All About Milk

Milk

Properly prepared milk is always foamed. Integrating air into the milk improves the taste. Milk that has not been foamed at all tends to taste flat and dull by comparison.

Great milk properly prepared has foam combined throughout the entire pitcher of milk. The foam will not be sitting on the top with the steamed milk underneath. The quantity of foam you have incorporated into the milk will be dependent on how much is required for the drink and how aggressively you worked to incorporate air into the milk.

So for a latte where less foam is required, the volume of milk will have expanded by approximately one-third due to foam and for a cappuccino it will have approximately doubled.

Now let’s talk about MILK.

Organic milk is produced by dairy farmers that use only organic fertilizers and organic pesticides, and their cows are not given supplemental hormones (rBST). Dairy farmers and producers make many specialty forms of milk to meet consumer preferences and needs. Organic milk is also available as lactose-free and ultra-pasteurized.

The organic label is not a judgment about the quality or safety of the milk. As with all organic foods, it’s the process that makes milk organic, not the final product. The nutrient content of organic milk is the same as standard milk and offers no additional health benefits compared to standard milk. Stringent government standards that include testing all types of milk for antibiotic and pesticide residues ensure that both organic milk and conventional milk are pure, safe and nutritious.

Raw milk is what you get when you milk a cow.  Nothing is added, removed or heated.  All of these totally awesome and amazing nutrients and enzymes found in raw milk are still fully in tact:

  • calcium
  • phosphate
  • magnesium
  • sodium
  • potassium
  • citrate
  • chlorine
  • vitamin A
  • vitamin B6
  • vitamin B12
  • vitamin C
  • vitamin D
  • vitamin K
  • vitamin E
  • thiamine
  • niacin
  • biotin
  • riboflavin
  • folates
  • pantothenic acid

Raw milk represents only a very small fraction of total milk consumption. Animal Health Dairy Hygiene has estimated this to be 0.01% of total cows’ milk consumption.

Dairy cattle kept in confinement lots, fed waste from other food-making processes, and never allowed to roam free on pasture, are unhealthy and therefore produce unhealthy milk.

The fact is, way back in the 1800’s hygiene standards weren’t up to scratch or enforced like they are today, so people were getting sick from drinking raw milk.

But times have changed and we have new technology and refrigeration devices like stainless steel tanks, milking machines, refrigerated trucks and inspection methods which now make pasteurisation unnecessary.

The co-founder and president of Weston A. Price Organization and author of Nourishing Traditions, states the safety of raw milk depends on where it comes from.

“Raw milk from a confinement dairy would be quite risky. Raw milk from pasture fed cows where the milk is produced in clean conditions is an inherently safe food. There are components in the raw milk that kill pathogens and that also support the immune system. When animals are pasture fed, the E. coli goes way down and in some cases disappears. When pasture fed raw, cleanly produced milk is tested for pathogens – they aren’t there.”

But isn’t raw milk illegal? 

Selling raw milk products in Australia is currently illegal. However, it’s not illegal to buy, possess or consume raw milk. It is for this reason that you will see raw milk in health food stores labelled “bath milk”. Some suppliers have been charged and fined for selling raw milk for drinking but as long as everyone agrees that all the consumer is doing is bathing in it everything is fine.

To put all this in perspective – it’s legal to sell cigarettes, even though they’ve been proved to cause disease, it’s legal to sell alcohol with all the documented health and psychological effects, but it is illegal to sell raw milk to consenting adults. Go figure!

Whole milk is milk that has not had its fat content reduced. One cup of whole milk contains 8 grams of total fat, of which 5 grams are saturated. This type of milk has the highest fat content of any cow’s milk. According to the U.S. Department of Agriculture’s nutritional database, a 1-cup serving of whole milk contains 158 calories, 8 grams of protein, 13 grams of carbohydrates and 12 grams of sugar. One serving contains 12 percent of the daily recommended value of cholesterol and 30 percent of the daily recommended value of calcium.

Most milk undergoes processing before you buy it at the store. The three primary steps include: pasteurization, homogenization and fortification.

Pasteurized milk is everything else. If it’s not raw, it’s pasteurized.

Most of the milk consumed in Australia, New Zealand, Europe, Scandinavia and the USA is pasteurized.

That huge list of awesome nutrients and enzymes above are non-existent in the pasteurized milk. The rapid heating and cooling of milk destroys disease-causing microorganisms but increases the shelf life of the milk. The high heat used in the process killing healthy bacteria and enzymes also damages the remaining nutrients so that our bodies do not benefit from them.  Dairy manufacturers know this, as do food scientists, so milk sold in stores is fortified with synthetic nutrients that our bodies treat as foreign chemicals. The loss of calcium and phosphorus is about 5%. Thiamine and Vitamin B12 go down by 10% and 20% of Vitamin C is lost.

These valuable nutrients are unable to be assimilated by the body after pasteurization, because the beneficial enzymes our bodies need to break the nutrients down are destroyed.

MILK CAN BE PASTEURIZED TO THREE DIFFERENT LEVELS:  ULTRA-HIGH TEMP (UHT), HIGH-TEMPERATURE SHORT-TIME (HTST) AND LOW-TEMP.

Ultra-high temperature (UHT) milk is pasteurized at a much higher temperature, higher than 135°c for more than two seconds to make it sterile. This is the milk you find in aseptic (cardboard) containers.  Non-refrigerated, shelf-stable milk is definitely UHT. Refrigerated milk may or may not be UHT. The refrigerated coolers have both cardboard and aseptic containers, so make sure you read the labels first.

The basic process for whole milk involves heating the milk to a temperature of no less than 71.7ºC for a minimum of 15 seconds (max 25 seconds). This process is known as High Temperature Short Time (HTST).

After this the cold milk that enters the heat exchanger is heated by the hot milk leaving it, which in turn is partly cooled. Following heating, the milk is cooled rapidly to below 6ºC using chilled water on the opposite side of the plate. This process also extends the keeping quality of the milk.

Low-Temp milk is heated to 62.7°c for at least 30 minutes

After pasteurization, milk undergoes homogenization to reduce the fatty sensation of whole milk and prevent the formation of a cream plug. Homogenization of milk involves forcing the milk at high pressure through small holes. This breaks up the fat globules in order to spread them evenly throughout the milk and prevent separation of a cream layer. This process basically results in milk of uniform composition or consistency and palatability without removing or adding any constituents. Homogenization increases the whiteness of milk because the greater numbers of fat globules scatter the light more effectively.

Finally, milk is fortified to increase its nutritional value or to replace nutrients lost during processing. Vitamin A is frequently added to reduced-fat, low-fat and fat-free milks

 Milk designated as two percent or low fat has a 2 percent fat-to-weight ratio. One cup of this type of milk contains 5 grams of fat, of which 3 grams are saturated. A 1-cup serving of 2 percent milk contains 139 calories, 10 grams of protein, 15 grams of carbohydrates and 13 grams of sugar. One serving also contains 7 percent of your daily recommended value of cholesterol and provides you with 35 percent of your daily value of calcium.

Semi skimmed milk is the most popular type of milk with a fat content of 1.7%, compared to a minimum of 3.5% in whole standardized milk and 0.1% in skimmed milk.

As with 2 percent milk, the percentage in this type of milk indicates the percent of fat to weight. One percent milk has roughly half of the fat of 2 percent milk. There are 2 grams of total fat in 1 cup of 1 percent milk, of which 2 grams are saturated. A serving of 1 percent milk contains 127 calories, 10 grams of protein, 16 grams of carbohydrates and 15 grams of sugar. One cup of 1 percent milk also contains 4 percent of your daily recommended value of cholesterol and 38 percent of your daily value of calcium. 1% fat milk

The nutritional differences between semi-skimmed and 1% fat milk are small and dependent mainly on the difference in fat content.  1% fat milk contains 40% less total and saturated fat than standard semi-skimmed milk. In addition, it has a lower energy content than semi-skimmed, and slightly lower levels of vitamins A and E, but has a higher calcium content.

Skimmed milk has a fat content of between 0-0.5% and an average fat content of 0.1%. Skimmed milk therefore has nearly all the fat removed.

It contains slightly more calcium than whole milk and lower levels of fat soluble vitamins, particularly vitamin A, as this is lost when the fat is removed.

The lower level of fat in skimmed milk reduces its calorie (energy) content.  For this reason it is not recommended for children under the age of 5 years as they need the extra energy for growth. However it is ideal for adults who wish to limit their fat or calorie intake.

Skimmed milk has a slightly more watery appearance than other types of milk and has a less creamy taste due to the removal of fat.

Non-fat milk has been entirely stripped of its fat molecules. This type of milk is not calorie free, however. And because non-fat milk contains carbohydrates and sugars, it can still affect your weight. This is a good option if you are limiting your fat intake or monitoring your cholesterol. One cup of non-fat milk has 92 calories, 9 grams of protein, 13 grams of carbohydrates and 12 grams of sugar. One serving has 2 percent of your daily value of cholesterol and 31 percent of your daily recommended value of calcium.

Organic milk comes from cows that have been grazed on pasture that has no chemical fertilisers, pesticides or agrochemicals used on it.

The producers must register with an approved organic body and are subject to regular inspection.

Once the cows have been milked, the milk is treated in exactly the same way as regular pasteurised milk.

There is no evidence to suggest that organic milk is any more nutritious than conventionally produced milk. Although there have been studies to show that organically produced milk contains higher levels of omega-3 polyunsaturated fatty acids, these are plant derived, short-chain fatty acids which appear to be of limited health benefit compared to the longer chain omega-3 fatty acids found in oily fish.

Channel Island milk is produced from Jersey or Guernsey breeds of cow and has a particularly rich and creamy taste.

It tends to be slightly higher in calories and fat than regular whole milk and also has a higher content of fat soluble vitamins -particularly vitamin A which is important for the promotion and maintenance of healthy growth and development.

Jersey and Guernsey milks tend to have a visible cream line and are commonly found in supermarkets as “breakfast milk”.

The flavoured milk market is one of the fastest growing dairy sectors.

There are a wide variety of flavours and consistencies to cater for all ages and tastes with a choice of long-life (i.e. Ultra Heat Treated or sterilised) or fresh flavoured milk.

Most flavoured milk products are produced using reduced fat milk varieties and usually have a fat content of around 1%.

The most popular flavours are chocolate, strawberry and banana however more sophisticated flavours such as peach, mocha or products made with real Belgian and Swiss chocolate have been developed for the more adult market.

In comparison with plain milks, flavoured milks tend to have slightly higher sugar content, however studies have suggested that they are still a favourable option for children and teenagers as they provide a wide range of beneficial nutrients.

One study has shown that children consuming flavoured milk are not actually likely to have higher sugar or energy intakes as children consuming flavoured milk would likely, consume fewer less healthy sweetened drinks.

Flavoured milk is also less likely to cause damage to teeth than sugary foods and drinks.

Interestingly recent studies have suggested that chocolate flavoured milk can be used as an effective recovery aid after intense bouts of exercise.

Sterilised milk is available in whole, semi skimmed and skimmed varieties. It goes through a more severe form of heat treatment, which destroys nearly all the bacteria in it.

Firstly the milk is pre-heated to around 50oC, then homogenised (see below for a brief outline of homogenisation), after which it is poured into glass bottles which are closed with an airtight seal.

There is no legally defined process for sterilising milk but, commonly, filled bottles are carried on a conveyor belt through a steam chamber where they are heated to a temperature of between 110-130ºC for approximately 10-30 minutes. Then they are cooled using a cold water tank, sprays or, in some cases, atmospheric air and then crated.

The sterilisation process results in a change of taste and colour and also slightly reduces the nutritional value of the milk, particularly the B group vitamins and vitamin C.

Unopened bottles or cartons of sterilised milk keep for approximately 6 months without the need for refrigeration. Once opened it must be treated as fresh milk and used within 5 days.

Much of the milk in the market is now homogenized as well as pasteurized. Homogenization offers a way to reduce the fatty sensation of whole milk and prevent the formation of a cream plug.

Evaporated milk is a concentrated, sterilized milk product. It has a concentration twice that of standard milk.

The process of producing evaporated milk involves standardising, heat treating and evaporating the milk under reduced pressure, at temperatures between 60ºC and 65ºC.

The evaporated milk is then homogenised to prevent it separating under storage and then it is cooled.

The evaporated milk is poured into cans, which are then sealed. At this point the cans are moved to a steriliser where they are held for 10 minutes.

A cooling stage follows and the cans are then labelled and packed.

As a result of processing, evaporated milk possesses a characteristic cooked flavour as well as a characteristic colour.

The shelf-life of canned evaporated milk is commonly stated as one year stored at ambient temperatures, though in practice the product will keep for longer.

Condensed milk is concentrated in the same way as evaporated milk, but with the addition of sugar.

This product is not sterlised but is preserved by the high concentration of sugar. It can be made from whole milk, semi skimmed or skimmed milk.

The heat treatment used consists of holding standardised milk at a temperature of 110-115ºC for one to two minutes.

The milk is then homogenised, the sugar added and the sweetened milk is then evaporated at low temperatures (between 55-60ºC). The concentration of the condensed milk is now up to 3 times that of the original milk.

The milk is then cooled rapidly to 30ºC and packaged.

Sweetened condensed milk is commonly used in the sugar confectionary industry for the production of toffee, caramel and fudge. It is also an alternative to liquid milk which was once traditionally used in these products.

Filtered milk goes through an extra, fine filtration system, which prevents souring bacteria from passing through.

The nutritional content of the milk is unaffected but the shelf life is increased.

The processes involved include, microfiltration, ultrafiltration and nanofiltration.

Microfiltration is the most commonly used process and is a pressure-activated separation process which uses a membrane that is permeable to substances with a low molecular weight but rejects material with a high molecular weight.

In the process of microfiltration of skimmed milk, bacteria are removed using ceramic filters with 1.4 micrometer holes to separate the milk from the bacteria. After this process, virtually all the bacteria present in the milk are removed.

The milk is then homogenised to standardise and evenly distribute the fat molecules, where it then undergoes the pasteurisation process before being chilled down quickly to 5ºC or less.

Microfiltration adds an extra level of cleanness which can extend shelf life up to 45 days when stored at temperatures of up to 7ºC and an average 7 days once opened.

Filtered milk is available in whole, semi skimmed or skimmed milk varieties.

Milk powder is produced by evaporating the water from the milk using heat. The milk is homogenised, heat treated and pre-concentrated before drying.

There are a number of ways to produce dried milk powder including spray drying and roller drying.

In the most commonly used spray drying process, the concentrated milk is introduced into a chamber (usually as a fine mist) through which hot air is circulating. The droplets of milk soon lose their water and fall to the floor as fine powder.

Skimmed milk powder can be mixed easily with water; however whole milk isn’t easily reconstituted due to its higher fat content.

Roller drying is an old process of producing milk powder-this involves spreading the concentrated milk onto heated rollers. The water evaporates quickly and leaves a thin film of powder, which is scraped off the rollers. This powder has a cooked flavour and tends to form lumps when mixed with water.

Whole milk powder contains all the nutrients of whole milk in a concentrated form with the exception of vitamin C, thiamin and vitamin B12. Skimmed milk powder contains hardly any fat and therefore no fat soluble vitamins. However, the protein, calcium and riboflavin content remain unaffected.

If stored correctly, skimmed milk powders can be kept for up to one year. Once they are reconstituted, they must be treated as fresh milk.