Composition

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What is raw milk?

Raw milk is milk that has not been heat treated (pasteurised). Currently it is not legal to sell raw milk in South Africa except in cases where the herds have been certified free from tuberculosis and brucellosis.

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Raw milk is untreated milk, exactly as it comes from the cow. With reference to national health legislation, raw milk has not undergone pasteurisation, sterilisation or ultra-high temperature treatment. Raw milk could carry bacteria that may pose serious health risks to the consumer. It is illegal to sell raw milk in South Africa unless it has been approved by health authorities.

What is organically farmed milk?

Organic farming avoids the use of commercial fertilisers, pesticides, feed additives and other chemicals. Organic milk does not differ much from standard milk, but may be lacking in iodine. Most of the nutritional differences are small and relate to the specific pasture grazing of organically reared cows.

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Organic farming avoids the use of soluble fertilisers, pesticides, feed additives and other chemicals. Most of the nutritional differences are small and relate to the specific pasture grazing of organically reared cows.

Milk labelled as organic usually contains higher amounts of omega-3 fatty acids, although the absolute amount is still quite low. Opting for organically produced milk may have little effect in the context of an individual’s overall diet. Organic milk also contains about a third less iodine than milk produced through conventional farming systems. Iodine contributes to cognitive function and is therefore particularly important for pregnant women. The availability of organically produced milk is still limited in South Africa.

What is fortified milk?

Fortified milk is milk to which specific nutrients (vitamin D, folic acid, iron, protein) have been added. In South Africa, fresh milk is normally not fortified. Some UHT products in the retail market may be fortified.

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Fortified milk is milk that has been enriched with specific nutrients. The choice of added nutrients is based mostly on common dietary deficiencies seen in specific consumer categories, such as the elderly, women during pregnancy or growing children.

In South Africa, fresh milk is currently (Jan 2018) not fortified, although typical fortifications elsewhere in the world include folic acid, vitamin D, iron or protein.

What type of heat treatments can milk undergo?

Four different methods are used to heat treat milk to make it safe and extending the shelf life: pasteurisation; ultra-pasteurisation; ultra-high temperature treatment; sterilisation.

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Appropriate heat treatment limits harmful bacteria that may be present in food and ensures that the food is safe for consumption. Milk can be heat treated through four different methods:

  • Pasteurisation involves heating milk to a high temperature (72 °C), followed by rapid cooling to 4 °C.
  • Ultra-pasteurisation involves treatment at a higher temperature and products treated in this way may stay fresh for more than 14 days if kept at 4 °C or lower.
  • Ultra-high temperature treatment involves heating milk to between 135 °C and 150 °C for two to four seconds and then cooling it to 4 °C or lower. This treatment is used to produce long-life milk.

Sterilisation involves heating filled bottles of milk to between 110 °C and 130 °C for approximately 10–30 minutes, after which the bottles are cooled with cold water. Unopened bottles of sterilised milk keep for a long time without having to be refrigerated. Once opened, it must be treated as fresh milk.

Is all milk pasteurised?

No, not all milk is pasteurised. But it’s not legal to sell raw milk in South Africa unless a herd is certified as free from tuberculosis and brucellosis.

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No, not all milk is pasteurised. However, it is illegal to sell raw milk for direct use in South Africa unless the specific municipality where the sale is taking place is authorised to do so in terms of the law (R1555). A farm selling raw milk must be able to present a certificate stating the herd as being free of tuberculosis and brucellosis. Even then, raw milk should be dealt with cautiously and best be properly heated prior to use.

What is pasteurised milk?

Pasteurisation is a heat treatment used to destroy harmful bacteria in food. It ensures that milk is safe to drink and extends its shelf life.

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Pasteurised milk is milk that has been heated to a temperature of 72 °C and then cooled rapidly to 4 °C. Pasteurisation is one of several heat treatments used to limit harmful bacteria that may be present in food. Pasteurisation ensures that milk is safe for human consumption and extends its shelf life. Pasteurised milk always requires refrigeration.

What is powdered milk?

Powdered or dried milk is manufactured by spray drying (removing water from liquid milk). Most of milk’s natural colour, flavour, solubility and nutritive value are preserved.

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Powdered or dried milk is commonly manufactured by spray drying. This method involves removing water from liquid milk in stages. During the first stage, the milk is evaporated by using vacuum and mild heat. This concentrates the solids to approximately 50%. The concentrate is then sprayed as a fine mist into a heated chamber, which lets the last water evaporate from the minute droplets. This process happens at about the same temperature as pasteurisation and so prevents any significant nutrient loss. Spray drying retains most of milk’s natural characteristics and properties, such as colour, flavour, solubility and nutritive value. Milk can also be freeze dried, but this process is much more expensive and therefore not as commonly used.

Drying milk is an effective way not only to reduce the bulk of the product and so save on transport costs, but also to extend the shelf life of the product.

Powdered milk is useful as ingredient in many products and can be reconstituted to liquid milk with water. In its dry state it does not require refrigeration.

What is flavoured milk?

Flavoured milk is pasteurised and homogenised low-fat or fat-free dairy milk that is coloured, sweetened and flavoured. It provides the same nine essential nutrients as white or unflavoured milk. In contrast to sugar-sweetened soft drinks, flavoured milk does not add ‘empty kilojoules’ to the diet and is therefore a better choice than a high-sugar, low-nutrient drink.

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Flavoured milk is a pasteurised and homogenised low-fat or fat-free dairy milk product that is coloured, sweetened and flavoured. It provides the same nine essential nutrients as white or unflavoured milk. Most flavoured milks undergo either an ultra-heat treatment or a sterilisation process, which removes all micro-organisms. Flavoured milk has a long shelf life and generally does not have to be refrigerated before it is opened.

Flavoured milk is a nutrient-dense beverage, which means that it contains many important nutrients relative to its energy content. Although flavoured milk contains both natural milk sugar (lactose) and additional table sugar (sucrose), these sugars contribute only about 3% energy per 100 ml. Sugar-sweetened soft drinks provide more than 20% energy per 100 ml. So, although flavoured milk is sweetened, it also provides important nutrients such as protein, calcium, potassium, magnesium, phosphate and zinc, and vitamins A, B12 and B2. Flavoured milk does not add empty kilojoules to the diet and is therefore a wiser option than a high-sugar, low-nutrient beverage.

How do dairy alternatives compare with cow’s milk?

Many different drinks made from seeds, fruits (coconut), nuts (almond), legumes (soybeans), or cereals (rice, oats) are commonly used to replace cow’s milk. Plant-based beverages differ from cow’s milk in nutrient content and they are low particularly in protein, natural calcium, vitamin B2, vitamin B12, iodine, potassium and phosphorus. Plant-based beverages also contains added sugar for taste.

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Beverages made from seeds or fruits, nuts, legumes or cereals are commonly used as alternatives to cow’s milk. Popular choices include coconut milk, almond milk, soy milk and rice or oat milk. The nutritional composition of these plant-based ‘milk’ products depends on the source, methods of processing and fortification, and differs from that of cow’s milk. Cow’s milk is a natural source of well-absorbable and highly bioavailable protein, calcium, vitamin B2 (riboflavin), vitamin B12, iodine, potassium and phosphorus. Plant-based beverages are not naturally high in nutrients and therefore have to be fortified, specifically with calcium and vitamin B12.

Dairy milk (cow’s milk or goat’s milk) typically contains approximately 3.3% protein, whereas plant-based milk alternatives generally contain around 0.5% protein (this excludes soy milk, which has a protein content similar to that of dairy milk). Cow’s milk is also naturally high in ‘complete’ protein, whereas plant-based beverages contain mostly ‘incomplete’ protein. The protein in cow’s milk also has a higher bioavailability than that of plant-based beverages.

Of the plant-based milk alternatives:

  • soy milk provides the best source of plant protein, but it does not naturally contain calcium and vitamin B12, and is therefore often fortified with these nutrients
  • rice milk is much lower in protein, very high in carbohydrates and has to be fortified with calcium and vitamins D and B12
  • almond milk contains very little protein (just 1 g per glass), but it does contain calcium and vitamins D and E; only limited research is available on the bioavailability and absorbability of the calcium in almond milk
  • coconut milk has little protein and a very high total fat content (11.2 g/100 ml), of which 1.6 g/100 ml is saturated fat, and does not naturally contain calcium.

Some plant-based beverages contain added sugar for taste, while milk naturally contains a sugar called lactose.

Does milk naturally contain vitamin D?

Milk naturally contains only a tiny amount of vitamin D. In contrast to some other countries, no vitamin D is added to milk in South Africa.

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Milk naturally contains only a negligible amount of vitamin D, which is a fat-soluble vitamin that enhances the intestinal absorption of calcium and phosphorus. Vitamin D is therefore essential for the maintenance of a healthy skeleton throughout life. Although milk is fortified with vitamin D in many countries, it is not the case in South Africa. Because of the high level of sunshine in South Africa, it is assumed that most people living in South Africa should be able to obtain adequate vitamin D from 10–30 minutes of sunlight per day.