adding sugar to baby food is not necessarily illegal
there is already legislation which prevents companies from engaging in illegal activities overseas but it's really not efficient since it is so easy to offload any illegal activity to a locally owned company. This is more about human rights abuse and illegal lobbying than product quality control though.
there is nothing forcing multinational corporations to act as a unique global entity when it comes to quality control and any attempt to enforce such legislation would just be quickly sidestepped with local subsidiaries.
Really, the only defense for the locals is the local government. As it should be.