Madan,
I will assume you are not talking about replenishment to the stores or to Distribution centers; which do not directly involve manufacturing at all.
I would like to why would we require a process order and recipe instead of a production order and routing.
That depends on the actual business requirements of the manufacturing group of the client, which your PP expert presumably had already researched before he presented his recommendation to you. Why don't you ask him why he recommended process vs production?
Either or both methods (Production and/or Process) have been successfully used in food manufacturing, depending upon the business requirements.
If you want to research yourself, you can find more info in Best Practices, where both Production and Process manufacturing solutions are described.
http://help.sap.com/bp_cp604/FB_IN/html/index.htm
Also you can refer to SAP help
http://help.sap.com/erp2005_ehp_06/helpdata/EN/db/702f4a63f349c48d938e085de860ca/frameset.htm
Best Regards,
DB49