They can be on store shelves for a long period of time, and that has to do with the economics of food, especially food available to the poor, which we'll discuss later.

因此可以在商品货架上销售很长一段时间,这也与食物的经济学价值有关,特别这类食物穷人也买得起,这个我们以后会讨论

耶鲁公开课 - 关于食物的心理学、生物学和政治学课程节选