Between 1929 and 1962 there were no road vehicles for refrigerated goods.
road_Perishables.png
I know and it was somewhat intended to go via road or ship as additional challenge. Also lacking a good vehicle as base.
The only train with some profit in 1940 is the BR01 and at least 15 cars. This requires platforms with 9 tiles.
On many maps, I think it is impossible to open up a food chain under these conditions without going bankrupt.