Microwave popcorn is a convenience food consisting of unpopped popcorn in an enhanced, sealed paper bag intended to be heated in a microwave oven. In addition to the dried corn, the bags typically contain cooking oil with sufficient saturated fat to solidify at room temperature, one or more seasonings (often salt), and natural or artificial flavorings or both.
The bag is typically partially folded when it is placed in a microwave, and inflates as a result of steam pressure from the heated kernels.
Microwave popcorn bags are designed to avoid popped-kernel scorching, an undesirable effect that takes place when popped kernels are heated above 300 °F (150 °C). [1] A susceptor—usually a metalized film laminated onto the paper of the bag—absorbs microwaves and concentrates heat at the film interface, thus ensuring a heat distribution focused on the hard-to-heat flavor coating so that the unpopped kernels are evenly coated prior to popping, thereby ensuring even flavor throughout the product.
Some popcorn is flawed and will not pop because of possible damage to the shell, which allows the steam to escape. These unpopped kernels are known as "old maids" or "spinsters". [2]
An early susceptor popcorn bag design was patented by the American company General Mills in 1981 (US Patent #4,267,420). [3]
Care in package design is needed for food safety. [4]
A safety issue is that the cooking time given on the packaging does not apply to all microwave ovens. Setting the timer and coming back later, after the timer's alarm has sounded, could result in the popcorn being burnt and smoking badly. Microwave popcorn makers suggest that the person cooking the popcorn stay near the oven to observe the popcorn as it cooks, and take the popcorn out when the time between pops is more than a few seconds.
Some microwave ovens have a specific mode designed for cooking popcorn, which either uses factory-calibrated time and power level settings, or which uses humidity or sound sensors to detect when popping has finished. [5] [6]
The concern about microwave popcorn bags has increased in terms of the waste and their harmful impacts on the environment. The coating materials used in microwave popcorn bags can have negative effects on the environment. Researchers have detected toxic chemicals in the bags, such as perfluorinated compounds (PFCs) and their potential precursors.
Researchers have detected many PFCs in microwave popcorn bags used as coating materials for oil and moisture resistance. The amount of PFOA in some microwave popcorn bags is determined as high as 300 μg kg−1. [7] Besides PFOA and PFOS, Moral et al. also determined other perfluorocarboxylic acids (PFCAs) in popcorn packaging, including perfluoroheptanoic (PFHpA), perfluorononanoic (PFNA), perfluorodecanoic (PFDA), perfluoroundecanoic (PFUnA), and perfluorododecanoic (PFDoA) acids. [8]
Due to the toxicity of PFOA, major U.S. manufacturers volunteered to phase out production of PFOA by the end of 2015. In addition, the use of perfluoroalkyl ethyl-containing food-contact substances are no longer allowed by the U.S Food and Drug Administration (FDA) regulations in January 2016. [9] However, although the production of PFOA and PFOS was reduced, the production of fluorotelomer-based chemicals applied to food contact papers is still increasing. Some compounds, such as polyfluoroalkyl phosphate surfactants (PAPs) or fluorotelomers (FTOH), have been used in some brands of microwave popcorn bags. [8] Those compounds are precursors of PFCAs, and evidence shows that they are more toxic than PFCAs themselves. Furthermore, they may also be degraded to PFCAs, and therefore leading to the increase of PFCAs concentrations in the environment and generating adverse effects. [8] [10]
Because of the large amount of production of microwave popcorn bags, they have also become a significant contaminant source (PFCs) to the environment. Due to the disposal of coated paper and manufacturing activities, PFOA has also been detected in wastewater and biosolids. [11] Soil near disposal sites are contaminated by PFOA as well. [12]
Polytetrafluoroethylene (PTFE) is a synthetic fluoropolymer of tetrafluoroethylene and is a PFAS that has numerous applications. The commonly known brand name of PTFE-based composition is Teflon by Chemours, a spin-off from DuPont, which originally discovered the compound in 1938.
Perfluorooctanoic acid is a perfluorinated carboxylic acid produced and used worldwide as an industrial surfactant in chemical processes and as a material feedstock. PFOA is considered a surfactant, or fluorosurfactant, due to its chemical structure, which consists of a perfluorinated, n-heptyl "tail group" and a carboxylate "head group". The head group can be described as hydrophilic while the fluorocarbon tail is both hydrophobic and lipophobic.
Perfluorooctanesulfonic acid (PFOS) is a chemical compound having an eight-carbon fluorocarbon chain and a sulfonic acid functional group and thus a perfluorosulfonic acid. It is an anthropogenic (man-made) fluorosurfactant, now regarded as a global pollutant. PFOS was the key ingredient in Scotchgard, a fabric protector made by 3M, and related stain repellents. The acronym "PFOS" refers to the parent sulfonic acid and to various salts of perfluorooctanesulfonate. These are all colorless or white, water-soluble solids. Although of low acute toxicity, PFOS has attracted much attention for its pervasiveness and environmental impact. It was added to Annex B of the Stockholm Convention on Persistent Organic Pollutants in May 2009.
Scotchgard is a 3M brand of products, a stain and durable water repellent applied to fabric, furniture, and carpets to protect them from stains. Scotchgard products typically rely on organofluorine chemicals as the main active ingredient along with petroleum distillate solvents.
Perfluorononanoic acid, or PFNA, is a synthetic perfluorinated carboxylic acid and fluorosurfactant that is also an environmental contaminant found in people and wildlife along with PFOS and PFOA.
Per- and polyfluoroalkyl substances (PFAS or PFASs) are a group of synthetic organofluorine chemical compounds that have multiple fluorine atoms attached to an alkyl chain. An early definition, from 2011, required that they contain at least one perfluoroalkyl moiety, –CnF2n+1–. Beginning in 2021, the Organisation for Economic Co-operation and Development (OECD) expanded their terminology, stating that "PFASs are defined as fluorinated substances that contain at least one fully fluorinated methyl or methylene carbon atom (without any H/Cl/Br/I atom attached to it), i.e., with a few noted exceptions, any chemical with at least a perfluorinated methyl group (–CF3) or a perfluorinated methylene group (–CF2–) is a PFAS."
Fluorotelomer alcohols, or FTOHs, are fluorotelomers with an alcohol functional group. They are volatile precursors to perfluorinated carboxylic acids, such as PFOA and PFNA, and other compounds.
Perfluorobutanesulfonic acid (PFBS) is a PFAS chemical compound having a four-carbon fluorocarbon chain and a sulfonic acid functional group. It is stable and unreactive because of the strength of carbon–fluorine bonds. It can occur in the form of a colorless liquid or a corrosive solid. Its conjugate base is perfluorobutanesulfonate which functions as the hydrophobe in fluorosurfactants.
Fluorotelomers are fluorocarbon-based oligomers, or telomers, synthesized by telomerization. Some fluorotelomers and fluorotelomer-based compounds are a source of environmentally persistent perfluorinated carboxylic acids such as PFOA and PFNA, while others are under extended investigation.
A perfluorinated compound (PFC) or perfluoro compound is an organofluorine compound lacking C-H bonds. Many perfluorinated compounds have properties that are quite different from their C-H containing analogues. Common functional groups in PFCs are OH, CO2H, chlorine, O, and SO3H. Electrofluorination is the predominant method for their production. Due to their chemical stability, some of these perfluorinated compounds bioaccumulate.
Perfluoroalkyl carboxylic acids (PFCAs), or perfluorocarboxylic acids are compounds of the formula CnF(2n+1)CO2H that belong to the class of per- and polyfluoroalkyl substances. The simplest example is trifluoroacetic acid. These compounds are organofluorine analogues of ordinary carboxylic acids, but they are stronger by several pKa units and they exhibit great hydrophobic character. Perfluoroalkyl dicarboxylic acids (PFdiCAs) are also known, e.g. C2F4(CO2H)2.
Perfluorooctanesulfonamide (PFOSA) is a synthetic organofluorine compound. It is a fluorocarbon derivative and a perfluorinated compound, having an eight-carbon chain and a terminal sulfonamide functional group. PFOSA, a persistent organic pollutant, was an ingredient in 3M's former Scotchgard formulation from 1956 until 2003, and the compound was used to repel grease and water in food packaging along with other consumer applications. It breaks down to form perfluorooctane sulfonate (PFOS). The perfluorooctanesulfonyl fluoride-based chemistry that was used to make sulfonamides like PFOSA was phased out by 3M in the United States (US) during 2000–2002 but it has grown in China by other producers.
Perfluorooctanesulfonyl fluoride (POSF) is a synthetic perfluorinated compound with a sulfonyl fluoride functional group. It is used to make perfluorooctanesulfonic acid (PFOS) and PFOS-based compounds. These compounds have a variety of industrial and consumer uses, but POSF-derived substances ultimately degrade to form PFOS.
The Devil We Know is a 2018 investigative documentary film by director Stephanie Soechtig regarding allegations of health hazards from perfluorooctanoic acid, a key ingredient used in manufacturing Teflon, and DuPont's potential responsibility. PFAS are commonly found in every household, and in products as diverse as non-stick cookware, stain resistant furniture and carpets, wrinkle free and water repellant clothing, cosmetics, lubricants, paint, pizza boxes, popcorn bags, and many other everyday products.
Fluorine may interact with biological systems in the form of fluorine-containing compounds. Though elemental fluorine (F2) is very rare in everyday life, fluorine-containing compounds such as fluorite occur naturally as minerals. Naturally occurring organofluorine compounds are extremely rare. Man-made fluoride compounds are common and are used in medicines, pesticides, and materials. Twenty percent of all commercialized pharmaceuticals contain fluorine, including Lipitor and Prozac. In many contexts, fluorine-containing compounds are harmless or even beneficial to living organisms; in others, they are toxic.
Water contamination in Lawrence and Morgan Counties, Alabama, revolves around the presence of perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) in the water supply. After the US Environmental Protection Agency (EPA) released new health advisories in March 2016, there was concern over health risks of the levels of PFOA and PFOS present. The responses of different government officials, agencies, and companies raise questions as to whether or not there was any environmental injustice involved.
GenX is a Chemours trademark name for a synthetic, short-chain organofluorine chemical compound, the ammonium salt of hexafluoropropylene oxide dimer acid (HFPO-DA). It can also be used more informally to refer to the group of related fluorochemicals that are used to produce GenX. DuPont began the commercial development of GenX in 2009 as a replacement for perfluorooctanoic acid.
This timeline of events related to per- and polyfluoroalkyl substances (PFASs) includes events related to the discovery, development, manufacture, marketing, uses, concerns, litigation, regulation, and legislation, involving the human-made PFASs. The timeline focuses on some perfluorinated compounds, particularly perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) and on the companies that manufactured and marketed them, mainly DuPont and 3M. An example of PFAS is the fluorinated polymer polytetrafluoroethylene (PTFE), which has been produced and marketed by DuPont under its trademark Teflon. GenX chemicals and perfluorobutanesulfonic acid (PFBS) are organofluorine chemicals used as a replacement for PFOA and PFOS.
Perfluorohexanesulfonic acid (PFHxS) is a synthetic chemical compound. It is one of many compounds collectively known as per- and polyfluoroalkyl substances (PFASs). It is an anionic fluorosurfactant and a persistent organic pollutant with bioaccumulative properties. Although the use of products containing PFHxS and other PFASs have been banned or are being phased out in many jurisdictions, it remains ubiquitous in many environments and within the general population, and is one of the most commonly detected PFASs.
