You can set the availability of products on the EPOS to be based on the stock levels tracked by the system. Setting this will mark products as out of stock automatically when the stock falls to zero (or below).
Note: setting availability based on stock will not prevent someone from putting through a sale of more than the remaining stock, it will only set the product to be out of stock after a sale that uses the last of the stock is put through. If you want to prevent sales being put through that would take an item out of stock you should set a quick stock value on the product.
You can set stock based availability on a product by pressing and holding on the button on the EPOS, then pressing 'Availability' and 'Based on stock'.
You can also set it on the back office on the advanced tab of the product.
Note: You would need to do this if you want to set an ingredient to be based on stock, as an ingredient doesn't have a button on the EPOS.
If you would like items with recipes to be marked out of stock when some or all of their ingredients stock levels fall to zero, you will need to set 'Include ingredients in stock based availability' to 'Y' in the stock tab of the set up module on the back office. Then set any of the ingredients that you would like to trigger a product out of stock to have an availability of 'based on stock'.
In this way you can select which ingredients will cause products to be marked out of stock, and which will not (for example those that can be easily substituted or are hard to track.
You can not directly set an item with a recipe to have an availability based on stock, as it doesn't have a stock value (only its ingredients do), but you can set a quick stock value on a product with a recipe.