Milk bags are plastic bag

Plastic bag

A plastic bag, polybag, or pouch is a type of packaging made of thin, flexible, plastic film, nonwoven fabric, or plastic textile. Plastic bags are used for containing and transporting goods such as foods, produce, powders, ice, magazines, comic books, chemicals and waste.Most plastic bags are...

s that hold milk

Milk

Milk is a white liquid produced by the mammary glands of mammals. It is the primary source of nutrition for young mammals before they are able to digest other types of food. Early-lactation milk contains colostrum, which carries the mother's antibodies to the baby and can reduce the risk of many...

. They are usually stored in a pitcher

Pitcher (container)

A pitcher is a container with a spout used for storing and pouring contents which are liquid in form. Generally a pitcher also has a handle, which makes pouring easier.A ewer is a vase-shaped pitcher, often decorated, with a base and a flaring spout...

 or jug

Jug (container)

A jug is a type of container used to hold liquid. It has an opening, often narrow, from which to pour or drink, and nearly always has a handle. One could imagine a jug being made from nearly any watertight material, but most jugs throughout history have been made from clay, glass, or plastic...

 with one of the corners cut off to allow for pouring. A typical milk bag contains approximately 1 1/3 litres of milk.

Popularity

Milk bags are common in several countries and regions of the world, including Argentina

Argentina

Argentina , officially the Argentine Republic , is the second largest country in South America by land area, after Brazil. It is constituted as a federation of 23 provinces and an autonomous city, Buenos Aires...

, Bolivia

Bolivia

Bolivia officially known as Plurinational State of Bolivia , is a landlocked country in central South America. It is the poorest country in South America...

, Brazil

Brazil

Brazil , officially the Federative Republic of Brazil , is the largest country in South America. It is the world's fifth largest country, both by geographical area and by population with over 192 million people...

, Nicaragua

Nicaragua

Nicaragua is the largest country in the Central American American isthmus, bordered by Honduras to the north and Costa Rica to the south. The country is situated between 11 and 14 degrees north of the Equator in the Northern Hemisphere, which places it entirely within the tropics. The Pacific Ocean...

, Honduras

Honduras

Honduras is a republic in Central America. It was previously known as Spanish Honduras to differentiate it from British Honduras, which became the modern-day state of Belize...

, Canada

Canada

Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...

, China

China

Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...

, Colombia

Colombia

Colombia, officially the Republic of Colombia , is a unitary constitutional republic comprising thirty-two departments. The country is located in northwestern South America, bordered to the east by Venezuela and Brazil; to the south by Ecuador and Peru; to the north by the Caribbean Sea; to the...

, Estonia

Estonia

Estonia , officially the Republic of Estonia , is a state in the Baltic region of Northern Europe. It is bordered to the north by the Gulf of Finland, to the west by the Baltic Sea, to the south by Latvia , and to the east by Lake Peipsi and the Russian Federation . Across the Baltic Sea lies...

, Hungary

Hungary

Hungary , officially the Republic of Hungary , is a landlocked country in Central Europe. It is situated in the Carpathian Basin and is bordered by Slovakia to the north, Ukraine and Romania to the east, Serbia and Croatia to the south, Slovenia to the southwest and Austria to the west. The...

, India

India

India , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...

, Iran

Iran

Iran , officially the Islamic Republic of Iran , is a country in Southern and Western Asia. The name "Iran" has been in use natively since the Sassanian era and came into use internationally in 1935, before which the country was known to the Western world as Persia...

, Israel

Israel

The State of Israel is a parliamentary republic located in the Middle East, along the eastern shore of the Mediterranean Sea...

, Montenegro

Montenegro

Montenegro Montenegrin: Crna Gora Црна Гора , meaning "Black Mountain") is a country located in Southeastern Europe. It has a coast on the Adriatic Sea to the south-west and is bordered by Croatia to the west, Bosnia and Herzegovina to the northwest, Serbia to the northeast and Albania to the...

, Poland

Poland

Poland , officially the Republic of Poland , is a country in Central Europe bordered by Germany to the west; the Czech Republic and Slovakia to the south; Ukraine, Belarus and Lithuania to the east; and the Baltic Sea and Kaliningrad Oblast, a Russian exclave, to the north...

, South Africa

South Africa

The Republic of South Africa is a country in southern Africa. Located at the southern tip of Africa, it is divided into nine provinces, with of coastline on the Atlantic and Indian oceans...

, New Zealand

New Zealand

New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...

 and Uruguay

Uruguay

Uruguay ,officially the Oriental Republic of Uruguay,sometimes the Eastern Republic of Uruguay; ) is a country in the southeastern part of South America. It is home to some 3.5 million people, of whom 1.8 million live in the capital Montevideo and its metropolitan area...

. They were also common in Bulgaria

Bulgaria

Bulgaria , officially the Republic of Bulgaria , is a parliamentary democracy within a unitary constitutional republic in Southeast Europe. The country borders Romania to the north, Serbia and Macedonia to the west, Greece and Turkey to the south, as well as the Black Sea to the east...

 and other Balkan

Balkans

The Balkans is a geopolitical and cultural region of southeastern Europe...

 countries during the Soviet bloc period, but their popularity diminished in subsequent years. Declining popularity in this region is attributed to the lower shelf appeal of the milk bags compared to others emerging at the time such as Tetra Pak

Tetra Pak

Tetra Pak is a multinational food processing and packaging company of Swedish origin. It was founded in 1951 in Lund, Sweden, by Ruben Rausing. It was Erik Wallenberg who invented the tetrahedral package, today known as Tetra Classic...

 and plastic bottle

Plastic bottle

A plastic bottle is a bottle constructed of plastic, with a neck that is narrower than its real body and an opening at the top. The mouth of the bottle is normally sealed with a plastic bottle cap. Plastic bottles are typically used to store liquids such as water, soft drinks, motor oil, cooking...

s. A resurgence of milk bags is beginning in Britain amid concerns that plastic bottles aren't being recycled. Milk bags were also used in Australia (Greater Shepparton, Victoria), in the late 1990s, distributed by Shepparton-based dairy company Ducats. Some dairies in the United States used the bags in the 1980s, but today are confined mainly to regional convenience store

Convenience store

A convenience store, corner store, corner shop, commonly called a bodega in Spanish-speaking areas of the United States, is a small store or shop in a built up area that stocks a range of everyday items such as groceries, toiletries, alcoholic and soft drinks, and may also offer money order and...

 chains with in-house dairies such as Kwik Trip

Kwik Trip

Kwik Trip/Kwik Star is a chain of convenience stores founded in 1965 with locations throughout Wisconsin and Minnesota under the name Kwik Trip, and in northeast Iowa under the name Kwik Star . The company also operates stores under the name Hearty Platter and Tobacco Outlet Plus. Kwik Trip, Inc...

 in the Upper Midwest

Upper Midwest

The Upper Midwest is a region in the northern portion of the U.S. Census Bureau's Midwestern United States. It is largely a sub-region of the midwest. Although there are no uniformly agreed-upon boundaries, the region is most commonly used to refer to the states of Minnesota, Wisconsin, and...

 and other boutique dairies.

In the United Kingdom

United Kingdom

The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...

, Sainsburys began a pilot experiment on distributing milk in bags in 2008 in conjunction with Dairy Crest

Dairy Crest

Dairy Crest Group plc is a major dairy products company in the United Kingdom. Its brands include Cathedral City Cheddar cheese, Utterly Butterly, Vitalite, Clover, St Ivel and Frijj. The company delivers milk to around 1.1 million households via their milkmen...

. It was originally targeted at 35 stores at the same price as a regular 2 pints (1.1 l) plastic bottle of milk, the product was expanded nationwide in 2010 at which point the bags retailed at a discounted price compared to traditional containers.

Benefits

Milk bags use less plastic than traditional milk jugs and are placed in reusable plastic pitchers. The bags themselves can also be washed out and re-used to carry sandwiches, or to freeze food (using a twist tie or rubber band for closure). Because they are designed to be watertight, they are more durable than most commercially available sandwich bags.

Drawbacks

Milk bags sometimes puncture or burst, are weaker than milk jugs, and have thin linings. When pouring, the top of the bag can also topple over, causing the milk to spill. Spillage can be avoided by cutting a secondary hole at the other side of the bag for air intake, by pinching the top of the bag while pouring, or by using a pitcher with a lid to keep the milk bag in place.
Milk bags cannot be sealed once open, although some consumers fold over the spout and use clips to help maintain freshness.