The answer to the question is simple. As little as possible.
The point is, you don’t want to convert your liquid cash to perishable food inventory if you can help it. The more frequently you get deliveries from your suppliers, the less inventory you must keep on hand.
Inventory control is basic “cash management.” Minimizing your inventory increases the liquidity of your restaurant.
Purchases should be tied directly to sales and not storage capacity or some par-stock level based on the maximum usage plus a safety factor.
Remember……. Inventory is Cash.