In a nutshell.
Firstly you must make sure your raw materials are suitable and have undergone migration testing for the end customers (myriad range) of products and processes (and countries of consumption). Then you need to ensure you have good GMP and chemical controls in place at your manufacturing to ensure you do not taint or contaimate packaging and you also need to conduct your own finished product migration testing. This migration testing should be undertaken perhaps every 3-5 years or if your process changes siginificantly or if the law changes. It costs a fortune and is very complicated, I recommend contacting a competent laboratory to assist you in developing a program.
Regards,
Simon