Cartons of Milk, Industry Sector BEVERAGES

Milk is made up of over 80% water. Cow and goat milk is 87% water, and sheep milk is 83% water. The remaining percentage of milk is made up of milk fat, milk sugar (lactose), milk protein (primarily casein) vitamins, minerals, and other trace elements.

HISTORY OF MILK PROCESSING

Louis Pasteur

1856 French chemist Louis Pasteur began his experiments that would lead to his development of pasteurization, the process that destroys harmful microbes found in perishable food products without damaging the food itself.

1878 Dr. Gustav De Laval of Sweden invented the continuous centrifugal cream separator that was used by large dairies around the world.

1884 Dr. Hervey D. Thatcher of Potsdam, New York invented the milk bottle.

1886 The automatic bottle filler and capper was patented in the United States

1895 Commercial pasteurizing machines were introduced.

1911 The automatic rotary bottle filler and capper was perfected

1914 Tank trucks first rolled out to transport milk.

1919 Homogenized milk was first successfully sold in Torrington, Connecticut

1932 The first plastic coated paper milk cartons are introduced commercially

1948 Ultra-high temperature pasteurization is introduced

1950 Milk vending machines begin distribution.

1964 The plastic milk container is launched.

1968 Electronic testing for milk is introduced commercially, marking the official acceptance of the process.

FROM FARM TO TABLE

Storage at the farm

Milk storage vats or silos are refrigerated and come in various shapes and sizes. Milk is stored on the farm at 4 degrees Celsius for no longer than 48 hours. Vats and silos are agitated to make sure that the entire volume remains cold and milk fat does not separate from the milk.

Transportation to the dairy

Milk is collected from the farm every 24 or 48 hours. The tankers that are used have a special stainless steel body which are heavily insulated to keep the milk cold during transportation to the processing factory. Milk tanker drivers are accredited milk graders, which allows them to evaluate the milk prior to collection. Tanker drivers grade and if necessary reject milk based on temperature, sight and smell.  A representative sample is collected from each farm pickup prior to being pumped onto the tanker. After collection, milk is transported to dairies and stored in refrigerated silos before being processing.

Laboratory testing

Samples of milk are taken from farm vats prior to collection and from the bulk milk tanker on arrival at the factory. Samples from the bulk milk tanker are tested for contaminants and temperature before the milk enters the dairy.  Farm milk samples are tested for milkfat/protein/bulk milk cell count and bacteria count.  Most farmers are paid on quality and composition of their milk and it is extremely important that these samples are collected and stored correctly.

Pasteurization

There are two widely used methods to pasteurize milk: high temperature/short time (HTST), and ultra-high temperature (UHT). HTST is by far the most common method. Milk simply labelled "pasteurized" is usually treated with the HTST method, whereas milk labelled "ultra-pasteurized" must be treated with the UHT method. HTST involves holding the milk at a temperature of 161.5 degrees Fahrenheit (or 72 degrees Celsius) for at least 15 seconds. UHT involves holding the milk at a temperature of 280 °F or 138 °C for at least two seconds.

Homogenization

This involves pushing the raw milk through an atomizer to form tiny particles so that the fat is dispersed evenly throughout the milk, stopping the fat from floating to the top of the container.

Packaging

Drinking milk is then packaged. As plastic coated paper cartons (one or two litres) move along a conveyer belt beneath the filling machine, milk is automatically released into them. Another section of the machine heat-seals the cartons. The filled and sealed carton then passes along the production line to a date stamping machine.  

Crazy Facts Corner

·         A few years ago the New Zealand government passed a law restricting supermarkets from selling milk unless it was flavoured. The idea was to protect the small shopkeepers. The supermarkets hit back by selling “milk flavoured milk” and the law was repealed.

·         In 1967 John Johnson from Minnesota USA claimed the milk-drinking record. He downed 3 ½ gallons in an hour.

·         Milk carton boat racing is now a popular though slightly crazy pastime.

·         Milk remains fresh for 7-10 days after the expiration date if refrigerated at 35-40°F. Each 5° (F) rise in temperature shortens milk's shelf life by 50% because of bacteria growth.

Links:

http://www.pauls.com.au/information/information.cfm?/section/3/subsection/22/#s6

http://www.lanimoo.com/products/learn.asp

http://en.wikipedia.org/wiki/Pasteurization

Researched by Dynamic Dave