Cochineal

Etymology

Cochineal is derived from the French "cochenille", derived from Spanish "cochinilla", in turn derived from Latin "coccinus" meaning "scarlet-colored", or from the Latin "coccum", meaning "berry yielding scarlet dye". See also the related word kermes, which is the source of a similar but weaker Mediterranean dye also called crimson, which was used to color cloth red before discovery of cochineal in the New World. Some sources identify the Spanish source word for cochineal as cochinilla "wood louse" (a diminutive form of Spanish cochino, cognate with French cochon, meaning "pig")."

History

Cochineal dye was used by the Aztec and Maya peoples of North and Central America as early as the second century BC. Eleven cities conquered by Montezuma in the 15th century paid a yearly tribute of 2000 decorated cotton blankets and 40 bags of cochineal dye each. Production of cochineal is depicted in Codex Osuna. During the colonial period, the production of cochineal (grana fina) grew rapidly. Produced almost exclusively in Oaxaca by indigenous producers, cochineal became Mexico's second-most valued export after silver. Soon after the Spanish conquest of the Aztec Empire, it began to be exported to Spain, and by the 17th century was a commodity traded as far away as India. The dyestuff was consumed throughout Europe and was so highly prized, its price was regularly quoted on the London and Amsterdam Commodity Exchanges (with the latter one beginning to record it in 1589). In 1777, French botanist Nicolas-Joseph Thiéry de Menonville, presenting himself as a botanizing physician, smuggled the insects and pads of the Opuntia cactus to Saint Domingue. This particular collection failed to thrive and ultimately died out, leaving the Mexican monopoly intact. After the Mexican War of Independence in 1810–1821, the Mexican monopoly on cochineal came to an end. Large-scale production of cochineal emerged, especially in Guatemala and the Canary Islands; it was also cultivated in Spain and North Africa.

Spain's conquest of a New World empire in the 16th century introduced new pigments and colors to peoples on both sides of the Atlantic. Carmine—a dye and pigment derived from a parasitic insect found in Central and South America—attained great status and value in Europe. Produced from harvested, dried, and crushed cochineal insects, carmine could be—and still is—used in fabric dye, food dye, body paint, or—in its solid lake form—almost any kind of paint or cosmetic.

The Florentine Codex contains a variety of illustrations with multiple variations of the red pigments. Specifically in the case of achiotl (light red), technical analysis of the paint reveals multiple layers of the pigment although the layers of the pigment is not visible to the naked eye. Therefore, it proves that the process of applying multiple layers is more significant in comparison to the actual color itself. Furthermore, the process of layering the various hues of the same pigment on top of each other enabled the Aztec artists to create variations in the intensity of the subject matter. A bolder application of pigment draws the viewer's eye to the subject matter which commands attention and suggests a power of the viewer. A weaker application of pigment commands less attention and has less power. This would suggest that the Aztec associated the intensity of pigments with the idea of power and life.

Natives of Peru had been producing cochineal dyes for textiles since at least 700 CE, but Europeans had never seen the color before. When the Spanish invaded the Aztec empire in what is now Mexico, they were quick to exploit the color for new trade opportunities. Carmine became the region's second-most-valuable export next to silver. Pigments produced from the cochineal insect gave the Catholic cardinals their vibrant robes and the English "Redcoats" their distinctive uniforms. The true source of the pigment—an insect—was kept secret until the 18th century, when biologists discovered the source.

The demand for cochineal fell sharply with the appearance on the market of alizarin crimson and many other artificial dyes discovered in Europe in the middle of the 19th century, causing a significant financial shock in Spain as a major industry almost ceased to exist. The delicate manual labour required for the breeding of the insect could not compete with the modern methods of the new industry, and even less so with the lowering of production costs. The "tuna blood" dye (from the Mexican name for the Opuntia fruit) stopped being used and trade in cochineal almost totally disappeared in the course of the 20th century. In recent decades, the breeding of cochineal has been done mainly for the purposes of maintaining the tradition rather than to satisfy any sort of demand. However, the product has become commercially valuable again. One reason for its popularity is that many commercial synthetic red dyes and food colorings have been found to be carcinogenic.

Art

The carmine of antiquity also contains carminic acid, and was extracted from a similar insect, Kermes vermilio, which lives on Quercus coccifera oaks native to the Near East, and the European side of the Mediterranean Basin. Kermes carmine was used as a dye and a laked pigment in ancient Egypt, Greece, Armenia and the Near East and is one of the oldest organic pigments. Recipes for artists' use of carmine appear in many early painting and alchemical handbooks throughout the Middle Ages; the laking process for both pigments was improved in the 19th century. Carmine was not light-fast and was largely abandoned in art.

Spanish influence changed the way in which Aztecs used pigments, particularly in their manuscripts. For example, cochineal was replaced by Spanish dyes like minium and alizarin crimson. The image of Moctezuma's death (seen to the right) uses both indigenous and Spanish pigments, and is therefore representative of the transition and influence between cultures.

Biology

Cochineal insects are soft-bodied, flat, oval-shaped scale insects. The females, wingless and about 5 mm (0.20 in) long, cluster on cactus pads. They penetrate the cactus with their beak-like mouthparts and feed on its juices, remaining immobile unless alarmed. After mating, the fertilised female increases in size and gives birth to tiny nymphs. The nymphs secrete a waxy white substance over their bodies for protection from water loss and excessive sun. This substance makes the cochineal insect appear white or grey from the outside, though the body of the insect and its nymphs produces the red pigment, which makes the insides of the insect look dark purple. Adult males can be distinguished from females in that males have wings, and are much smaller.

The cochineal disperses in the first nymph stage, called the "crawler" stage. The juveniles move to a feeding spot and produce long wax filaments. Later, they move to the edge of the cactus pad, where the wind catches the wax filaments and carries the insects to a new host. These individuals establish feeding sites on the new host and produce a new generation of cochineals. Male nymphs feed on the cactus until they reach sexual maturity. At this time, they can no longer feed at all and live only long enough to fertilise the eggs. They are, therefore, seldom observed. In addition, females typically outnumber males due to environmental factors.

Host cacti

Dactylopius coccus is native to tropical and subtropical South America and North America in Mexico, where their host cacti grow natively. They have been widely introduced to many regions where their host cacti also grow. About 200 species of Opuntia cacti are known, and while it is possible to cultivate cochineal on almost all of them, the most common is Opuntia ficus-indica. D. coccus has only been noted on Opuntia species, including O. amyclaea, O. atropes, O. cantabrigiensis, O. brasilienis, O. ficus-indica, O. fuliginosa, O. jaliscana, O. leucotricha, O. lindheimeri, O. microdasys, O. megacantha, O. pilifera, O. robusta, O. sarca, O. schikendantzii, O. stricta, O. streptacantha, and O. tomentosa. Feeding cochineals can damage and kill the plant. Other cochineal species feed on many of the same Opuntia, and the wide range of hosts reported for D. coccus likely is because of the difficulty in distinguishing it from other Dactylopius species.

Farming

A nopal cactus farm for the production of cochineal is traditionally known as a nopalry. The two methods of farming cochineal are traditional and controlled. Cochineals are farmed in the traditional method by planting infected cactus pads or infesting existing cacti with cochineals and harvesting the insects by hand. The controlled method uses small baskets called Zapotec nests placed on host cacti. The baskets contain clean, fertile females that leave the nests and settle on the cactus to await fertilization by the males. In both cases, the cochineals must be protected from predation, cold, and rain. The complete cycle lasts three months, during which time the cacti are kept at a constant temperature of 27 °C (81 °F). At the end of the cycle, the new cochineals are left to reproduce or are collected and dried for dye production.

To produce dye from cochineals, the insects are collected when they are around 90 days old. Harvesting the insects is labour-intensive, as they must be individually knocked, brushed, or picked from the cacti and placed into bags. The insects are gathered by small groups of collectors who sell them to local processors or exporters.

Several natural enemies can reduce the population of the insects on hosts. Of all the predators, insects seem to be the most important group. Insects and their larvae such as pyralid moths (order Lepidoptera), which destroy the cactus, and predators such as lady bugs (Coleoptera), various Diptera (such as Syrphidae and Chamaemyiidae), lacewings (Neuroptera), and ants (Hymenoptera) have been identified, as well as numerous parasitic wasps. Many birds, human-commensal rodents (especially rats) and reptiles also prey on cochineal insects. In regions dependent on cochineal production, pest control measures are taken seriously. For small-scale cultivation, manual methods of control have proved to be the safest and most effective. For large-scale cultivation, advanced pest control methods have to be developed, including alternative bioinsecticides or traps with pheromones.

Farming in Australia

Opuntia species, known commonly as prickly pears, were first brought to Australia in an attempt to start a cochineal dye industry in 1788. Captain Arthur Phillip collected a number of cochineal-infested plants from Brazil on his way to establish the first European settlement at Botany Bay, part of which is now Sydney, New South Wales. At that time, Spain and Portugal had a worldwide cochineal dye monopoly via their New World colonial sources, and the British desired a source under their own control, as the dye was important to their clothing and garment industries; it was used to colour the British soldiers' red coats, for example. The attempt was a failure in two ways: the Brazilian cochineal insects soon died off, but the cactus thrived, eventually overrunning about 100,000 sq mi (259,000 km²) of eastern Australia. The cacti were eventually brought under control in the 1920s by the deliberate introduction of a South American moth, Cactoblastis cactorum, the larvae of which feed on the cactus.

Farming in Ethiopia

The nopal pear has been traditionally eaten in parts of northern Ethiopia, where it is utilized more than cultivated. Carmine cochineal was introduced into northern Ethiopia early in the 2000s to be cultivated among farming communities. Foodsafe exported 2000 tons of dried carmine cochineal over 3 years.

A conflict of interest among communities led to closure of the cochineal business in Ethiopia, but the insect spread and became a pest. Cochineal infestation continued to expand after the cochineal business had ended. Control measures were unsuccessful and by 2014 about 16,000 hectares (62 sq mi) of cactus land had become infested with cochineal.

Dye

Carminic acid is extracted from the female cochineal insects and is treated to produce carmine, which can yield shades of red such as crimson and scarlet. The body of the insect is 19–22% carminic acid. The insects are processed by immersion in hot water or exposure to sunlight, steam, or the heat of an oven. Each method produces a different colour that results in the varied appearance of commercial cochineal. The insects must be dried to about 30% of their original body weight before they can be stored without decaying. It takes about 80,000 to 100,000 insects to make one kilogram of cochineal dye.

The two principal forms of cochineal dye are cochineal extract, a colouring made from the raw dried and pulverised bodies of insects, and carmine, a more purified colouring made from the cochineal. To prepare carmine, the powdered insect bodies are boiled in ammonia or a sodium carbonate solution, the insoluble matter is removed by filtering, and alum is added to the clear salt solution of carminic acid to precipitate the red aluminium salt. Purity of colour is ensured by the absence of iron. Stannous chloride, citric acid, borax, or gelatin may be added to regulate the formation of the precipitate. For shades of purple, lime is added to the alum.

As of 2005, Peru produced 200 tons of cochineal dye per year and the Canary Islands produced 20 tons per year. Chile and Mexico also export cochineal. In Mexico, production and exportation of the dye has been found to lower poverty and improve female literacy. France is believed to be the world's largest importer, and Japan and Italy also import the insect. Much of these imports are processed and re-exported to other developed economies. As of 2005, the market price of cochineal was between US$50 and 80 per kilogram, while synthetic raw food dyes are available at prices as low as $10–20 per kilogram.

Uses

Traditionally, cochineal was used for colouring fabrics. During the colonial period, with the introduction of sheep to Latin America, the use of cochineal increased, as it provided the most intense colour and it set more firmly on woolen garments than on clothes made of materials of pre-Hispanic origin such as cotton or agave and yucca fibers. In general, cochineal is more successful on protein-based animal fibres (including silk) than plant-based material. Once the European market discovered the qualities of this product, the demand for it increased dramatically. By the beginning of the 17th century, it was traded internationally. Carmine became strong competition for other colourants such as madder root, kermes, Polish cochineal, Armenian cochineal, brazilwood, and Tyrian purple, as they were used for dyeing the clothes of kings, nobles, and the clergy. For the past several centuries, it was the most important insect dye used in the production of hand-woven oriental rugs, almost completely displacing lac. It was also used for painting, handicrafts, and tapestries. Cochineal-coloured wool and cotton are important materials for Mexican folk art and crafts.

Cochineal is used as a fabric and cosmetics dye and as a natural food colouring. It is also used in histology as a preparatory stain for the examination of tissues and carbohydrates. In artists' paints, it has been replaced by synthetic reds and is largely unavailable for purchase due to poor lightfastness. Natural carmine dye used in food and cosmetics can render the product unacceptable to vegetarian or vegan consumers. Many Muslims consider carmine-containing food forbidden (haraam) because the dye is extracted from insects and all insects except the locust are haraam in Islam. Jews also avoid food containing this additive, though it is not treif, and some authorities allow its use because the insect is dried and reduced to powder.

Cochineal is one of the few water-soluble colourants to resist degradation with time. It is one of the most light- and heat-stable and oxidation-resistant of all the natural organic colourants and is even more stable than many synthetic food colours. The water-soluble form is used in alcoholic drinks with calcium carmine; the insoluble form is used in a wide variety of products. Together with ammonium carmine, they can be found in meat, sausages, processed poultry products (meat products cannot be coloured in the United States unless they are labeled as such), surimi, marinades, alcoholic drinks, bakery products and toppings, cookies, desserts, icings, pie fillings, jams, preserves, gelatin desserts, juice beverages, varieties of cheddar cheese and other dairy products, sauces, and sweets.

Carmine is considered safe enough for cosmetic use in the eye area. A significant proportion of the insoluble carmine pigment produced is used in the cosmetics industry for hair- and skin-care products, lipsticks, face powders, rouges, and blushes. A bright red dye and the stain carmine used in microbiology is often made from the carmine extract, too. The pharmaceutical industry uses cochineal to colour pills and ointments.

Risks and labeling

In spite of the widespread use of carmine-based dyes in food and cosmetic products, a small number of people have been found to experience occupational asthma, food allergy and cosmetic allergies (such as allergic rhinitis and cheilitis), IgE-mediated respiratory hypersensitivity, and in rare cases anaphylactic shock. In 2009 the FDA ruled that labels of cosmetics and food that include cochineal extract must include that information on their labels (under the name "cochineal extract" or "carmine"). In 2006 the FDA stated it found no evidence of a "significant hazard" to the general population. In the EU authorities list carmine as additive E 120 in the list of EU-approved food additives. An artificial, non-allergenic cochineal dye is labeled E 124. The directive governing food dyes approves the use of carmine for certain groups of foods only, but is still found in several products particularly alcoholic beverages.