What is the difference between fresh and long shelf life milk?

When buying milk in the supermarket, there is a wide choice. Two important types are fresh milk, that has a short shelf life and needs to be stored in the fridge, and long shelf life milk, that can be stored at room temperature. Different countries prefer different types of milk. Why does this difference exist? And does the type of milk make a difference to its quality and nutritional value?

The main difference between these types of milk is the temperature used during processing. For fresh milk, a mild pasteurisation is used, with temperatures around 72°C. This way, pathogenic bacteria are killed, making the product safe for consumption. Bacteria that can spoil the milk are however not killed, making it necessary to store the milk in the fridge. For long shelf life, ultra-high temperature (UHT) treatment is commonly applied, with very high temperatures (130-140°C) for seconds. This treatment kills all bacteria that may cause spoilage. This milk has a very long shelf life and can be stored at room temperature, because bacteria can no longer spoil the product. The advantage of UHT milk is that it does not require cooled transport/storage, making it easier for dairy companies & retailers to work with.

But why then do we not just sterilise all milk, if it makes life easier? This is mainly due to taste. Pasteurisation has only a very limited effect on taste compared to raw milk. UHT sterilisation, on the other hand, causes the formation of a specific flavour due to the high temperature used.

And what then about the nutritional value? The main nutrients in milk (protein, fat, lactose, minerals) are not harmed by UHT sterilization, keeping them intact. For some vitamins, small reductions (max 10%) can occur. So the nutritional quality is essentially the same. Only when sterilisation is more intense, which can be noticed through a brown colour, the nutritional value is lower, due to damage to the protein (essential amino acids).

I earlier wrote about raw milk (link) and the immunoprotective components in them. Those components are more harmed by UHT sterilisation than pasteurisation, although health benefits for consuming these components is currently very limited, especially in adults.

Summarizing, the main differentiation between fresh & UHT milk would be on taste and shelf life, whereas nutritionally these products are virtually identical.

Kasper Hettinga, August 2017

What type of milk does a toddler need, if any?

Breastfeeding is the best choice for feeding a baby and toddler, exclusive for the first 6 months and combined with other foods up to 2 years. However, the majority of children will not be breastfed that long, especially after the first year of life. Then, the question is what the best alternative would be. Breast milk provides high quality protein, calcium, and several B vitamins. These nutrients are also provided by regular milk. Therefore, 2 cups of milk (300 ml) are advised for young children. This milk provides these necessary nutrients to the developing child. Completely skipping milk from the diet is therefore unwise. Besides regular milk, there are several popular alternatives, toddler milk, goat milk, or plant-based alternatives.

A product that has gained interest in recent years is toddler milk, also called follow-up formula or growing up milk. This basically is milk enriched with several nutrients. Milk does not sufficiently provide several of these nutrients (e.g. iron, vitamin D, essential fatty acids). But as milk is not the only source of nutrients for toddlers, this is not a problem. A varied, healthy diet and separate vitamin D supplements should be sufficient to provide the necessary nutrients. So although toddler milk will provide many nutrients to the young child, this product is not necessary assuming a varied & healthy diet including regular milk.

Some children can not tolerate bovine milk, for example due to lactose intolerance or cow’s milk allergy. Parents may be tempted to try milk of other mammals. Especially goat milk is drawing a lot of interest recently. However, goat milk contains the same amount of lactose compared to bovine milk. Also when it comes to proteins, goat milk is very similar to bovine milk. Therefore, children with lactose intolerance can’t tolerate goat milk, as do the far majority of children with cow’s milk allergy. Goat milk is thus seldom a solution if bovine milk can’t be consumed.

Another group of alternatives for cow’s milk are plant based product like soy drink. In case of cow’s milk intolerance or allergy, soy drink can usually be consumed without problems. When choosing a soy product for a toddler, several aspects are important. First, the product should be enriched with the same nutrients as regular milk (calcium, B vitamins) because otherwise deficiencies may arise. Second, a product without added sugar is preferred to limit sugar intake. Even when choosing such a product, the protein quality of a soy drink will still be lower than of regular milk.

In conclusion, milk is an important source of nutrients in a toddler’s diet. Special toddler’s milk or goat milk have no apparent benefit over regular bovine milk. Plant based products like enriched, sugar-free soy drink can be a good alternative if bovine milk is not tolerated, although it’s not nutritionally identical.

Kasper Hettinga, April 2017

Is milk full of hormones?

After discussing the social media story on antibiotics earlier, I now want to move on to another component that is often thought to be present in milk at harmful levels: hormones.

First of all, milk does contain hormones. All animals (and humans, if you want to see that as a separate category) make hormones and they are present in all our tissues and secretions. So all our animal-derived food (and also breast milk) contains hormones. For milk, the interest is in two groups of hormones: growth hormones and sex hormones.

When it comes to growth hormones, it depends on where you live. In Europe there is a general ban on growth hormones (BST, IGF-1) in animal husbandry. Still, low levels due to natural presence of these hormones occurs in milk. In other parts of the world, they can be used in animal husbandry, leading to these hormones being present at higher levels in the milk as well.

When it comes to sex hormones, these occur in milk, because they are naturally secreted. In dairy animals, there levels fluctuate over lactation, especially due to most cows being pregnant during lactation. In late lactation, sex hormone levels are therefore somewhat higher.

What happens to these hormones during processing? Research shows that the hormones stay largely intact, except for BST that is broken down during regular dairy processing. There is no difference in hormone levels between regular and organic milk (assuming both did not inject hormones in their dairy animals). For comparison, breast milk contains 10-20 times higher levels of sex hormones than bovine milk.

After processing, we consume the milk. So does this cause any harm? If we look at growth hormones, BST is naturally broken down in our digestive tract. IGF-1 is not broken down, but levels in milk are lower than normally occurring levels of IGF-1 in our body. Sex hormones are also not broken down during digestion. But if we look at sex hormone intake through milk (and animal products in general), they are lower than our daily maximum intake, even at high consumption levels (liters per day). So, in conclusion, although milk (and animal products in general) contribute to dietary hormone intake, it is at such low levels that health effects are not to be expected.

Kasper Hettinga, December 2016

Is milk full of antibiotics?

Last week, there was European Antibiotics Awareness day. So, I took this opportunity to discuss the story that sometimes goes around on social media that milk is full of antibiotics nowadays.

So can there be antibiotics in milk? Yes, there can. If cows have an infection, they are treated with antibiotics, just like us humans. An important reasons that dairy cows get treated with antibiotics is an infection in the udder. The antibiotics used for this treatment can end up in the milk. The milk of cows treated with antibiotics should thus be collected separately and not go into the milk tank, to prevent contamination of the milk in the tank.

Because dairy processor want to be sure about the absence of antibiotics, every individual milk delivery is checked for the presence of antibiotics, before the milk is unloaded at the factory. If milk is found to be contaminated with antibiotics, the milk is destructed and the farmer get a financial penalty.

Besides human health, there is a second reason why dairy factories strictly control the absence of antibiotics, which is the effect it has on fermentation. Many dairy products (e.g. yoghurt and cheese) are made by fermentation, which is a process in which bacteria grow in the milk to achieve the specific taste & texture required. These bacteria used for fermentation do not grow if antibiotics are present. So that is an important reason to check every individual batch of milk delivered to the factory on the presence of antibiotics.

In conclusion, because every individual batch of milk is checked to confirm absence of antibiotics, milk is not a source of antibiotics in the human diet.

Kasper Hettinga, November 2016

Raw milk: friend or foe

In recent years, the interest in consuming raw, unprocessed food products is increasing. An example of this is the consumption of raw milk. In this blog, I will discuss both the safety risks and potential health benefits of raw milk.

Safety of raw milk

The reason milk needs to be at least pasteurised before sale according to European law is safety. All pathogens in milk that are a potential health risk (e.g. Listeria, Salmonella) are killed with such heat treatment. Especially for young children, pregnant women, and elderly, these pathogens can cause severe health problems. Even though the contamination of milk with these pathogens can be minimized, and rapid testing exists, safety can never be fully guaranteed for raw milk.

Nutrients in raw milk

Proponents of consuming raw, unprocessed foods often focus on the retention of nutrients. Indeed, quite a number of nutrients are heat sensitive. The extent of the resulting heat damage depends on the specific nutrient. If we look specifically at milk, protein and B vitamins are the main nutrients of concern. For milk, pasteurisation and UHT sterilisation are the most common heating techniques. Pasteurisation is a rather mild treatment (72°C for 20 seconds) that does not damage nutrients in milk. UHT sterilisation is somewhat more intense, with higher temperatures for very short times (130-150°C for 5-10 seconds). Although small losses of B-vitamins happen, the effect is still rather small. So in the end, heating of milk does not (pasteurisation) or hardly (UHT sterilisation) affect its nutritiousness compared to raw milk.

Health benefits of raw milk

Several studies have been done showing health benefits of raw milk drinking. Especially when it comes to infections, allergy, and asthma in children, there are several studies showing such benefits. Specific immunologically-active milk proteins are very heat sensitive and may underlie this effect. However, the real causal factor(s) underlying the potential health benefits of raw milk consumption are unknown. Also, for ethical reasons, no human intervention trials have been done with raw milk, limiting existing evidence to epidemiological studies, making a cause-effect relation even more difficult to establish.


So, should we drink raw milk to prevent infections, allergies, and asthma? Due to risks associated with raw milk drinking, I do not believe this to be the solution. What I believe should happen is research on better understanding of the causal factor(s) underlying the effects. Then we can use that knowledge to optimize our dairy processing, trying to keep these components intact, while still producing safe dairy products, either using regular heating or non-thermal techniques like UV-C. And for those drinking UHT sterilized milk, switching to fresh pasteurised milk may be beneficial, as more immunologically-active proteins are retained.

Kasper Hettinga, November 2016

Is A2 milk going to make us healthy?

Around the world, A2 milk is being sold. Due to its market launch in The Netherlands, I decided to take a closer look at the product, and the science behind it. But before going into the details, first I want to explain what A2 milk is. Milk contains 6 major proteins, 4 caseins (that are the basis of cheese making) and 2 whey proteins (that remain in the whey after cheese making). One of these four caseins is β-casein, which is also the second most abundant protein in milk. This β-casein has an amino acid composition that depends on a gene, that can have small variations. The two main version are A1 and A2, which differ by one amino acid. During breakdown of β-casein, this can lead to the formation of a peptide called BCM-7.

Primaeval cow

In the Netherlands, the milk is marketed as coming from primaeval cows. Also in other countries, marketing focuses on the fact that A2 is the original β-casein, and A1 is the version that comes in our current milk due to breeding. This is simply not true. In all kind of cow breeds other than the regular Holstein cows, A1 and A2 can both be found. Between breeds, there is a difference in the ratio of the A1 and A2 gene. But A1 can be found in all cow breeds, not only modern breeds. On top of that, for the Dutch Friesean Holstein breed (most popular dairy breed in the Netherlands) actually at least 70% has the A2 gene for β-casein. And due to the positive association between A2 and protein yield, breeding programs will probably increase A2 further in future. Not because they believe it is healthy, but simply for economic reasons.

BCM-7 and chronic disease

In the 1990’s and early 2000’s, a lot of attention was on the potential link between BCM-7 and chronic disease. Originally, this was based on epidemiological studies, but on further investigations, these were not reliable to assess the relation between β-casein and chronic disease risk. In animal models where BCM-7 is directly injected in the blood stream, negative effects were shown. But trials in humans eating caseins have never been able to show this happens in people. The most probable reasons for this is that BCM-7 can be, and therefore probably is, further broken down in our intestinal tract. This has been confirmed in a 2009 EFSA report, which came to the conclusion that A1/A2 is not plausibly related to chronic diseases.

A1/A2 casein and cow’s milk allergy

A lot of farms selling A2 milk directly to consumers focus on cow’s milk allergy. I’ll be short on this one. Because 1) hardly any person with cow’s milk allergy is allergic to β-casein alone, and 2) only one amino acid is changed, I don’t expect any cow’s milk allergic person to benefit from A2 milk. And for the people who claim it helps, I have never seen evidence in double blind provocations, but always based on self-diagnosis, which is known to be very unreliable in food allergy in general.

A1/A2 casein and intestinal discomfort

Recently, a new hypothesis has popped up, the β-casein variant may be related to intestinal discomfort. This is a difficult to categorize “illness” (if you can call it an illness), so very popular for healthy products that can’t make strong claims. Intestinal discomfort may be from lactose intolerance, but in that case A2 milk won’t help. Then there are the people with undiagnosed weak symptoms (among whom gluten-free products are also popular). A recent study on 45 Chinese people, they showed a small decrease in intestinal discomfort after consuming A2 milk for 2 weeks. I’ll be a bit careful on this one. Many small-scale (low number of participants, short intervention) nutrition studies can’t be replicated, so we’ll need to see how that goes with this study. Also, we don’t know whether, even if replicated, Europeans (where lactose intolerance is less common) would respond the same. So we’ll just have to wait for further proof. In conclusion, for the time being, I don’t see any reason, for anyone, to already consume A2 milk.

This blog is based on two blogs I earlier wrote in Dutch for the The Milk Story

Kasper Hettinga, October 2016