Carrageenans or carrageenins ( ; ) are a family of natural linear

sulfated Sulfation (sometimes spelled sulphation in British English) is the chemical reaction that entails the addition of SO3 group. In principle, many sulfations would involve reactions of sulfur trioxide (SO3). In practice, most sulfations are effected ...

polysaccharide Polysaccharides (), or polycarbohydrates, are the most abundant carbohydrates found in food. They are long-chain polymeric carbohydrates composed of monosaccharide units bound together by glycosidic linkages. This carbohydrate can react with wat ...

s. They are extracted from

red Red is the color at the long wavelength end of the visible spectrum of light, next to orange and opposite violet. It has a dominant wavelength of approximately 625–750 nanometres. It is a primary color in the RGB color model and a seconda ...

edible seaweed Edible seaweed, or sea vegetables, are seaweeds that can be eaten and used for culinary purposes. They typically contain high amounts of fiber. They may belong to one of several groups of multicellular algae: the red algae, green algae, and bro ...

s. Carrageenans are widely used in the

food industry The food industry is a complex, global network of diverse businesses that supplies most of the food consumed by the world's population. The food industry today has become highly diversified, with manufacturing ranging from small, traditional, ...

, for their gelling, thickening, and stabilizing properties. Their main application is in dairy and meat products, due to their strong binding to food proteins. Carrageenans have emerged as a promising candidate in

tissue engineering Tissue engineering is a biomedical engineering discipline that uses a combination of cells, engineering, materials methods, and suitable biochemical and physicochemical factors to restore, maintain, improve, or replace different types of biolo ...

and regenerative medicine applications as they resemble animal

glycosaminoglycan Glycosaminoglycans (GAGs) or mucopolysaccharides are long, linear polysaccharides consisting of repeating disaccharide units (i.e. two-sugar units). The repeating two-sugar unit consists of a uronic sugar and an amino sugar, except in the case o ...

s (GAGs). They are used for

, wound coverage, and

drug delivery Drug delivery involves various methods and technologies designed to transport pharmaceutical compounds to their target sites helping therapeutic effect. It involves principles related to drug preparation, route of administration, site-specif ...

. Carrageenans contain 15–40%

ester In chemistry, an ester is a compound derived from an acid (either organic or inorganic) in which the hydrogen atom (H) of at least one acidic hydroxyl group () of that acid is replaced by an organyl group (R). These compounds contain a distin ...

sulfate The sulfate or sulphate ion is a polyatomic anion with the empirical formula . Salts, acid derivatives, and peroxides of sulfate are widely used in industry. Sulfates occur widely in everyday life. Sulfates are salts of sulfuric acid and many ...

content, which makes them

anionic An ion () is an atom or molecule with a net electrical charge. The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by convent ...

polysaccharides. They can be mainly categorized into three classes based on their sulfate content. Kappa-carrageenan has one sulfate group per disaccharide, iota-carrageenan has two, and lambda-carrageenan has three. A common seaweed used for manufacturing the

hydrophilic A hydrophile is a molecule or other molecular entity that is attracted to water molecules and tends to be dissolved by water.Liddell, H.G. & Scott, R. (1940). ''A Greek-English Lexicon'' Oxford: Clarendon Press. In contrast, hydrophobes are n ...

colloids A colloid is a mixture in which one substance consisting of microscopically dispersed insoluble particles is suspended throughout another substance. Some definitions specify that the particles must be dispersed in a liquid, while others exten ...

to produce carrageenan is ''

Chondrus crispus ''Chondrus crispus''—commonly called Irish moss or carrageenan moss (Irish ''carraigín'', "little rock")—is a species of red algae which grows abundantly along the rocky parts of the Atlantic coasts of Europe and North America. In its fresh ...

'' (Irish moss), which is a dark red, parsley-like alga that grows attached to rocks. Gelatinous extracts of ''C. crispus'' have been used as food additives since approximately the fifteenth century. Carrageenan is a

vegetarian Vegetarianism is the practice of abstaining from the Eating, consumption of meat (red meat, poultry, seafood, insects as food, insects, and the flesh of any other animal). It may also include abstaining from eating all by-products of animal slau ...

and

vegan Veganism is the practice of abstaining from the use of animal products and the consumption of animal source foods, and an associated philosophy that rejects the commodity status of animals. A person who practices veganism is known as a ve ...

alternative to

gelatin Gelatin or gelatine () is a translucent, colorless, flavorless food ingredient, commonly derived from collagen taken from animal body parts. It is brittle when dry and rubbery when moist. It may also be referred to as hydrolyzed collagen, coll ...

in some applications, and is used to replace gelatin in confectionery and other food. The first industrial commercial cultivation of ''

Eucheuma ''Eucheuma'', commonly known as sea moss or gusô (), is a rhodophyte seaweed that may vary in color (purple, brown, and green). ''Eucheuma'' species are used in the production of carrageenan, an ingredient for cosmetics, food processing, and ind ...

'' and ''

Kappaphycus ''Kappaphycus'' is a genus of red algae. Species are distributed in the waters of East Africa, Indonesia, Malaysia, Hainan Island, the Philippines, and Micronesia.Guiry, M. D. In: Guiry, M. D. & G. M. Guiry. 2013''Kappaphycus''.AlgaeBase. Nationa ...

'' spp. for carrageenan was developed in the

Philippines The Philippines, officially the Republic of the Philippines, is an Archipelagic state, archipelagic country in Southeast Asia. Located in the western Pacific Ocean, it consists of List of islands of the Philippines, 7,641 islands, with a tot ...

. The global top producers of carrageenan are the Philippines and

Indonesia Indonesia, officially the Republic of Indonesia, is a country in Southeast Asia and Oceania, between the Indian Ocean, Indian and Pacific Ocean, Pacific oceans. Comprising over List of islands of Indonesia, 17,000 islands, including Sumatra, ...

. Carrageenan, along with

agar Agar ( or ), or agar-agar, is a jelly-like substance consisting of polysaccharides obtained from the cell walls of some species of red algae, primarily from " ogonori" and " tengusa". As found in nature, agar is a mixture of two components, t ...

, is used to produce traditional jelly desserts in the

called ''

gulaman ''Gulaman'', in Filipino cuisine, is a bar, or powdered form, of dried agar or carrageenan extracted from edible seaweed used to make jelly-like desserts. In common usage, it also usually refers to the refreshment '' sago't gulaman'', somet ...

''. No clinical evidence establishes carrageenan as an unsafe food ingredient, mainly because its fate after digestion is inadequately determined.

Properties

Moleculare structure of different carrageenan types

Carrageenans are large, highly flexible molecules that form curling helical structures. This gives them the ability to form a variety of different gels at room temperature. They are widely used in the food and other industries as

thickening A thickening agent or thickener is a substance which can increase the viscosity of a liquid without substantially changing its other properties. Edible thickeners are commonly used to thicken sauces, soups, and puddings without altering their ...

and stabilizing agents. All carrageenans are high-molecular-weight polysaccharides and mainly made up of alternating 3-linked β-D-galactopyranose (G-units) and 4-linked α-D-galactopyranose (D-units) or 4-linked 3,6-anhydro-α-D-galactopyranose (DA-units), forming the disaccharide repeating unit of carrageenans. There are three main commercial classes of carrageenan: * ''Kappa'' forms strong, rigid gels in the presence of potassium ions, and reacts with dairy proteins. It is sourced mainly from ''

Kappaphycus alvarezii ''Kappaphycus alvarezii'', the elkhorn sea moss, is a species of red algae. The elkhorn sea moss varies in size, weight, and age. It is a dark greenish-brown hue and can sometimes be deep purple. The moss is cylindrical in shape throughout the s ...

''. * ''Iota'' forms soft gels in the presence of calcium ions. It is produced mainly from ''

Eucheuma denticulatum ''Eucheuma denticulatum'' is a species of red algae and one of the primary sources of iota carrageenan. It exists naturally in the Philippines, tropical Asia, and the western Pacific, but for the commercial extraction of carrageenan it is usuall ...

''. * ''Lambda'' does not gel, and is used to thicken dairy products. The primary differences that influence the properties of kappa, iota, and lambda carrageenan are the number and position of the ester sulfate groups on the repeating

galactose Galactose (, ''wikt:galacto-, galacto-'' + ''wikt:-ose#Suffix 2, -ose'', ), sometimes abbreviated Gal, is a monosaccharide sugar that is about as sweetness, sweet as glucose, and about 65% as sweet as sucrose. It is an aldohexose and a C-4 epime ...

units. Higher levels of ester sulfate lower the solubility temperature of the carrageenan and produce lower strength gels, or contribute to gel inhibition (lambda carrageenan). Many red algal species produce different types of carrageenans during their developmental history. For instance, the genus '' Gigartina'' produces mainly kappa carrageenans during its

gametophytic A gametophyte () is one of the two alternating multicellular phases in the life cycles of plants and algae. It is a haploid multicellular organism that develops from a haploid spore that has one set of chromosomes. The gametophyte is the sex ...

stage, and lambda carrageenans during its sporophytic stage. All are soluble in hot water, but in cold water, only the lambda form (and the sodium salts of the other two) are soluble. When used in food products, carrageenan has the EU additive

E number E numbers, short for Europe numbers, are codes for substances used as food additives, including those found naturally in many foods, such as vitamin C, for use within the European Union (EU) and European Free Trade Association (EFTA). Commonly ...

s E407 or E407a when present as "processed eucheuma seaweed". Technically carrageenan is considered a dietary fibre.http://www.marine-science.co.jp/english/goods/carra.html , Marine Science Co. Ltd. In parts of Scotland and Ireland, where it is known by a variety of local and native names, ''

'' is boiled in milk and strained, before sugar and other flavourings such as vanilla, cinnamon, brandy, or whisky are added. The end-product is a kind of jelly similar to

panna cotta Panna cotta (; ; ) is an Italian dessert of sweetened cream thickened with gelatin and molded. The cream may be aromatized with coffee, vanilla, or other flavorings. History The name ''panna cotta'' is not mentioned in Italian cookbooks before ...

tapioca Tapioca (; ) is a starch extracted from the tubers of the cassava plant (''Manihot esculenta,'' also known as manioc), a species native to the North Region, Brazil, North and Northeast Region, Brazil, Northeast regions of Brazil, but which has ...

, or

blancmange Blancmange (, from , ) is a sweet dessert popular throughout Europe commonly made with milk or cream, and sugar, thickened with rice flour, gelatin, corn starch, or Chondrus crispus, Irish moss (a source of carrageenan), and often flavoured wit ...

Production

Although carrageenans were introduced on an industrial scale in the 1930s, they were known to be used in

China China, officially the People's Republic of China (PRC), is a country in East Asia. With population of China, a population exceeding 1.4 billion, it is the list of countries by population (United Nations), second-most populous country after ...

since around 600 BC (where ''Gigartina'' was used) and in

Ireland Ireland (, ; ; Ulster Scots dialect, Ulster-Scots: ) is an island in the North Atlantic Ocean, in Northwestern Europe. Geopolitically, the island is divided between the Republic of Ireland (officially Names of the Irish state, named Irelan ...

around 400 AD. Carrageenan derived from ''

'' spp. (today one of the main cultivated sources of carrageenan), known as ''

gusô ''Eucheuma'', commonly known as sea moss or gusô (), is a rhodophyte seaweed that may vary in color (purple, brown, and green). ''Eucheuma'' species are used in the production of carrageenan, an ingredient for cosmetics, food processing, and ind ...

'' or ''tambalang'' in the

Visayan languages The Bisayan languages or Visayan languages are a subgroup of the Austronesian languages spoken in the Philippines. They are most closely related to Tagalog and the Bikol languages, all of which are part of the Central Philippine languages. Mo ...

, has also been traditionally used as food in the

. They were first recorded in the ''Diccionario De La Lengua Bisaya, Hiligueina y Haraia de la isla de Panay y Sugbu y para las demas islas'' (c.1637) of the Augustinian missionary Alonso de Méntrida . In the book, Méntrida describes gusô as being cooked until it melts, and then allowed to congeal into a sour dish. The most commonly used sources are ''Eucheuma cottonii'', ''Kappaphycus alvarezii'', and ''Eucheuma spinosum'', which together provide about three-quarters of the world production. These grow from the sea surface to a depth of about . The seaweed is normally grown on nylon lines strung between bamboo floats, and it is harvested after three months or so, when each plant weighs approximately . After harvest, the seaweed is dried, baled, and sent to the carrageenan manufacturer. There the seaweed is ground, sifted to remove impurities such as

sand Sand is a granular material composed of finely divided mineral particles. Sand has various compositions but is usually defined by its grain size. Sand grains are smaller than gravel and coarser than silt. Sand can also refer to a textural ...

, and washed thoroughly. After treatment with hot

alkali In chemistry, an alkali (; from the Arabic word , ) is a basic salt of an alkali metal or an alkaline earth metal. An alkali can also be defined as a base that dissolves in water. A solution of a soluble base has a pH greater than 7.0. The a ...

solution (e.g., 5–8%

potassium hydroxide Potassium hydroxide is an inorganic compound with the formula K OH, and is commonly called caustic potash. Along with sodium hydroxide (NaOH), KOH is a prototypical strong base. It has many industrial and niche applications, most of which utili ...

), the

cellulose Cellulose is an organic compound with the chemical formula, formula , a polysaccharide consisting of a linear chain of several hundred to many thousands of glycosidic bond, β(1→4) linked glucose, D-glucose units. Cellulose is an important s ...

is removed from the carrageenan by

centrifugation Centrifugation is a mechanical process which involves the use of the centrifugal force to separate particles from a solution according to their size, shape, density, medium viscosity and rotor speed. The denser components of the mixture migrate ...

and

filtration Filtration is a physical separation process that separates solid matter and fluid from a mixture using a ''filter medium'' that has a complex structure through which only the fluid can pass. Solid particles that cannot pass through the filte ...

. The resulting carrageenan solution is then concentrated by

evaporation Evaporation is a type of vaporization that occurs on the Interface (chemistry), surface of a liquid as it changes into the gas phase. A high concentration of the evaporating substance in the surrounding gas significantly slows down evapora ...

. It is dried and ground to specification. There are three types of industrial processing:

Semi-refined

This is only produced from ''E. cottonii'' or ''E. spinosum''. The raw weed is first sorted and crude contaminants are removed by hand. The weed is then washed to remove salt and sand, and then cooked in hot alkali to increase the gel strength. The cooked weed is washed, dried, and milled. ''E. spinosum'' undergoes a much milder cooking cycle, as it dissolves quite readily. The product is called semi-refined carrageenan, Philippines natural grade, or, in the U.S., it simply falls under the common carrageenan specification. cleaned and washed seaweed ↓ extraction ↓ coarse filtration → seaweed residue ↓ fine filtration → used filter aids ↓ ↓-------------- concentration --------------↓ preparation with KCl preparation with alcohol ↓ ↓ gel pressing alcohol recovery ↓ ↓ drying drying ↓ ↓ milling milling ↓ ↓ blending blending ↓ ↓ gel refined carrageenan refined carrageenan

Refined

The essential difference in the refining process is that the carrageenan is first dissolved and filtered to remove cell wall debris. The carrageenan is then precipitated from the clear solution, either by isopropyl alcohol (propan-2-ol) or by potassium chloride.

Mixed processing

A hybrid technology in which seaweed is treated heterogeneously as in the semirefined process exists, but alcohol or high salt levels are used to inhibit dissolution. This process is often used on South American seaweeds and gives some of the cost benefits of semirefined processing, while allowing a wider range of seaweeds to be processed, however, the naturally low cellulose levels in some South American seaweeds allow them to be heterogeneously processed and still be sold under the EU refined specification.

Grades

There are two basic grades of carrageenan, refined (RC) and semi-refined (SRC). The latter is also known as "processed ''Eucheuma'' seaweed" (PES) and "Philippine natural grade" (PNG) carrageenan. In the European Union, refined carrageenan is designated by the

E-407 and semi-refined carrageenan as E-407a. Refined carrageenan has a 2% maximum for acid-insoluble material and is produced by alcohol precipitation or potassium chloride gel press process. Semi-refined carrageenan has a much higher cellulose content and is produced in a less complex process. Indonesia, the Philippines, and Chile are three main sources of raw material and extracted carrageenan.

Uses and applications

Food and other domestic uses

Dessert Dessert is a course (food), course that concludes a meal; the course consists of sweet foods, such as cake, biscuit, ice cream, and possibly a beverage, such as dessert wine or liqueur. Some cultures sweeten foods that are more commonly umami, ...

ice cream Ice cream is a frozen dessert typically made from milk or cream that has been flavoured with a sweetener, either sugar or an alternative, and a spice, such as Chocolate, cocoa or vanilla, or with fruit, such as strawberries or peaches. Food ...

, cream, milkshakes, yogurts, salad dressings, sweetened

condensed milk Condensed milk is Milk#Cow, cow's milk from which water has been removed (roughly 60% of it). It is most often found with sugar added, in the form of sweetened condensed milk, to the extent that the terms "condensed milk" and "sweetened condensed m ...

s *

Sauce In cooking, a sauce is a liquid, cream, or semi- solid food, served on or used in preparing other foods. Most sauces are not normally consumed by themselves; they add flavour, texture, and visual appeal to a dish. ''Sauce'' is a French wor ...

s: to increase viscosity *

Beer Beer is an alcoholic beverage produced by the brewing and fermentation of starches from cereal grain—most commonly malted barley, although wheat, maize (corn), rice, and oats are also used. The grain is mashed to convert starch in the ...

: clarifier to remove haze-causing proteins *

Pâté Pâté ( , , ) is a forcemeat. Originally, the dish was cooked in a pastry case; in more recent times it is more usually cooked without pastry in a terrine. Various ingredients are used, which may include meat from pork, poultry, fish or bee ...

s and processed

meat Meat is animal Tissue (biology), tissue, often muscle, that is eaten as food. Humans have hunted and farmed other animals for meat since prehistory. The Neolithic Revolution allowed the domestication of vertebrates, including chickens, sheep, ...

s (e.g., ham): substitute for fat, increase water retention, increase volume, or improve slicing *

Soy milk Soy milk (or soymilk), also known as soya milk, is a plant-based milk produced by soaking and grinding soybeans, boiling the mixture, and filtering out remaining particulates. It is a stable emulsion of oil, water, and protein. Its original ...

and other

plant milk Plant milk is a category of non-dairy beverages made from a water-based plant extract for flavoring and aroma. Nut milk is a subcategory made from nuts, while other plant milks may be created from grains, pseudocereals, legumes, seeds or endosp ...

s: to thicken * Diet sodas: to enhance texture and suspend flavours *

Pet food Pet food is animal feed intended for consumption by pets. Typically sold in pet stores and supermarkets, it is usually specific to the type of animal, such as dog food or cat food. Most meat used for animals is a byproduct of the human food indus ...

Toothpaste Toothpaste is a paste or gel dentifrice that is used with a toothbrush to clean and maintain the aesthetics of Human tooth, teeth. Toothpaste is used to promote oral hygiene: it is an abrasive that aids in removing dental plaque and food from th ...

: stabilizer to prevent constituents separating *

Vegetarian hot dog A vegetarian hot dog is a hot dog produced completely from non-meat products. Unlike traditional home-made meat sausages, the casing is not made of intestine, but of cellulose or other plant-based ingredients. The filling is usually based on some ...

s *

Shampoo Shampoo () is a hair care product, typically in the form of a viscous liquid, that is formulated to be used for cleaning (scalp) hair. Less commonly, it is available in solid bar format. (" Dry shampoo" is a separate product.) Shampoo is use ...

and cosmetic creams: thickener *

Personal lubricant Personal lubricants (colloquially termed lube) are specialized lubricants used during sexual acts, such as intercourse and masturbation, to reduce friction to or between the penis and vagina, anus or other body parts, or applied to sex toys to ...

s * Air freshener gels * Fire fighting foam: thickener to cause foam to become sticky * Marbling: the ancient art of paper and fabric marbling uses a carrageenan mixture on which to float paints or inks; the paper or fabric is then laid on it, absorbing the colours * Shoe polish: to increase

viscosity Viscosity is a measure of a fluid's rate-dependent drag (physics), resistance to a change in shape or to movement of its neighboring portions relative to one another. For liquids, it corresponds to the informal concept of ''thickness''; for e ...

Biotechnology Biotechnology is a multidisciplinary field that involves the integration of natural sciences and Engineering Science, engineering sciences in order to achieve the application of organisms and parts thereof for products and services. Specialists ...

: to immobilize cells and enzymes * Pharmaceuticals: used as an inactive

excipient An excipient is a substance formulated alongside the active ingredient of a medication. They may be used to enhance the active ingredient’s therapeutic properties; to facilitate drug absorption; to reduce viscosity; to enhance solubility; to i ...

in pills and tablets

Regulatory status

In the U.S., carrageenan is allowed under FDA regulations as a direct food additive and is generally regarded as safe when used as an emulsifier, stabilizer, or thickener in foods, except those standardized foods that do not provide for such use. FDA reviewed carrageenan safety for infant formula. The

European Food Safety Authority The European Food Safety Authority (EFSA) is the agency of the European Union (EU) that provides independent scientific advice and communicates on existing and emerging risks associated with the food chain. EFSA was established in February 2002 ...

concluded "there is no evidence of any adverse effects in humans from exposure to food-grade carrageenan, or that exposure to degraded carrageenan from use of food-grade carrageenan is occurring". The

Joint FAO/WHO expert committee on food additives The Joint FAO/WHO Expert Committee on Food Additives (JECFA) is an international scientific expert committee that is administered jointly by the Food and Agriculture Organization of the United Nations (FAO) and the World Health Organization (WHO). ...

stated in a July 2014 review "that the use of carrageenan in infant formula or formula for special medical purposes at concentrations up to 1000 mg/L is not of concern". Although the US

National Organic Program The National Organic Program (NOP) is the federal regulatory framework in the United States, United States of America governing organic food. It is also the name of the United States Department of Agriculture (USDA) Agricultural Marketing Service ...

(NOP) added carrageenan to its National List of additives allowed to be included in organic foods in 2003, and reauthorized it in 2008, noting it as "critical to organic production and handling operations", on November 18, 2016, the NOP's

National Organic Standards Board The National Organic Standards Board (NOSB) is an advisory board that makes recommendations to the United States Secretary of Agriculture on organic food and products. Members are appointed by the Secretary and these make recommendations, one of the ...

(NOSB) voted to recommend carrageenan be removed from the National List. On April 4, 2018, the

Agricultural Marketing Service The Agricultural Marketing Service (AMS) is an agency of the United States Department of Agriculture; it maintains programs in five commodity areas: cotton and tobacco; dairy; fruit and vegetable; livestock and seed; and poultry. These programs ...

(AMS) (

USDA The United States Department of Agriculture (USDA) is an United States federal executive departments, executive department of the Federal government of the United States, United States federal government that aims to meet the needs of commerc ...

) announced the renewal of carrageenan on the National List, allowing its continued use in food products. The document states,

The NOSB recommended removing carrageenan because they determined that alternative materials, such as gellan gum, guar gum, or xanthan gum, are available for use in organic products ... AMS found sufficient evidence in public comments to the NOSB that carrageenan continues to be necessary for handling agricultural products because of the unavailability of wholly natural substitutes (§ 6517(c)(1)(ii)). Carrageenan has specific uses in an array of agricultural products, and public comments reported that potential substitutes do not adequately replicate the functions of carrageenan across the broad scope of use. Therefore, carrageenan continues to meet the OFPA criteria for inclusion on the National List.

The use of carrageenan in infant formula is prohibited in the EU for precautionary reasons, but is permitted in other food items. In 2018, the

(EFSA) reported that safety of carrageenan in food products is based 75 mg/kg body weight per day. In the UK, the

Food Standards Agency The Food Standards Agency is a non-ministerial government department of the Government of the United Kingdom. It is responsible for protecting public health in relation to food in England, Wales and Northern Ireland. It is led by a board appoin ...

issued a product recall for sweets containing carrageenan, stating that carrageenan "is not permitted as an ingredient in jelly confectionery products as it presents a choking hazard". In a 2015 review, the Joint Expert Committee of the

Food and Agriculture Organization The Food and Agriculture Organization of the United Nations; . (FAO) is a specialized agency of the United Nations that leads international efforts to defeat hunger and improve nutrition and food security. Its Latin motto, , translates ...

of the

United Nations The United Nations (UN) is the Earth, global intergovernmental organization established by the signing of the Charter of the United Nations, UN Charter on 26 June 1945 with the stated purpose of maintaining international peace and internationa ...

and

World Health Organization The World Health Organization (WHO) is a list of specialized agencies of the United Nations, specialized agency of the United Nations which coordinates responses to international public health issues and emergencies. It is headquartered in Gen ...

on Food Additives reported on the use of carrageenan in

infant formula Infant formula, also called baby formula, simply formula (American English), formula milk, baby milk, or infant milk (British English), is a manufactured food designed and marketed for feeding to babies and infants under 12 months of age, ...

stating that the additive was "not of concern" as food for special medical purposes at concentrations up to 1000

milligram The kilogram (also spelled kilogramme) is the base unit of mass in the International System of Units (SI), equal to one thousand grams. It has the unit symbol kg. The word "kilogram" is formed from the combination of the metric prefix kilo- (m ...

s per

litre The litre ( Commonwealth spelling) or liter ( American spelling) (SI symbols L and l, other symbol used: ℓ) is a metric unit of volume. It is equal to 1 cubic decimetre (dm3), 1000 cubic centimetres (cm3) or 0.001 cubic metres (m3). A ...

Toxicity research

In 2018, carrageenan was deemed non-toxic by the

EFSA The European Food Safety Authority (EFSA) is the agency of the European Union (EU) that provides independent scientific advice and communicates on existing and emerging risks associated with the food chain. EFSA was established in February 2002 ...

under certain consumption levels (75 mg/kg of body weight per day), although further research was recommended, mainly focused on the fate of carrageenan during and after digestion, and on any subsequent metabolites. Research has been done into the role of carrageenan in various forms of

inflammatory bowel disease Inflammatory bowel disease (IBD) is a group of inflammatory conditions of the colon and small intestine, with Crohn's disease and ulcerative colitis (UC) being the principal types. Crohn's disease affects the small intestine and large intestine ...

and

allergic reactions Allergies, also known as allergic diseases, are various conditions caused by hypersensitivity of the immune system to typically harmless substances in the environment. These diseases include hay fever, food allergies, atopic dermatitis, alle ...

, with much of the concern centered around the specific α-D-Gal-(1→3)-D-Gal

glycosidic bond A glycosidic bond or glycosidic linkage is a type of ether bond that joins a carbohydrate (sugar) molecule to another group, which may or may not be another carbohydrate. A glycosidic bond is formed between the hemiacetal or hemiketal group o ...

present in carrageenan, which interacts as an

epitope An epitope, also known as antigenic determinant, is the part of an antigen that is recognized by the immune system, specifically by antibodies, B cells, or T cells. The part of an antibody that binds to the epitope is called a paratope. Although e ...

with

TLR4 Toll-like receptor 4 (TLR4), also designated as CD284 (cluster of differentiation 284), is a key activator of the innate immune response and plays a central role in the fight against bacterial infections. TLR4 is a transmembrane protein of approx ...

in cultivated human epithelial cells of the mucous membrane; this is linked to

alpha-gal syndrome Alpha-gal syndrome (AGS), also known as alpha-gal allergy or mammalian meat allergy (MMA), is a type of acquired allergy characterized by a delayed onset of symptoms (3–8 hours) after ingesting mammalian meat. The condition results from past exp ...

. Other mechanisms of carrageenan-induced inflammation have also been proposed.