I work in a supermarket where I am required to pack even haraam tinned products.

Answer

It is not permissible to handle the haraam products. Continue with your present work, and make dua for a better avenue of Rizq to open up for you. Be on the lookout for alternative work where you will not have to contend with haraam products and issues. May Allah Ta'ala open the ways of Halaal Rizq for you.