In grocery stores there are basically two ways items get shelved and stocked. For bigger brands (Lays for instance) the truck drivers will actually bring the stock to the aisles and shelve them according to how Lays wants it done. Grocery store never touches it. The other way is for smaller brands, they ship to the grocery store and store employees stock the aisles.

This is why stuff like chips, soft drinks, cereal, and probably even fruit from large companies always seems so organized together.

There are entire industries of analysts and consultants who work with companies like P&G, Heinz, Frito-Lay, Coca-cola who define shelf layout in every store. It's called a planogram. First time a store employee touches a Driscolls clamshell is likely when the cashier scans it.