Cochineal Insects – Do We Still Use Them?
Cochineal insects are soft-bodied, flat, oval-shaped scale insects. The females are wingless and about 5 mm long and they tend to cluster on cactus pads. They penetrate the cactus with their beak-like mouthparts and feed on its juices, then remaining largely immobile.
After mating, the fertilized female increases in size and gives birth to tiny nymphs. The nymphs secrete a waxy white substance over their bodies for protection from water 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 by their diminutive size and their wings.
It is in the nymph stage (also called the crawler stage) that the cochineal disperses. 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 cochineals 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; when they mature they cannot feed at all and live only long enough to fertilize the eggs. They are therefore seldom observed.
A deep crimson dye is extracted from the female cochineal insects. Cochineal is used to produce scarlet, orange and other red tints. The colouring comes from carminic acid. Cochineal extract’s natural carminic-acid content is usually 19-22%. The insects are killed by immersion in hot water (after which they are dried) or by exposure to sunlight, steam, or the heat of an oven. Each method produces a different colour which results in the varied appearance of commercial cochineal.
The insects must be dried to about 30 percent of their original body weight before they can be stored without decaying. It takes about 155,000 insects to make one kilogram of cochineal.
There are two principal forms of cochineal dye:
Cochineal extract itself is a colouring made from the raw dried and pulverised bodies of these insects. Carmine is 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.
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, agave fibers and yucca fibers.
Once the European market had discovered the qualities of this product, their demand for it increased dramatically. Carmine became strong competition for other colourants such as madder root, kermes, Polish cochineal, brazilwood, and Tyrian purple, as they were used for dyeing the clothes of kings, nobles and the clergy.
Cochineal was also used for painting, handicrafts and tapestries. Cochineal-coloured wool and cotton are still important materials for Mexican folk art and crafts.
Now it is used as a fabric and cosmetics dye and as a natural food colouring, as well as for oil paints, pigments and watercolours.
Cochineal is one of the few water-soluble colourants that resist degradation with time. It is one of the most light- and heat-stable and oxidation-resistant of all the natural colourants and is even more stable than many synthetic food colourings. The water-soluble form is used in alcoholic drinks with calcium carmine; the insoluble form is used in a wider 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. The average human consumes one to two drops of carminic acid each year with food.
Carmine is one of the very few pigments considered safe enough for use in eye cosmetics. 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, is used in microbiology and is often made from the carmine extract too. The pharmaceutical industry uses cochineal to colour pills and ointments.
An unknown but small percentage of people have been found to have allergies to carmine, ranging from mild cases of hives to atrial fibrillation and anaphylactic shock.
Carmine has been found to cause asthma in some people. Cochineal is one of the colours that the Hyperactive Children’s Support Group recommends be eliminated from the diet of hyperactive children. Natural carmine dye used in food and cosmetics can render it unacceptable to vegetarian (or vegan) consumers, and many Muslims and Jews consider carmine-containing food forbidden (haraam and treif) because the dye is extracted from insects. Beetroot Powder is the natural alternative used.
As of 2005, Peru produced 200 tonnes of cochineal dye per year and the Canary Islands produced 20 tonnes per year. Chile and Mexico have also recently begun to export cochineal. France is believed to be the world’s largest importer of cochineal; Japan and Italy also import the insect. Much of these imports are processed and re-exported to other developed economies.
Because of the nature of this product purists pay a premium for it while synthetic raw food dyes are available at prices as low as $10-$20 per kilogram.