There are two related minimum-quantity settings on a Meal Recipe's pricing table (Catering tab), and they're enforced differently:

1. The default catering portion's row shows a Minimum Quantity field (in place of the "Regular Price" column other portions get) — this is the meal-level minimum, and it must be at least 1. It's enforced at checkout: the system adds up how many units of that meal (across every portion size ordered) are in the customer's cart for that catering date, and if the total is below this Minimum Quantity, checkout is blocked with a message showing how many more are needed.
2. Every other portion size row (e.g. "Full Tray" if "Half Tray" is the default) also gets its own Minimum Quantity field. This one is enforced when adding to cart: if a customer enters fewer than that portion's minimum, the ordering page won't add it.
3. Both fields only appear when the Catering module is active.