Monday, December 29, 2014

Is Raw Milk Safe? Some Pasteurisation Facts. Why I Won't Sell Raw Milk & What To Look For In A Raw Milk Supplier

Tragically a child in Australia has died as a result of drinking contaminated raw milk. 

So the raw milk vs pasteurised milk debate begins again. The comments on this article from June this year show the diverse opinions.

I grew up drinking raw milk from the vat. We looked long and hard at selling raw milk. We looked at the issues and decided that raw milk was not for us. I'll explain why.

Is raw milk safe or not? 

The quick answer is, it can be safe, but it can turn bad very quickly.

First up, what is pasteurisation?

We boil contaminated water to kill bugs. Pasteurisation is simply heating the milk up to kill any bad bugs that may be present. 

It's not just milk that we pasteurise either, most freshly squeezed orange juice is pasteurised, just as egg products are too. We don't seem to have debates about those products.

The pasteurisation process is a combination of temperature and holding time. For example you can heat milk to 60 degrees and hold it there for 30 minutes (called batch or low temp long time) or you could heat it to 72 degrees and hold it there for 15 seconds (called high temp short time HTST).

I've chosen a batch system where we heat the milk to 65.1 degrees and hold it there for 10 minutes.

Does pasteurisation affect the milk?

Yes & no.
Pasteurisation does not change the nutritional value of the milk such as fat, protein content etc. 
But it does affect other aspects of the milk. The heat treatment process kills any "bad bugs" that are in the milk & it also kills any so called "good bugs" that are in the milk too.

To check that milk has been pasteurised. We conduct a test called the Alkaline Phosphatase test. This test is looking for the Alkaline Phosphatase enzyme. If milk is properly pasteurised, then alkaline phosphatase is inactivated. If it is detected then the milk has not been pasteurised.

This indicates that the heat treatment is affecting some aspects of the milk. 

Does it matter? 

There seems to be very little or no scientific evidence showing any benefit to drinking raw milk. But raw milk proponents will give examples of a friend or a family member who had an ailment that disappeared after swapping to raw milk. There's even books about how raw milk can cure autism. It hasn't made one bit of difference with my autistic son!

Either way both opinions will continue to exist.

I couldn't see any real evidence other than some anecdotal evidence that raw milk is better for you and that the pasteurisation process adversely affects the milk.

People are confused about what happens to milk

What I did discover in my customer & market research, was that the public don't understand what pasteurisation, homogenisation and standardisation is.

People try raw milk and they think "wow" that tastes so different to the supermarket milk. They conclude that it must be because it is raw milk. 

The fact is, you can take milk from the same batch, pasteurise half of it & conduct a taste test. The pasteurised milk will have exactly the same amount of cream on top and taste exactly the same as the raw milk. 

People can't tell the difference.

What people can tell the difference of, is if the milk has been homogenised & standardised. It's those two processes that alter the look, texture & taste of the milk.

There is a perception that you can only get full cream milk, straight from the cow, just like the old days. If it is raw milk. People think the pasteurisation process is what removes the cream or "waters it down". 

I couldn't see any rock solid reason to sell raw milk. But I could see potential risks to selling raw milk.

How to ensure raw milk is safe

The food scientists will say that you simply cannot ensure that raw milk is safe. I think thats being a bit over the top. 

After all I spent my whole childhood and teen years drinking milk from the cowshed vat. I also did a fair bit of milking and I remember accidentally dropping the teat cups into a fresh wet cow pat every once and a while and watching as the cups sucked it straight into the milk line. I survived.

Simply put, raw milk can be safe if it is produced to high standards and consumed in short order.

There are a number of people who produce and sell raw milk properly. They are registered with the ministry for primary industries and have testing regimes & procedures in place.

What makes raw milk unsafe? 

The same things that could make pasteurised milk unsafe. The obvious issues are big bad bugs like, Salmonella, E.coli, B. cereus, Listeria & Staph Aureus. Pasteurisation will kill or deplete these bugs if they are present.

If any of these organisms are found in raw or pasteurised milk, you would have to ask serious questions about the practices of the operator.

The other things to consider are Coliform levels (fecal bacteria) , Aerobic plate counts (bacteria) & somatic cell count (measure of mastitis or infection in the udder).

The people who sell raw milk properly have Coliform, APC & SCC levels well below that of the average dairy farmer. 

If raw milk is produced to high hygiene standards & has very low bacteria levels in it & it is kept at below 4 degrees C, then it will likely be safe. 

Problems arise when the temperature is elevated above 4 degrees. Bacteria reproduce when it gets warm. If a bottle is left on the bench at room temperature, the bacteria can rapidly reproduce. Its possible that a bad bug is present, but in such low levels that it is not a problem. But it could reproduce to levels that then become a problem.

This applies to pasteurised milk too, but the difference is pasteurised milk will have lower bacteria levels in it and the bad bugs are heat sensitive and will have been killed. So any bacteria that are multiplying will not be harmful. 

One of the reasons the New Zealand regulations only allow raw milk to be sold from the farm gate, is that transport from the farm and storage at a separate location, increase the risk that the milk is not kept chilled and it also extends the time in which the milk will be consumed.
Long supply chains and raw milk are not an ideal mix.

What to look for in a raw milk supplier

If you want to buy raw milk in New Zealand then there are a number of farmers doing it. You want to buy milk from someone who has impeccable hygiene in the cowshed & healthy cows.

The things to look for are:

  • First of all look for their approval certificate from MPI. If they don't have one it means their systems have not been approved by MPI. They are breaking the law. Don't buy.

  • How tidy and clean are the surroundings? Is there rubbish laying around? Is the cowshed clean, are the railings clean, has the yard been hosed clean, are the teat cups clean?

  • Ask to see the old milk filters. The milk filter catches any foreign matter. If its green, that shows that cow poos on the cows teats have mixed with the milk. In my experience most commercial dairies will have green milk filters at the end of milking.

  • Does the farmer have a large herd that supplies a milk company like Fonterra or is 100% of the milk going to be sold to the public as raw milk? This is important because if a farmer is milking 400 cows and simply diverts some of the milk to sell to the public. It is unlikely that they are following the required hygiene requirements for safe raw milk. They won't be washing & disinfecting the teats of all 400 cows.

  • Ask about their milk testing regime, what are the bacteria levels that they aim for? 

My Conclusion

People love real milk that has not been heavily processed. Milk that has been standardised & homogenised is very different from real milk.

Many people jump on the raw milk bandwagon simply because they like the taste of real milk. Most of these people will be quite happy to drink real milk that has been pasteurised.

I don't think there is any advantage in drinking raw milk over "real milk" that has only been pasteurised.

To me any advantage (if any) of raw milk is outweighed by the risks.

I'm happy for people to drink raw milk if they want to, as people should be free to do as they please. 
For this reason I support the current regulations that allow people to buy it from the farm gate. This allows people who really believe in raw milk to access it. But they have to be really keen to drive to the farm and collect it.

I'm happy for the public health system to treat you if you get sick too. After all the tax payer funds the treatment of people doing silly things on motocross bikes etc.

But I do have a problem with people feeding it to their young children. They are not able to fight off an infection as well as an adult.


  1. This is a tragic event, however, the product was not sold to be consumed with your weetbix or milo. We occasionally drink raw with our two year old daughter; however, we do purchase our milk from recognised organic raw milk suppliers or Arran farms based near Feilding. I believe the cleaning of the "raw milk" herd is right up there and the farmers know the risk involved of selling 'bad' milk to the public.
    I find it interesting the MPI will be releasing a report later this year determining the safety of selling raw milk direct to the public, I believe the big boys like fonterra will be heavily involved in this decision. Village Milk to name but a few raw milk suppliers will be wondering where that leaves them.
    Common sense Glen, is the best measure when it come to drinking milk. I notice in the staffroom, milk can left out on the bench for at least 30 minutes (I tend to put it back in the fridge after a discrete sniff test) whereas the raw stuff is used and immediately put back in the fridge when at home.
    I'm an advocate for raw milk because it gives people choice about their health. You should read up about A2 milk and you may change your perception about the 'real' benefits of raw milk.

    I hope to read in a few weeks that you've finally entered the market yourself!


  2. Hi Bert
    Thanks for the comment.
    I think people should be able to buy raw milk if they want to. Arran Farm & Village milk seem to be really good operators.

    I think the current regulations allowing raw milk sold from the farm gate is a good balance.

    We'll be breeding from only A2 cows, with the view to only have A2 milk.


  3. I have written an article about pasteurized milk and it worth mentioning it. PLease check it here and let me know what do you think. All the best, Glen, keep writing I enjoy your blog.

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  5. In present day I believe that pasteurized milk is safe compared to raw milk. I will put one point here is that percentage of pesticides we are using to feed the cow's and indirectly we are consuming pesticides and that may effect our health.
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