Michael,
Your primary concern is producing safe food, and to take any precautions within your power to do so. Evaluate the risk posed to the pre-process, in-process, and post-process open & stored product. Physical seperation provides a barrier between unfinished & finished products reducing the chances of cross contamination. One obvious risk that would be present is pest contamination. Obviously, it is imperative that you maintain a pest free warehouse. Reality check: stuff happens. EFK lights are a great way to see that flying insects like to visit food warehouses on from time to time. If you have no physical barrier between your warehouse and process area, an emerging trend that could normally otherwise be contained and controlled inside your warehouse might result in a widespread problem due to the ease of migration. There are other factors that need to be taken into consideration as well such as heat from your processing area. Is your finished stored product now going to be exposed to excessive heat conditions that might affect the safety/quality of the product and/or container? Given the wide usership of this forum, I'm positive that there is more valuable input to add to this conversation..
Refer to the FDA cGMP requirements in 21CFR110.
§110.20 Plants and Grounds: (2)Permit the taking of proper precautions to reduce the potential forcontamination of food, food-contact surfaces, or food-packaging materials with microorganisms,chemicals, filth, or other extraneous material. The potential for contaminationmay be reduced by adequate food safety controls and operating practices oreffective design, including the separation of operations in which contaminationis likely to occur, by one or more of the following means: location, time,partition, air flow, enclosed systems, or other effective means.
§110.93Warehouse and Distribution: Storageand transportation of finished food shall be under conditions that will protectfood against physical, chemical, and microbial contamination as well as againstdeterioration of the food and the container.
Additionally, there are specific clauses in the various GFSI schemes you may want to reference.
(For instance)
BRC Clause4.3.4: (low risk areas)the process flow together with the use of demonstrably effective proceduresshall be in place to minimize the risk of contamination of raw materials,intermediate/semi-processed products, packaging, and finished products.
Clause4.3.5: (high-care areas)there should be physical segregation between these areas and other parts of thesite. Segregation shall take into account the flow of product, nature ofmaterials, equipment, personnel, waste, airflow, air quality and utilizes provision.Where physical barriers are not in place, the site shall have undertaken a fullevaluation of the risks of cross-contamination and alternative effectiveprocess shall be in place to protect products from contamination.
I hope this helps a bit.
-Chris