Not hygienic at all
The batch that I recently bought came in bulged tin, and the lid makes a clicking sound when being pushed down. I contacted Zooplus, which in turns enquired the manufacturer for me, claimed that this is not a problem as a vacuum was not created in the tin. How is this even acceptable. No wonder why it gave my kittens diarrhea. Avoid at all cost!!! Would have given zero star if I could!