Most smells from food sources are acidic.
Sodium bicarbonate is mildly basic.
This means the two can react together to neutralise the acid and get rid of the smell. For example, Butyric acid which might come from some gone-off food will react with sodium bicarbonate to make sodium butyrate, which doesn't smell, carbon dioxide and water. However, some smells, like those from fish and meat, are basic too so sodium bicarbonate won't get rid of fish smells. This is a stand-alone question which will eventually become integrated into the linked database.