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Which cow’s milk is best for you

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Choosing the best cow’s milk for your family is not an easy process. Tracy Simaika, registered dietitian & certified Diabetes Educator gives her professional opinion.

Living and raising a family in Hong Kong is a wonderful and unique adventure for many expats – but it is not without its challenges. Just popping down to the grocery store to pick up a carton of milk can leave a person scratching their head when it comes to choosing the safest and healthiest kind to buy. The quandary becomes even more of an issue when the time comes to introduce cow’s milk to a baby. I’ve noticed a lot of moms asking each other about this.

As a new mom living in Hong Kong, I decided to research this question for myself, looking at the different issues that come up when choosing milk.

Milk vs. Milk Drink

When you go to the refrigerated section of the supermarket, you naturally assume you are picking up “fresh”, just milked from the cow, milk. “Fresh” is a bit of a relative term and while milk is, in fact, milk be aware of the possible addition of the word “drink”. In the refrigerator section, mixed in with each other, you will find some cartons that are labeled “milk” and other cartons labeled “milk drink”. While not necessarily a health or nutrition concern, you might be interested to know that “milk drink” means that the product has been reconstituted by combining dry milk powder, or concentrated milk, with water – usually in the same proportion as in the original form of the milk.

These proportions sometimes vary, however. Reconstituting milk is not a new practice here in Hong Kong. For many years, people living in remote areas, or in areas without refrigeration, often purchased dried milk powder which they could reconstitute as needed. Also, just for general interest, fresh milk that is for sale in Hong Kong is not from local dairy cows as no dairy cows are currently being raised here. The cows used for milking are located nearby in mainland China and there are some companies in Hong Kong who then process and package that milk for local distribution. Other fresh milk for sale in Hong Kong has been flown in from countries such as the USA, Australia and New Zealand. This milk has been pasteurized and processed in its originating country, allowing the milk to stay fresh under the right conditions for up to 21 days. Given the distance the milk must travel to reach your grocery store, part of that shelf life has been used up by the travel time but that is not an issue as long as the milk has been properly handled during transport and has not passed its expiry date.

Fresh vs. UHT

Pasteurization is the process by which milk is heated to a minimum required temperature for a set amount of time in order to remove 99.9% of the bacteria that can cause very serious forms of food poisoning.

There are two common pasteurization methods. The first one is often simply referred to as “pasteurization”, meaning that the milk was heated to 74C for 10-20 seconds. The second method is Ultra High Temperature (UHT) pasteurization, in which the milk is heated to a hotter temperature (138C), for a much shorter amount of time (3 seconds). The latter type of processing means the milk does not have to be refrigerated before opening and extends its shelf life (up to 6 months). The UHT process is also used for coffee creams, soy milks, juices, soups and other products that are sold in tetra packs and, likewise, they do not require refrigeration.

Either form of pasteurization allows for the majority of the milk’s nutritional quality to remain intact while virtually completely removing the risk for food poisoning. Pasteurization can, however, lead to a loss of up to 20% of the vitamin content of the milk which may or may not be refortified in the final product depending on the manufacturer. There are also some physical and chemical changes to the milk fat and protein. The most noticeable impact of these changes is on the taste of UHT milk (due to caramelization of the milk sugar). The amount of vitamins, especially the fat-soluble vitamins A & D, are also affected by the fat content of the milk with higher fat milks having higher levels of these vitamins.

Hormones

When people discuss hormones in milk, they are usually referring to the hormone “Recombinant Bovine Somatotropin” (rBST). This particular synthetic hormone was designed to increase the milk production of dairy cattle. While it has not been found to be a risk to human health, it has been clearly linked to mastitis, infertility and other health problems in the cows it is given to.

Due to these animal health concerns, several countries have banned the sale of rBST based on the potential harm to cows. While Canada, Australia, New Zealand, Japan and 27 countries in the EU have not approved this hormone others, like the USA, have approved it and continue to allow its use. In terms of human safety, The European Commission for Food Safety wrote a report on the “Public Health Aspects of the Use of Bovine Somatotropin” and brought up two health issues that require further research.

1) The use of rBST is known to increase the levels of an insulin-like growth factor (IGF-1) in cow’s milk. There is research that has noted links between IGF-1 and an increased risk of cancer, especially of the breast and prostate.

2) Studies of animals given rBST have raised concerns over potential changes to milk protein that could lead to allergies in people consuming the milk.

Antibiotics

There is a lot of concern that the misuse of antibiotics in the rearing of cattle and other animals used for food production is leading to the growth of antibiotic resistant bacteria. As one of the common side-effects of using rBST in cows to increase milk production is mastitis, it is not surprising, then, that this is also the most common problem requiring the use of antibiotics in dairy cows. In Canada, and several other countries, any cow that requires antibiotics for any reason must go through a withdrawal period. Until that period is completed, the milk from the cow must be collected separately and discarded. It cannot be processed and sold for human consumption.

Antibiotics may be the most talked about contaminant in milk, but it is worth noting that heavy metals, pesticides, insecticides and other undesirable contaminants that can be found in animal feed may also later be found as residues in milk. The full extent and impact of this is still being studied. In the meantime, it may be worth thinking about where and how the cows that are providing you with their milk (and whose milk is being used in other products) are being raised.

Organic Milk

On an organic farm, all cows must have daily access to pesticide/herbicide-free pasture, paddocks or runways. The cows must be fed a nutritionally balanced organic feed. However, antibiotics can still be used to treat infection as the welfare of the animal comes first!

The milk must then also be withheld for a minimum period during and after the time the animal is on the antibiotics before the milk can be used again, just as on a non-organic farm.

Advice

What should you look for at the store?
• If your child is under 2 years of age they need the fat – so it is not advisable to give low fat or fat-free milk products to these young children

• UHT milk is not nutritionally inferior to “fresh” pasteurized milk, particularly if it has been fortified with vitamins, so, if it makes sense economically or for the convenience of keeping an extra litre in the cupboard, go for it

• If you are worried about the use of hormones and/or misuse of antibiotics in the production of milk, you may want to choose milk from countries that regulate against this, such as Australia or New Zealand

• In terms of environmental pollutants, this is harder to monitor (i.e. was a pesticide sprayed on a field a cow ate from?). However, it doesn’t hurt to use your purchasing power to support farms and practices that limit exposure to these chemicals in the feed and living environment of the cow (such as in organic foods). Money speaks!

References:
Forge, Frederic (1999). Recombinant Bovine Somatotropine.
Parliamentary Research Branch: Science and Technology Division.
Received from: http://publications.gc.ca/collections/Collection-R/
LoPBdP/BP/prb981-e.htm#Animal%20Health%28txt%29
Scientific Committee on Veterinary Measures Relating to Public Health.
Report on Public Health Aspects on the Use of Bovine Somatotrophin
15-16 March 1999. http://ec.europa.eu/food/fs/sc/scv/out19_en.html
Health Canada. Drugs and Health Products – Hormonal Growth
Promoters http://www.hc-sc.gc.ca/dhp-mps/vet/faq/
growth_hormones_promoters_croissance_hormonaux_stimulateurseng.
php
Khaniki, G. International Journal of Diary Science 2(2): 104-115. 2007
Chemical Contaminants in Milk & Public Health Concerns: A Review.
http://scialert.net/qredirect.php?doi=ijds.2007.104.115&linkid=pdf
Bulloch, B. Milk Does the Body Good…or Does It? Dairy Industry
Confusion. http://www.foodtofit.ca/index.php?page=BlogDetail&id=77

Contact Tracy at tracy.simaika@gmail.com

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