In countries which still practice wide-scale pickling, curing and fermentation -- stomach cancer rates are still very high.

http://www.reuters.com/article/us-salty-diet-idUSTRE62N4KX20...

While gastric cancer is declining, it is still the most common cancer in Korea. Past studies have yielded conflicting results as to whether a salty diet causes gastric cancer, though most found an association between salt use and gastric cancer.

Here's another piece of information: https://en.wikipedia.org/wiki/Refrigerator

The introduction of Freon in the 1920s expanded the refrigerator market during the 1930s. Home freezers as separate compartments (larger than necessary just for ice cubes) were introduced in 1940.