I'm looking for some benchmarking on org structures for food companies primarily around food safety, food protection, and quality. Do they report up to the same person?  Where do they report up through? How do you differentiate them?  

Typically it will be a VP of Operations or COO.  

I'd suggest you do an internal exercise before thinking of benchmarking.
What you need to look for is conflict of interest with the work the functions defined are doing.
Example, the food safety team can never report to the manufacturing leadership as long as the food safety metrics are not in the incentives of that management/department.
So it is mainly defined by how the current incentive structure creates potential conflict of interests within the organisation.
Even before anchoring the food safety dept, I'd clear up the incentive structure if it was incorrectly defined before.
Hope, this helps.
Benchmarking is only good if you know exactly what you are looking for already, as others can do these things differently but you won't know why (unless they tell you the whole setup and thought process behind, which is rare....or you pay for a lot of consultancy fees, but it can be worthy if the current state is bad).