!", and at the bottom the shop logo.
What caught my attention here was the juxtaposition between the text talking about allowing something, while the image component is forbidding something. Even though the text discusses on allowing only foodstuff, I get the feeling that the shoes are not symbolising here all non-foodstuff items, but rather all non-dirty items. I would not feel that it would be wrong to place a shopping list or a book to the cart, but I wouldn't lift a dog or a used football there. Perhaps this arises from the fact that the shoes do not look pristine here, "fresh from the package", but rather already worn?
This sign is clearly one where part of the curiosity arises from me being uncertain how universal my personal interpretation would be.
As a final note, I also find the language used here curious. They do not state that "[...] are to be placed in [...]" but rather that "[...] are placed in [...]". The statement feels less of a guidance and more of an absolute statement. This seems to persist across all three languages.