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11.8: Food Additives

Food additives are substances added to food to preserve flavor or enhance its taste and/or appearance. Some additives have been used for centuries; for example, preserving food by pickling (with vinegar), salting, as with bacon, preserving sweets or using sulfur dioxide as with wines. With the advent of processed foods in the second half of the twentieth century, many more additives have been introduced, of both natural and artificial origin.  Please take a look at two of the most common additives, coloring agents and preservatives using the Wikipedia links below.  When you see these items listed in the "ingredients" section of a food label, will you be able to recognize them?  What are they made from?  Are they safe to eat in small amounts?  Are they safe to eat in large amounts?  

Food Colorings

Food coloring, or color additive, is any dye, pigment or substance that imparts color when it is added to food or drink. They come in many forms consisting of liquids, powders, gels, and pastes. Food coloring is used both in commercial food production and in domestic cooking. Food colorants are also used in a variety of non-food applications including cosmetics, pharmaceuticals, home craft projects, and medical devices.

People associate certain colors with certain flavors, and the color of food can influence the perceived flavor in anything from candy to wine. Sometimes the aim is to simulate a color that is perceived by the consumer as natural, such as adding red coloring to glacé cherries (which would otherwise be beige), but sometimes it is for effect, like the green ketchup that Heinz launched in 1999. Color additives are used in foods for many reasons including:

  • To make food more attractive, appealing, appetizing, and informative
  • Offset color loss due to exposure to light, air, temperature extremes, moisture and storage conditions
  • Correct natural variations in color
  • Enhance colors that occur naturally
  • Provide color to colorless and "fun" foods
  • Allow consumers to identify products on sight, like candy flavors or medicine dosages

In the United States, the Pure Food and Drug Act of 1906 reduced the permitted list of synthetic colors from 700 down to seven. The seven dyes initially approved were Ponceau 3R (FD&C Red No. 1), amaranth (FD&C Red No. 2), erythrosine (FD&C Red No. 3), indigotine (FD&C Blue No. 2), Light Green SF (FD&C Green No. 2), Naphthol yellow 1 (FD&C Yellow No. 1), and Orange 1 (FD&C Orange No. 1). Even with updated food laws, adulteration continued for many years and this, together with more recent adverse press comments on food colors and health, has continued to contribute to consumer concern about color addition to foodstuffs.

In the 20th century, the improvement of chemical analysis and the development of trials to identify the toxic features of substances added to foods led to the replacement of the negative lists by lists of substances allowed to be used for the production and the improvement of foods. This principle is called a positive listing, and almost all recent legislations are based on it. Positive listing implies that substances meant for human consumption have been tested for their safety, and that they have to meet specified purity criteria prior to their approval by the corresponding authorities.

Widespread public belief that artificial food coloring cause hyperactivity in children originated with Benjamin Feingold a pediatric allergist from California, who proposed in 1973 that salicylates, artificial colors, and artificial flavors cause hyperactivity in children; however, there is no evidence to support broad claims that food coloring causes food intolerance and ADHD-like behavior in children. It is possible that certain food coloring may act as a trigger in those who are genetically predisposed, but the evidence is weak.

After concerns were expressed that food colorings may cause ADHD-like behavior in children, the collective evidence do not support this assertion. The US FDA and other food safety authorities to regularly review the scientific literature, and led the UK Food Standards Agency (FSA) to commission a study by researchers at Southampton University of the effect of a mixture of six food dyes (Tartrazine, Allura Red, Ponceau 4R, Quinoline Yellow WS, Sunset Yellow and Carmoisine (dubbed the "Southampton 6")) on children in the general population. These colorants are found in beverages.The study found "a possible link between the consumption of these artificial colours and a sodium benzoate preservative and increased hyperactivity" in the children; the advisory committee to the FSA that evaluated the study also determined that because of study limitations, the results could not be extrapolated to the general population, and further testing was recommended". The U.S. FDA did not make changes following the publication of the Southampton study, but following a citizen petition filed by the Center for Science in the Public Interest in 2008, requesting the FDA ban several food additives, the FDA reviewed the available evidence, and still made no changes.

Food Preservatives

A preservative is a substance or a chemical that is added to products such as food, beverages, pharmaceutical drugs, paints, biological samples, cosmetics, wood, and many other products to prevent decomposition by microbial growth or by undesirable chemical changes. In general, preservation is implemented in two modes, chemical and physical. Chemical preservation entails adding chemical compounds to the product. Physical preservation entails processes such as refrigeration or drying. Preservative food additives reduce the risk of foodborne infections, decrease microbial spoilage, and preserve fresh attributes and nutritional quality. Some physical techniques for food preservation include dehydration, UV-C radiation, freeze-drying, and refrigeration. Chemical preservation and physical preservation techniques are sometimes combined.

Antimicrobial preservatives prevent degradation by bacteria. This method is the most traditional and ancient type of preserving—ancient methods such as pickling and adding honey prevent microorganism growth by modifying the pH level. The most commonly used antimicrobial preservative is lactic acid. Common antimicrobial preservatives are presented in the table. Nitrates and nitrites are also antimicrobial. The detailed mechanism of these chemical compounds range from inhibiting growth of the bacteria to the inhibition of specific enzymes.

\(\PageIndex{1}\): Antimicrobial preservatives
Compound Comment
sorbic acid, sodium sorbate and sorbates common for cheese, wine, baked goods
benzoic acid, sodium benzoate and benzoates used in acidic foods such as jams, salad dressing, juices, pickles, carbonated drinks, soy sauce
hydroxybenzoate and derivatives stable at a broad pH range
sulfur dioxide and sulfites common for fruits
nitrite used in meats to prevent botulism toxin
nitrate used in meats
lactic acid -
propionic acid and sodium propionate baked goods

The oxidation process spoils most food, especially those with a high fat content. Fats quickly turn rancid when exposed to oxygen. Antioxidants prevent or inhibit the oxidation process. The most common antioxidant additives are ascorbic acid (vitamin C) and ascorbates. Thus, antioxidants are commonly added to oils, cheese, and chips. Other antioxidants include the phenol derivatives. These agents suppress the formation of hydroperoxides. Other preservatives include ethanol and methylchloroisothiazolinone.

\(\PageIndex{2}\): Antioxidants
Compound Comment
ascorbic acid, sodium ascorbate cheese, chips
butylated hydroxytoluene, butylated hydroxyanisole also used in food packaging
gallic acid and sodium gallate oxygen scavenger
sulfur dioxide and sulfites beverages, wine
tocopherols vitamin E activity

Contributors

  • Wikipedia