Anita C,
For most GFSI audits (I can't say all because I'm not familiar with all) it is ok to test once per year.
HOWEVER, here are some exceptions:
Your company requires you to test more than once per year. (Corporate is asking for semi-annual, quarterly, etc.)
You have a customer that requires you to test more than once per year. (Aspirago, Nestle, FoodMaker, etc.) Make sure to read over their requirements.
You fail your own mock recall. Logically as a corrective action is to do another mock recall after you've done your investigation and you've made your corrections to validate your action items did in fact address the root cause of failing the mock recall.
For Agasr point, some customers do require ingredients, packaging, along with WIP or FG. It will be who of you to test a FG along with at least one packaging or ingredient. I've had management fight me on packaging but I never go empty handed into a "fight". I showed management how much Kellogg lost in stock $$$$$ (What management cares about) due to the recall concerning "contaminated packaging" making their product taste like "chemical" and made people sick.
http://www.ewg.org/r...risks-packaging
Bottom line, How prepared do you want to be when the _____ hits the fan, because everyone is going to be looking at you. That is Anita, if you're the one in charge of the system.