While I have no connection to this I’ve worker with a few charities and item donations outside of a process that would be used to generate money e.g. goodwill type stores is often highly inefficient to the point of costing the charity more money than the value of the goods.

Food specifically is highly problematic since even canned food go wrong (leave food cans in direct sunlight for a day or two and open them, it won’t be pleasant) these items need to be individually checked and if you need to transport them the cost of transportation alone can often be higher than the value of the goods at your destination.

On a personal note at least in the UK chartities that do pickup goods for donation are highly picky and anything that will not turn a profit will not be picked up or accepted by them as they simply cannot cover the cost of transport and disposale of goods that won’t sell or won’t be of value.

The sad truth is that often the only real thing you can and should donate is cash.