In 1968, Rongotea 'home economist' - that's housewife to you and me - Norma McCulloch was searching for a better way to avoid freezer burn. Not for herself you understand, but for her silver beet, lamb shanks, cabbages and kings.
The basic theory is that food keeps much better in the freezer if all the air has been sucked out of the surrounding bag first. These days, all trendy foodies with a sous vide device know that, but in the 1970s, this was news.
Previously, 'housewives' had been squeezing the air out of the bags by hand, or even, heaven forbid, sucking it out with a straw - a practice which, according to the admittedly self-interested McCulloch Industries, is 'warned against' by 'Health Authorities' and potentially dangerous.
The freezer vacuum pump was born.