A so-called “backscratching” principle was rather popular between factories and collective farms. So they preserved different vegetables for winter.

这段意思不对吧，原文是说这些工厂农场什么的都知道互相帮助，所以各单位冬天腌的菜都不同然后大家换着吃。

youdao

Vegetables, fruit, nuts and other edible parts of plants, prepared or preserved by vinegar or acetic acid.

蔬菜、水果、坚果及植物的其他食用部分，用醋或醋酸制作或保藏的。

youdao

Root vegetables were also preserved in brine after they had been parboiled.

根菜也保存在盐水后，他们被蒸。

youdao

It was a sultry September, and a snack of dan dan noodles seasoned with salty preserved vegetables, perky Sichuan peppercorns and chili oil kept me alert in the intense humidity.

WSJ: Lust for Spice: Sichuan Peppercorn Recipes

For the winter months, he says he will serve preserved fruits and vegetables prepared in the restaurant.

FORBES: A French Chef Looks To Break The Rules And Change The World With New Restaurant

In 1990, the company began producing the preserved fruits and vegetables used to make the traditional Lunar New Year dish of Yu Sheng.

CNN: Sin Hwa Dee facts