Parle Agro — appy fizz expired before its expiry date

Address: B-sector, P1-Line,Cheeta Camp,Trombay, Mumbai City, Maharashtra, 400088

Appy Fizz taste is very bad seems it is expired but expiry date is valid (i.e product is not expired).
My sister suffering from food poisoning after drinking Appy Fizz.
We went to the retailer and told about this and demand for refund the amount, but he says I m not responsible for this. Whatever it is you can directly complain to the company site or call to consumer care.
So, Who is responsible for this ? and Who will pay all the amount?