Foam food container
A foam food container is a form of disposable food packaging for various foods and beverages, such as processed instant noodles, raw meat from supermarkets, ice cream from ice cream parlors, cooked food from delicatessens or food stalls, or beverages like "coffee to go". They are also commonly used to serve takeout food from restaurants, and are also available by request for diners who wish to take home the remainder of their meal . The foam is a good thermal insulator, making the container easy to carry as well as keeping the food at the temperature it had when filled into the container, whether hot or cold.
Construction and composition
Foam take-out containers are made from EPS foam, or another type of polystyrene foam, and produced by injecting the foam into a mold. They are usually white in color, although they may be printed or impressed with a company logo or other message.
Incorrectly referred to as Styrofoam, which is a trademark of The Dow Chemical Company for closed-cell extruded polystyrene foam currently made for thermal insulation and craft applications. The term is often incorrectly used as a generic term for expanded (not extruded) polystyrene foam, such as disposable coffee cups, coolers, or cushioning material in packaging, which are typically white and made of expanded polystyrene beads.
This is a different material from the extruded polystyrene used for Styrofoam house insulation. The polystyrene foam used for craft applications, which can be identified by its roughness and by the fact that it "crunches" when cut, is moderately soluble in many organic solvents, cyanoacrylate, and the propellants and solvents of spray paint, and is not specifically identified as expanded or extruded. Another tradename for expanded polystyrene is thermacol, originated by BASF.
The different varieties of foam takeout containers may include:
- A rectangular shaped clamshell style container with an attached lid, which comes in various sizes. The larger ones usually feature several compartments, allowing different foods to be kept separated from each other. This variety usually features several small projections on the lid of the container, which fit through slots on the bottom half to "lock" it, therefore keeping the cover closed. These containers are leak-resistant only if kept upright, and often have a square imprint area for labeling.
- A cylindrical style container with a separate, translucent or opaque plastic lid which can seal tightly to resist leaks. The container may or may not taper somewhat towards the bottom. Both overall size and the ratio of height to diameter can vary greatly. Such containers usually hold soups and stews; however, smaller varieties are often used to hold sauces and condiments.
Foam containers are the most commonly used takeout box for Chinese cuisines in East and Southeast Asia. It is standard for Cantonese cuisine in Hong Kong and many parts of China and sometimes used overseas in various restaurants, particularly in the United States and Canada.
Foam takeout containers entirely made out of polystyrene foam affect the environment as they do not biodegrade easily. However, microbial degradation of styrene via methanogens has been investigated and confirmed, intermediate products being various organic substances and carbon dioxide. Pseudomonas putida can also convert styrene oil into various biodegradable polyhydroxyalkanoates. Some cities have banned the use of foam take-out containers, notably San Francisco, Seattle and Portland, Oregon. In 2013, the mayor of New York City proposed banning foam food containers for both health and environmental reasons. Implementation of this plan began in early 2015, but a September 2015 court ruling has since put the ban on hold.
It is debated whether styrene may migrate into food which is stored in foam food containers for even a short time. Some researchers argue that polystyrene containers pose a health risk, while industry defenders argue that trace amounts of styrene are already naturally present in food. Styrene foam containers can melt if the food or liquid is of a sufficiently high temperature. Some containers have been tested and labelled for safe use in microwave ovens, although the absence of such labeling does not mean a container is unsafe for this use; caution should still be taken.
Styrene is considered by both the EPA and IARC to be a possible carcinogen. It poses a health risk to workers involved in the production of styrene and polystyrene items, and industries have a compliance program to deal with liabilities. Prolonged exposure to high amounts of styrene may affect the central nervous system, causing diseases like Parkinson's disease and multiple sclerosis.
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