Distribution

Glass milk bottles used for home delivery service

A brick of French UHT milk

Because milk spoils so easily, it should, ideally, be distributed as quickly as possible. In many countries milk used to be delivered to households daily, but economic pressure has made milk delivery much less popular, and in many areas daily delivery is no longer available. People buy it chilled at grocery or convenience stores or similar retail outlets. Prior to the widespread use of plastics, milk was often distributed to consumers in glass bottles, and before that in bulk that was ladled into the customer's container.

In the UK, milk can be delivered daily by a milkman who travels his local milk round (route) using a battery-powered milk float during the early hours. Milk is delivered in 1 pint glass bottles with aluminium foil tops. Silver top denotes full cream unhomogenised; red top full cream homogenised; red/silver top semi-skimmed; blue/silver check top skimmed; and gold top channel island. However more than just milk is delivered - fruit juice (again in reusable glass bottles), eggs, bread, butter, meat, potatoes, household items and much more.

Empty bottles are rinsed before being left outside for the milkman to collect and take back to the dairy for washing and reuse. Nowadays many milkmen operate franchises as opposed to being employed by the dairy and payment is made at regular intervals either by leaving a cheque out or by cash collection.

Although there was a steep decline in doorstep delivery sales throughout the 1990s, the service is still prominent. Nowadays dairies have diversified and the service is becoming more popular again. The doorstep delivery of milk is seen as part of the UK's heritage, and is relied upon by people up and down the country.

In New Zealand, milk is no longer distributed in glass bottles. In rural India, milk is delivered daily by a local milkman carrying bulk quantities in a metal container, usually on a bicycle; and in other parts of metropolitan India, milk is usually bought or delivered in a plastic sachet.

In the United States bottles were replaced with milk cartons, which are tall boxes with a square cross-section and a peaked top that can folded outward upon opening to form a spout. Now milk is increasingly sold in plastic bottles. First the gallon and half-gallon sizes were sold in plastic jugs while the smaller sizes were sold in milk cartons. Recently milk has been sold in smaller resealable bottles made to fit in automobile cup holders.

The half-pint milk carton is the traditional unit as a component of school lunches. In the US, pictures of missing children were printed on the larger milk cartons as a public service until it was determined that this was disturbing to children.

Milk preserved by the UHT process is sold in cartons often called a "brick" that lack the peak of the traditional milk carton. Milk preserved in this fashion does not need to be refrigerated before opening and has a longer shelf life than milk in ordinary packaging. It is more typically sold unrefrigerated on the shelves in Europe than in America.

Glass milk containers are rare these days. Most people purchase milk in plastic jugs or bags or in waxed-paper cartons, such as those made by Tetra Pak. Ultraviolet light from fluorescent lighting can destroy some of the proteins in milk so many companies that once distributed milk in transparent or highly translucent containers are now using thicker materials that block the harmful rays. Many people feel that such "UV protected" milk tastes better.

Milk comes in a variety of containers with local variants:

• Australia and New Zealand: Distributed in a variety of sizes, most commonly in Tetra Pak cartons for up to 1 litres, and plastic screw-top bottles beyond that with the following volumes; 1.1L, 2L, and 3L. 1 litre Bags are starting to appear in supermarkets, but have not yet proved popular. Most UHT-milk is packed in 1 or 2 litre paper containers with a sealed plastic spout.
• Brazil: Used to be sold in cooled or frozen 1 litre bags, just like for South Africa. Nowadays the most common form is 1 litre Tetra-Pak cartons containing skimmed, semi-skimmed or whole milk.
• Canada: 1.33 litre plastic bags (sold as 4 litres in 3 bags) are widely available in some areas (especially Ontario and Québec), although the 4 litre plastic jug has supplanted them in western Canada. Other common packaging sizes are 2 litre, 1 litre, 500 millilitre, and 250 millilitre cartons, as well as 4 litre, 1 litre, 250 mL Tetra Pak cartons and 500 millilitre plastic jugs.
• China: Sweetened milk is a drink popular with students of all ages and is often sold in small plastic bags complete with straw. Adults not wishing to drink at a banquet often drink milk served from cartons or milk tea.
• Condensed milk is distributed in metal cans, 250 and 125 ml paper containers and 100 and 200 ml squeeze tubes, and powdered milk (skim and whole) is distributed in boxes or bags.
• Parts of Europe: Sizes of 500 millilitres, 1 litre (the most common), 2 litres and 3 litres are commonplace.
• Hong Kong - milk is sold in glass bottles (220 mL), cartons (236 mL and 1L), plastic jugs (2 litres) and Tetra Pak cartons (250 mL).
• South Korea: sold in cartons (180mL, 200mL, 500mL 900mL, 1L, 1.8L, 2.3L), plastic jugs (100Ml and 1.8L), Tetra Pak cartons (180mL and 200mL) and plastic bags (100mL).
• India: Commonly sold in 500 mL plastic bags. It is still customary to serve the milk boiled, despite pasteurization. Flavored milk is sold in most convenience stores in waxed cardboard containers. Convenience stores also sell many varieties of milk (such as flavored and ultra-pasteurized) in different sizes, usually in Tetra-Pak cartons.
• Japan: Commonly sold in 1 litre waxed cardboard boxes. In most city centers there is also home delivery of milk in glass jugs. As seen in China, sweetened milk drinks are very popular to see in vending machines.
• South Africa: Commonly sold in 1 litre bags. The bag is then placed in a plastic jug and the corner cut off before the milk is poured.
• United Kingdom: Most stores stock Imperial sizes: 1 pint (568 mL), 2 pints (1.136 L), 4 pints (2.273 L), 6 pints (3.408 L) or, rarely, a combination including both metric and imperial sizes. Glass milk bottles delivered to the doorstep by the milkman are pint-sized and are returned empty by the householder for repeated recycling. Milk is also sold at supermarkets in either Tetra-Pak cartons or plastic bottles, also measured in pints. Milk continues to be legally sold by the Imperial pint in the UK under EU regulations (a distinction only shared with beer).
• United States: Commonly sold in gallon, half-gallon and quart containers (U.S. customary units) of rigid plastic or, occasionally for sizes less than a gallon, waxed cardboard. The US single-serving size is usually the half-pint (about 240 ml).

Brazilian Yakult, an example of the use of milk.

Varieties and brands

Cow's milk is generally available in several varieties. In some countries these are:

• Full cream (or "whole" in US and UK, "homo milk" in Canada & some US dairies, about 3.25% fat)
• Semi-skimmed ("reduced fat" or "low fat", about 1.5-1.8% fat)
• Skimmed (about 0.1% fat)

Milk in the U.S. and Canada is sold as:

• Whole varieties
• 2% (reduced fat)
• 1% (low fat)
• <0.5% (very low fat)
• Skim (nearly no fat)

In Canada "whole" milk refers to creamline (unhomogenized) milk. "Homogenized" milk refers to milk which is 3.25% butterfat. Generally all store-bought milk in Canada has been homogenized. Yet, the term is also used as a name to describe butterfat content for a specific variety of milk. Modern commercial dairy processing techniques involve first removing all of the butterfat, and then adding back the appropriate amount depending on which product is being produced on that particular line.

In Britain, it is possible to get Channel Island milk, which is 5.5% fat.

In the United States, skim milk is also known as "fat free" milk, due to USDA regulations stating that any food with less than ½ gram of fat per serving can be labeled "fat free".

Full cream, or whole milk, has the full milk fat content (about 3-4% if Freisian- or Holstein-breed are the source). For skimmed or semi-skimmed milk, all of the fat content is removed and then some (in the case of semi-skimmed milk) is returned. The best-selling variety of milk is semi-skimmed; in some countries full-cream (whole) milk is generally seen as less healthy and skimmed milk is often thought to lack taste. Whole milk is recommended to provide sufficient fat for developing toddlers who have graduated from breast milk or infant formula.

In the United States and Canada, a blended mixture of half cream and half milk is often sold in small quantities and is called half-and-half. Half-and-half is used for creaming coffee and similar uses. In Canada, low-fat cream is available, which has half the fat content of half-and-half.

Organic Milk (in the United States) or Bio-Milk & Biologique Milk (in Europe) is milk produced without the use of chemical herbicides or pesticides, and generally with more natural fertilizers and higher standards for the animals, and is now easy to find on the shelves in many areas. Demeter Certified Milk is milk produced according to biodynamic farming methods and is similar in standards to organic milk and biological milk, with a few special farm procedures added that are specific to biodynamic agriculture.

Spoilage

When raw milk is left standing for a while, it turns "sour". This is the result of fermentation: lactic acid bacteria turning the sugar inside the milk into lactic acid. This fermentation process is exploited in the production of various dairy products such as cheese and yogurt. There are four noted periods of milk decay:

• Rancid (also called "on the turn". Milk is still consumable at this stage)
• Curdling (separation of curd and whey will occur but may still be consumable)
• Coagulation (beyond use. A period of aromatic decay sets in accompanied by mould)
• Dry (beyond use. The milk has dehydrated and become hard and chalky)

Pasteurized cow's milk, on the other hand, spoils in a way that makes it unsuitable for consumption. This causes it to assume an unpleasant odor and pose a high danger of food poisoning if ingested. In raw milk, the naturally-occurring lactic acid bacteria, under suitable conditions, quickly produce large amounts of lactic acid. The ensuing acidity in turn prevents other germs from growing, or slows their growth significantly. Through pasteurization, however, these lactic acid bacteria are mostly destroyed, which means that other germs can grow unfettered and thus cause decomposition.

In order to prevent spoilage, milk can be kept refrigerated and stored between 1 and 4 degrees Celsius in bulk tanks. Most milk is pasteurized by heating briefly and then refrigerated to allow transport from factory farms to local markets. The spoilage of milk can be forestalled by using ultra-high temperature (UHT) treatment; milk so treated can be stored unrefrigerated for several months until opened. Sterilized milk, which is heated for a much longer period of time, will last even longer, but also lose more nutrients and assume a still different taste. Condensed milk, made by removing most of the water, can be stored in cans for many years, unrefrigerated, as can evaporated milk. The most durable form of milk is milk powder, which is produced from milk by removing almost all water.

Milk in language and culture

The importance of milk in human culture is attested to by the numerous expressions embedded in our languages, for example "the milk of human kindness", and the ways we have used it to name the visible world, for example the Milky Way.

Milk is drunk as an accompaniment to meals in North America, whereas Europeans, with the exception of North Europeans, do not habitually do so after childhood.

In African and Asian developing nations, butter is traditionally made from sour milk rather than cream. It can take several hours of churning to produce workable butter grains from fermented milk.^[20]

References

1. ^ FAO Food outlook: International dairy product prices are turning down: how far, how fast? FAO online publication, 1 June 2006
2. ^ Milk From Cows and Other Animals, web page by Washington Dairy Products Commission
3. ^ Diary Chemistry and Physics, webpage of University of Guelph
4. ^ Diary Chemistry and Physics, webpage of University of Guelph
5. ^ Raw Milk Vs. Pasteurized Milk. Reproduction from Armchair Science, London 1938.
6. ^ Homogenization of Milk and Milk Products, webpage of University of Guelph
7. ^ Density of milk
8. ^ Dairy's Role in Managing Blood Pressure, web page of the US National Diary Council
9. ^ Cohen, Rob. Your state's average pus count. Web page of the anti-diary Diary Education Board
10. ^ Greger, Michael. Paratuberculosis and Crohn's Disease: Got Milk? Pro-vegan online publication, January 2001
11. ^ Kahan, Z et al., Elevated levels of circulating insulin-like growth factor-I, IGF-binding globulin-3 and testosterone predict hormone-dependent breast cancer in postmenopausal women: a case-control study. Int J Oncol. 2006 Jul;29(1):193-200.
12. ^ Pacher, M. et al., Impact of constitutive IGF1/IGF2 stimulation on the transcriptional program of human breast cancer cells. Carcinogenesis. 2006 Jun 14
13. ^ International Scientific Committee Warns of Serious Risks of Breast and Prostate Cancer from Monsanto's Hormonal Milk. Press release of the Cancer Prevention Coalition.
14. ^ Milk: Epstein, S., America's Health Problem. Web page of the Cancer Prevention Coalition.
15. ^ Giovannucci, E. et al., Calcium and fructose intake in relation to risk of prostate cancer., Cancer Res. 1998 Feb 1;58(3):442-7.
16. ^ Chan, J.M., Dairy products, calcium, and prostate cancer risk in the Physicians' Health Study. Am J Clin Nutr. 2001 Oct;74(4):549-54. (disputed publication)
17. ^ Chan JM et al., (2005) Role of diet in prostate cancer development and progression. J Clin Oncol 23:8152-60.
18. ^ Calcium Rich Foods: Get All The Calcium You Need Without Milk
19. ^ Journal of the American College of Nutrition: Milk Consumption Does Not Lead to Mucus Production or Occurrence of Asthma
20. ^ Crawford et al, part B, section III, ch. 1: Butter. Retrieved 28 November 2005.

• McGee, Harold (2004). On Food and Cooking (Revised Edition). Scribner. ISBN 0-684-80001-2. 
• Introduction to Dairy Science and Technology: Milk History, Consumption, Production, and Composition
• Cow's Milk-Vegetarian or Non-vegetarian
• Milk
• How is Milk Made
• Milk Notes

• Milk: is it good or bad for us?

Wikipedia

http://en.wikipedia.org/w/index.php?title=Milk&action=history

http://www.gnu.org/copyleft/fdl.html