All the answers have focused on fairly new and recent systems of refrigeration.

所有的回答都把注意力集中在近现代的保鲜系统上。

But in 500 BCE – The yakhchal (meaning "ice pit" in Persian;) an ancient Persian type of refrigerator was invented.

但是在公元前500年，古老波斯的冰箱-yakhchal（在波斯语言中意为冰坑）就已经被发明了。

The structure was formed from a mortar¹ resistant² to heat transmission, in the shape of a dome³.

它是由砂浆构成的，以防止热传递，形状类似于圆顶。

Snow and ice was stored beneath the ground, effectively allowing access to ice even in hot months and allowing for prolonged food preservation⁴.

雪和冰贮藏在地下，能够使冰块在夏季也能够获得，并且有效延长食物保质期。

In Europe and other less developed nations (at the time) spices were used to preserve meat. The most popular being salt since pepper was still expensive and difficult to attain⁵.

在欧洲以及其他少数发达国家（当代）辣椒曾被用于储藏肉类。但是盐会更加的通用，因为辣椒较贵而且不易获得。

1- drying (eg in the sun or via other methods ; eg bresaola, beef jerky)

1.晒干。（比如日晒或者通过其他办法；例如牛肉干）

2- cooling (eg leaving outside the window in the cold)

2.冷却。（例如将食物放置窗外）

3- freezing (eg burying in the snow)

3.冰冻（例如埋在雪里）

4- smoking (eg ham)

4.烟熏（例如火腿）

5- stewing⁶ (note: temperatures above 63 degrees Celsius⁷ are considered adequate for preserving food by today's standards)

5.炖（提示：温度达到63摄氏度相当于当今保鲜食物的标准）

6- canning (eg vienna sausages)

6.罐装（例如维也纳香肠）

7- jellying (eg 'pig head' jelly)

胶凝（例如胶凝猪头）

8- pickling (eg corned beef)

8.腌制（例如腌牛肉）

9- burying in the ground

9.埋于地下。