I came across this piece of film with a family connection. Watch from 3:08. It shows the Pukekohe Dehydration Factory that supplied not only dehydrated vegetables but quick-frozen and canning vegetables as well, to be transported to US troops in the Pacific. By 1945 the factory was supplying 1.5 million pounds of vegetables to the US forces a week.
The link - my family came to Bombay, about six miles from Pukekohe, in 1956 when my father was fifteen. They started market gardening not long after that. He told me about supplying peas to the "Dehy" in the 60's before he got out of market gardening and went into trucking. The factory operated until about 1975.
