Plastic milk containers are plastic containers for storing, shipping and dispensing milk. Plastic bottles, sometimes called jugs, have largely replaced glass bottles for home consumption. Glass milk bottles have traditionally been reusable while light-weight plastic bottles are designed for single trips and plastic recycling.
Packaging of milk is regulated by regional authorities. Use of food contact materials is required: potential food contamination is prohibited. Strict standards of cleanliness and processing must be followed.
The most common material in milk packaging is high density polyethylene (HDPE), recycling code 2. Low density polyethylene (LDPE) and polyester (PET) [1] are also in use. Polycarbonate had been considered but had concerns about potential contamination with bisphenol A. [2]
Blow molded plastic milk bottles have been in use since the 1960s. [3] [4] [5] HDPE is the primary material, but polyester is also used. A wide variety of milk bottle designs are available. Some have a round cross section while others have a more square or rectangular shape. A special flat-top square milk jug was recently[ when? ] developed to maximize shipping and storing efficiency but had some difficulties in dispensing. Many milk bottles have integral handles.
Milk bags are also in use. The milk is sold in a plastic bag and put into a pitcher for use. Larger bags are the inner bladder of a bag-in-box, sometimes used for institutional dispensing.
Small individual containers of milk and cream are often thermoformed or injection molded and have a peelable lid. These are often used in restaurants.
The shelf life of pasteurized milk in HDPE bottles and LDPE pouches has been determined to be between 10 and 21 days when stored at 4–8 °C. Other factors such as light and temperature abuse have effects. Shelf life can be extended by ultrapasteurisation and aseptic processing. [6] [7]
Milk containers for retail sale must contain the same amount of milk as indicated on the label. To be acceptable to consumers, the containers must also appear to be completely full. Therefore, the volume of the container must be precisely controlled.
The designer of a die for a blow moulded bottle can never be completely sure of how much the finished bottle will hold. Shrinkage always occurs after the item is released from the mould. The amount of shrinkage depends upon many factors, including cycle time, inflation air pressure, time in storage prior to filling, storage temperature, and more.
A volume adjuster insert is one way to slightly adjust the volume of a bottle, without building a completely new mould. A volume insert attaches to the inside of a mould, creating a circular indentation on the side of the finished bottle. Different size inserts can be used as manufacturing circumstances change, for example mould temperature or cooling rate. The volume of finished bottles is periodically measured, and volume inserts are changed as needed. [8]
Many potential factors are involved in environmental comparisons of returnable vs non-returnable systems. Researchers have often used life cycle analysis methodologies to balance the many diverse considerations. Often the comparisons show benefits and problems with all alternatives. [9] [10] One recent life cycle study of one-way recyclable HDPE bottles indicated the importance of secondary packaging: returnable plastic crates can allow lower tare weight bottles. [11]
Reuse of bottles requires a reverse logistics system, cleaning and sanitizing bottles, and an effective quality management system. A key factor with glass milk bottles is the number of cycles of uses to be expected. Breakage, contamination, or other loss reduces the benefits of returnables. A key factor with one-way recyclables is the recycling rate: In the US, only about 30–35% of HDPE bottles are recycled. [12]
The Resin Identification Code (RIC) is a technical standard with a set of symbols appearing on plastic products that identify the plastic resin out of which the product is made. It was developed in 1988 by the Society of the Plastics Industry in the United States, but since 2008 it has been administered by ASTM International, an international standards organization.
A thermoplastic, or thermosofteningplastic, is any plastic polymer material that becomes pliable or moldable at a certain elevated temperature and solidifies upon cooling.
A reusable bottle is a bottle that can be reused, as in the case as by the original bottler or by end-use consumers. Reusable bottles have grown in popularity by consumers for both environmental and health safety reasons. Reusable bottles are one example of reusable packaging.
Nalgene is a brand of plastic products developed originally for laboratory use, including items such as jars, bottles, test tubes, and Petri dishes, that were shatterproof and lighter than glass. The properties of plastic products make them suitable for work with many substances in various temperature ranges.
A closure is a device used to close or seal a container such as a bottle, jug, jar, tube, or can. A closure may be a cap, cover, lid, plug, liner, or the like. The part of the container to which the closure is applied is called the finish.
A plastic bag, poly bag, or pouch is a type of container 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, chemicals, and waste. It is a common form of packaging.
High-density polyethylene (HDPE) or polyethylene high-density (PEHD) is a thermoplastic polymer produced from the monomer ethylene. It is sometimes called "alkathene" or "polythene" when used for HDPE pipes. With a high strength-to-density ratio, HDPE is used in the production of plastic bottles, corrosion-resistant piping, geomembranes and plastic lumber. HDPE is commonly recycled, and has the number "2" as its resin identification code.
A water bottle is a container that is used to hold liquids, mainly water, for the purpose of transporting a drink while travelling or while otherwise away from a supply of potable water.
Low-density polyethylene (LDPE) is a thermoplastic made from the monomer ethylene. It was the first grade of polyethylene, produced in 1933 by Dr John C. Swallow and M.W Perrin who were working for Imperial Chemical Industries (ICI) using a high pressure process via free radical polymerization. Its manufacture employs the same method today. The EPA estimates 5.7% of LDPE is recycled in the United States. Despite competition from more modern polymers, LDPE continues to be an important plastic grade. In 2013 the worldwide LDPE market reached a volume of about US$33 billion.
Glass milk bottles are glass bottles used for milk. They are reusable and returnable – used mainly for doorstep delivery of fresh milk by milkmen. Once customers have finished the milk, empty bottles are expected to be rinsed and left on the doorstep for collection, or rinsed bottles may be returned to a participating retail store. Bottle sizes vary depending on region, but common sizes include pint, quart or litre.
A glass bottle is a bottle made from glass. Glass bottles can vary in size considerably, but are most commonly found in sizes ranging between about 200 millilitres and 1.5 litres. Common uses for glass bottles include food condiments, soda, liquor, cosmetics, pickling and preservatives; they are occasionally also notably used for the informal distribution of notes. These types of bottles are utilitarian and serve a purpose in commercial industries.
A plastic bottle is a bottle constructed from high-density or low density plastic. Plastic bottles are typically used to store liquids such as water, soft drinks, motor oil, cooking oil, medicine, shampoo or milk. They range in sizes, from very small bottles to large carboys. Consumer blow molded containers often have integral handles or are shaped to facilitate grasping.
A milk bag is a flexible plastic pouch used to package milk and is used in some areas instead of a hardened milk jug, or as an alternative to it. Usually one of the corners is cut off to allow for pouring, and the bag is stored in a pitcher.
Plastics are a wide range of synthetic or semi-synthetic materials that use polymers as a main ingredient. Their plasticity makes it possible for plastics to be molded, extruded or pressed into solid objects of various shapes. This adaptability, plus a wide range of other properties, such as being lightweight, durable, flexible, and inexpensive to produce, has led to their widespread use. Plastics typically are made through human industrial systems. Most modern plastics are derived from fossil fuel-based chemicals like natural gas or petroleum; however, recent industrial methods use variants made from renewable materials, such as corn or cotton derivatives.
Ecologic Brands Inc. is a United States company that specializes in creating eco-friendly packaging for consumer products. The products are made from sustainable materials and are designed to be recyclable or compostable. The company also provides branding and marketing services to help companies promote their environmentally conscious products.
Bottles are able to be recycled and this is generally a positive option. Bottles are collected via kerbside collection or returned using a bottle deposit system. Currently just over half of plastic bottles are recycled globally. About 1 million plastic bottles are bought around the world every minute and only about 50% are recycled.
Reusable packaging is manufactured of durable materials and is specifically designed for multiple trips and extended life. A reusable package or container is "designed for reuse without impairment of its protective function." The term returnable is sometimes used interchangeably but it can also include returning packages or components for other than reuse: recycling, disposal, incineration, etc. Typically, the materials used to make returnable packaging include steel, wood, polypropylene sheets or other plastic materials.
The history of bottle recycling in the United States has been characterized by four distinct stages. In the first stage, during the late 18th century and early 19th century, most bottles were reused or returned. When bottles were mass-produced, people started throwing them out, which led to the introduction of bottle deposits. However, during the second stage, after World War II, consumption patterns changed and nonreturnable containers became popular, which littered the environment. Some states implemented "bottle bills" that instituted deposits. The beverage-container industry first implemented private recycling programs and then pushed for municipal curbside recycling as an alternative to "bottle bills". More recently, PET bottles have largely replaced other materials. The United States used to be the front-runner when it came to recycling PET, but European countries have since outpaced the US.
Packaging waste, the part of the waste that consists of packaging and packaging material, is a major part of the total global waste, and the major part of the packaging waste consists of single-use plastic food packaging, a hallmark of throwaway culture. Notable examples for which the need for regulation was recognized early, are "containers of liquids for human consumption", i.e. plastic bottles and the like. In Europe, the Germans top the list of packaging waste producers with more than 220 kilos of packaging per capita.
Multi-layered packaging are multilayer or composite materials using innovative technologies aimed to give barrier properties, strength and storage stability to food items, new materials as well as hazardous materials.