Rodney Hide: Processing - it's another name for tampering

Milk is the superfood of superfoods - and if you drink it straight from the cow, you can taste the sun and smell the grass, too. Photo / Thinkstock

Kiwis like their milk standardised, pasteurised, homogenised and labellised. That way it tastes the same, has no bugs, no thick cream at the top, and you know what's in it.

Milk is special food: it's the only substance on the planet that's only purpose is nourishment.

On milk alone a baby adds billions of brain cells and doubles its weight in six months. Milk is the superfood of superfoods.

But popular columnist Wendyl Nissen recently followed up revelations in this newspaper that the big companies are messing with our daily cows' milk. Fonterra and Goodman Fielder are adding something called permeate. Yuck! It doesn't sound great.

The boss of rival milk supplier Klondyke Fresh described permeate as "green" and "snot-like". Gross. Graeme Brown explained that his competitors added permeate to their milk; but that he did not.

Worse, the big companies aren't telling us how much "green snot" they are tossing in. It is nowhere on the label. Wendyl told the Herald that's "absolutely criminal" and called for changes to food labelling laws.

Horrified, I emailed Fonterra, which produces Anchor milk. It was incredibly helpful in explaining what happens to our milk in those big, shiny processing plants that dot the countryside. I emailed Goodman Fielder, too. It produces Meadow Fresh. It never got back to me.

Fonterra explained that first it standardises its milk. There's a natural variation in milk from cow to cow, herd to herd, season to season. So the milk is finely filtered to separate lactose and minerals from the protein. It's then remixed in standard proportions to ensure consistency across the product over the entire year.

The milk is then separated to give cream and skim milk. The cream is added back to skim milk according to whether it's standard milk being produced or the low fat kind the Government recommends.

The milk is pasteurised to kill any bugs. That's heating to greater than 72C for 15 seconds.

Lastly, the milk is homogenised. That is a mechanical process to break up the fat globules so the cream stays dispersed in the milk. Homogenisation prevents the glug of cream choking the top of the carton. That's it.

Oh, and where does permeate fit in? That's the name for the lactose, vitamins and minerals left when protein is filtered out of milk. It's added back in but to a standard proportion to ensure consistency. That's the process of standardisation.

So Klondyke Fresh, and Aussie dairy companies making plenty of noise about permeate, have "green, snot-like" stuff in their milk. So, too, does mum's milk. It just hasn't been taken out and put back in.

Quite how to explain that on a label is not obvious. Klondyke Fresh could declare its milk "Permeate Free". Or perhaps, "Permeate - Non-Standardised". That could be accurate but hardly appealing.

Food labels are tricky. Still, I find them very helpful. If it has a label, I don't buy it. My test of healthy isn't what's on a label, what doctors say, or what the Minister of Food says is okay. My test is simply: 'Have humans eaten this for thousands of years?' That length of experience is the only real test of whether something is good for us and our children or not.

Our forebears wouldn't recognise much of what's on supermarket shelves as food. Food didn't come in a box. It wasn't processed.

I get my milk from the farm, straight from the cow. It's not standardised, pasteurised nor homogenised. It has no label. It's just milk. I know the farmer. The milk varies with the seasons. The thick cream sits on top. I can taste the sun and I can smell the grass. That's how we have drunk milk for thousands of years.

Those shiny factories? They are very, very impressive. But, for me, they can't improve on two hundred million years of natural selection.

That's how long milk has been nourishing us mammals.