Ramban on Genesis 41:36/רמב"ן על בראשית מ״א:ל״ו

1AND THE FOOD SHALL SERVE AS A RESERVE FOR THE LAND. Joseph said that the food should be kept in reserve under the charge of Pharaoh’s officers for the needs of the land during the seven years of famine, and they should not be used for other purposes lest the land be consumed by the famine just as the cows in the dream did not die on account of their leanness.