He who buys food-rain should not sell it until he has taken possession of it. Ibn Abbas (Allah be pleased with them) said: I regard everything like food (so far as this principle is concerned). (Using translation from Muslim 1525c)
قَالَ رَسُولُ اللهِ ﷺ «مَنِ ابْتَاعَ طَعَامًا فَلَا يَبِعْهُ حَتَّى يَقْبِضَهُ» قَالَ ابْنُ عَبَّاسٍ فَأَحْسَبُ أَنَّ كُلَّ شَيْءٍ بِمَنْزِلَةِ الطَّعَامِ