What do they actually do to our milk in the factory?

By: "Farm Tender" News
Regenerative Ag & Carbon Farming News
Jul 30, 2019
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By Glen Herud - Founder Happy Cow Milk Co. NZ

The milk we drink today is the result of technological progress over the past 30 years. That means milk today is very different from what we called milk 30 years ago.

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Cows generally produce milk with 3.7% fat and 3.5% protein. Jersey cows produce higher fat content, while Friesians have higher protein percentage. A cow at the end of her lactation will have a higher fat concentration in their milk too.

I ran into trouble one year when quite by chance all my “in-milk” cows were Jerseys in their last month of lactation. The result was our milk had 5.5% fat content. Our cafe customers were calling me complaining that the milk wouldn't stretch or froth properly.

Baristas were perplexed when I told them a quick fix was to use 60% milk & 40% water in their jugs. Effectively diluting the fat content back to 3.3%.

To solve this fluctuating fat content problem, factories in the old days introduced the practice of standardisation.

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Milk would go through a cream separator that uses centrifugal force to separate the heaver milk from the lighter cream. A simple calculation would ensure the correct amount of cream would be added back into the skim milk in order to give it the desired fat content.

Cream separating from milk is a natural process that milk does by itself anyway. The invention of the cream separator simply speed this process up a bit & the milk was not noticeably different.

Then one day, somebody, somewhere, for some unknown reason decided that consumers don’t like the cream sitting in the top of their milk bottle. So the process of Homogenisation was introduced.

Homogenisation is the process of forcing milk at high velocity & under high pressure through a very small hole, 0.1mm in diameter to be precise. This causes each fat globule to break into lots of little fat globules. These small globules stay suspended in the milk and do not rise to the top.

The advent of Homogenisation is the point when we really started to get quite invasive with our milk and started modifying its constituents. But the next invention goes another step further.

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The invention of ultrafiltration uses membrane filters & enables factories to separate milk components down to the molecular & ionic levels. This is where the term “permeate” comes form. The permeate is what passes through the filter and is basically white water. The retentate is what is retained & does not pass through the filter. The retentate is the valuable bit & contains all the solids including fat, protein etc.

In the past, standardisation was the process explained earlier using a cream separator & adding back the cream into skim milk.

Today, standardisation means the milk is deconstructed down to the molecular level. Some retentate (fat, protein & solids) is added back to the permeate (white water). This allows factories to standardise both the fat and the protein.

The levels of protein and fat are regulated in the NZ/AU Food Standards. Whole milk must have at least 3.2% fat and 3.0% protein. If you look at your milk bottle, you’ll find your milk has exactly those minimum percentages.

But as we know cows actually produce on average 3.7% fat & 3.5% protein.

Ultrafiltration allows dairy businesses to pocket the value of the 0.5% fat & 0.5% protein which is not included in your bottle of milk.

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Faced with unhappy baristas with overly creamy, non-streachy & unfrothy milk. I had to find a way to keep our fat content consistent. I certainly didn’t have the money to add a cream separator to our little factory.

During one milking, the ghost of Ernst Rutherford appeared to me and uttered the words “Glen, you don’t have the money, so you have to think”.

At that moment, the process of in paddock standardisation came to me. I’d like to think this innovation is as profound as splitting the atom but its simply just the way we did things 30 years ago.

We use a small herd of Jersey/Friesian cross cows so we don’t get big fluctuations in fat & protein percentages. We feed them just grass and the cows calve 365 days a year. The result is an even distribution of cows at different lactation stages, which results in a very consistent fat & protein content without all the modern machines.

To me, the best technological progress will enable us to go back in time, to the way milk & dairy was 30 years ago.