ADDITIVES

ADDITIVES. Food additives are regulated substances and therefore defined in law. Unfortunately, definitions vary among jurisdictions. A typical definition of a food additive may be: a substance the use of which in a food causes it to become a part of that food or to alter the characteristics of that food. A list of exceptions (Table 1) often follows because such a definition is vague and can include many substances not normally regarded as additives. Regulations are then required that control which additives can be added to which foods, and at what levels they can be added to those foods in which they are permitted.

In the U.S. Code of Federal Regulations, Title 21—Food and Drugs (21CFR170.3), the following definition appears: "Food additives includes all substances not exempted by section 201(s) of the act, the intended use of which results or may reasonably be expected to result, directly or indirectly, either in their becoming a component of food or otherwise affecting the characteristics of food."

The European Union (1994) defined a food additive as "any substance not normally consumed as a food in itself and not normally used as a characteristic ingredient of food whether or not it has nutritive value, the intentional addition of which to food for a technological purpose in the manufacture, processing, preparation, treatment, packaging, transport or storage of such food results, or may be reasonably expected to result, in it or its by-products becoming directly or indirectly a component of such foods."

The Codex Alimentarius Commission (a joint Food and Agriculture Organization of the United Nations [FAO] and World Health Organization [WHO] organization established to develop uniformity of food standards for international trade) has defined a food additive as "any substance not normally consumed as a food by itself and not normally used as a typical ingredient of the food, whether or not it has nutritive value, the intentional addition of which to food for a technological (including organoleptic) purpose in the manufacture, processing, preparation, treatment, packing, packaging, transport or holding of such food results, or may be reasonably expected to result, (directly or indirectly) in it or its byproducts becoming a component of or otherwise affecting the characteristics of such foods. The term does not include contaminants or substances added to food for maintaining or improving nutritional qualities" (Codex Alimentarius Commission, 1999).

In the Canadian Regulations, Part B, Food, Division 1, General, B.01.001, p. 16, of the Canadian Food and Drugs Act (Amendments 1999), "food additive" is defined as "any substance the use of which results, or may reasonably be expected to result, in it or its by-products becoming a part of or affecting the characteristics of a food, but does not include (a) any nutritive material that is used, recognized, or commonly sold as an article or ingredient of food, (b) vitamins, mineral nutrients and amino acids, other than thosse listed in the tables to Division 16, (c) spices, seasonings, flavouring preparations, essential oils, oleoresins and natural extractives, (d) agricultural chemicals, other than those listed in the tables to Division 16, (e) food packaging materials and components thereof, and (f ) drugs recommended for administration to animals that may be consumed as food."

These definitions differ in their specificity, and exceptions to the definitions vary from country to country and trading bloc to trading bloc. These differences can be a source of confusion in the mind of the public regarding what food additives are, as well as a source of nontariff trade barriers between countries.

In the United States, there are two categories of exemptions to the definition (Food Additives Amendment 1958): prior-sanctioned items and GRAS (generally recognized as safe) items [21CFR170.3 (k, l, n, and o)]. The former category was sanctioned by existing legislation (prior to September 6, 1958) as outlined in the Federal Food, Drug, and Cosmetic Act, the Poultry Products Inspection Act, and the Meat Inspection Act. GRAS substances, so declared based on opinions of experts and an extensive history of use, are listed in forty-two categories and include salt, alcoholic beverages, cheeses, baked goods (mixes, flours, ready-to-bake products), condiments, fats and oils, and so forth. They can very loosely be described as the "ingredients" usually found in recipes. Also exempted are thirty-two categories of GRAS food chemicals, which can broadly be classed as processing aids.

In the Directive of the European Communities the exceptions to the definition are: processing aids (which are further defined); agricultural chemicals used in conformity to European Community rules; flavorings as defined by Council Directive; and substances added to foods as nutrients.

Indirect (Unintentional) and Direct Additives and "Carry-Over"

In addition to the definition of "additive" itself, there are also definitions of direct and indirect (unintentional) additives, and the principle of carry-over. Direct additives are added directly to foods for a specific aesthetic or technological purpose. They are usually declared on labels. Indirect additives become part of the food usually in trace amounts that are harmless to consumers and are present because of packaging, storage, processing, or handling. These are also referred to as unintentional additives. Their presence in foods results from the principle of "carry-over," that is, they are permitted agricultural chemicals used on farm products or accepted drugs and nutrients fed to animals. Such agricultural chemicals, even when used according to good husbandry practices, may end up in the food supply, or additives used as a component in ingredients may turn up in trace amounts in finished food products. Such substances are permitted only if the substance was permitted in the raw material or ingredient initially; the amount in the raw material does not exceed the maximum amount so permitted in the raw material or ingredient; and the amount carried over into the food does not exceed that expected by good manufacturing practice [see, for example, Codex Stan 192-1995 (Rev.2-1999) p. 3, Section 4].

History of Food Additives

Substances have been added to foods to achieve some desirable characteristic in a finished food product for many hundreds, if not thousands, of years. For example, salt has been used to preserve hams as well as some hard sausages and salted cod; to flavor foods; and to control the fermentation of a variety of vegetables such as sauerkraut and sauerrüben (fermented rutabagas), and fish products (for example, rollmops, Bismarck herring, fish sauce, Malaysian nuoc-mam, shrimp paste, belacan, and anchovies). Historically bakers used fats to "shorten," that is, lubricate, dough for certain baking products. In these two examples, salt and certain fats have been used as processing aids.

Spices, herbs, and some vegetables were added to foods to develop unique and pleasing flavors, and in some cases to enhance or preserve foods. For example, Hartley, in Food in England (1985, p. 563), describes claims made by cider processors that straw mats (processing aids) used to separate layers of apples in presses for cider making produced the best cider because of the minerals drawn up by the straw from the soil. There are many kinds of leavening agents used in baking: yeast, sourdough starter cultures, baking soda and an acid (for example, soured milk) for soda breads, or commercially prepared baking powder which contains the previous two agents (plus others) together in one mix. Salts of sulfurous acid (sulfites) are used to control the fermentation of grape musts and were also used by fraudulent butchers to give a fresher, brighter appearance to ground meats.

Prior to the development of food science and before the establishment of a rigorous system of food inspections, food manufacturers and food retailers often took advantage of this lack of good analytical methods for food products by mixing adulterants into foods to deceive the consumers. Elisa Maria Rundell in her book, A New System of Domestic Cookery, describes a procedure (1828, p. 336) to determine whether bread has been adulterated with whiting or chalk, commenting that this type of adulteration was common practice.

A. H. Hassall (1817–1894), an early food analyst, determined (ca.1850) that much of the coffee sold in England had, as "additives," chicory, roasted wheat, burnt sugar for coloring matter, beans, and potato flour. An earlier chemist, Fredrick Accum (1769–1838), started one of the first training centers in practical (analytical) chemistry in England and reported such fraudulent practices as mustard adulterated with radish seed; vinegar sophisticated with sulfuric acid; cream enhanced with rice powder and arrowroot; cayenne pepper adulterated with red lead; and confectionery colored with vermilion (mercuric sulfide) (see also Skuse, c. 1900). The work of Accum, but primarily that of Hassall, led directly to the passing of food legislation preventing the adulteration of foods and drink in the U.K. (Farrer, 1996, 1997).

Traditionally, innocent additives have been added to foods. Cooking skills passed on from mothers to daughters and often to be found in some of today's older cookbooks taught the use of unripe apples (or apple skins) to assist the gelling of fruit jams; lemon juice added for acidification of foods; and Hart's horn (deer antler) shavings used for gelation. Today, the active components of these natural ingredients, pectin in the apples, citric acid in the lemons, and gelatin in the antlers are well-recognized food additives.

In many people's minds, however, food additives are considered to be a suspicious, comparatively modern invention created in large part by food manufacturers to cheapen products and hoodwink the public.

In earlier times, there was some truth to this suspicion. Today, this is far from the truth. There was, and is, an absolute need for improved processing aids to satisfy the demands by consumers for attractive, tasty, safe food products of uniformly high quality as well as for new products.

In the United States, individual states were the first to develop food legislation and a system of food inspection. In terms of federal legislation, the Federal Food and Drugs Act of 1906, popularly known as the Pure Food Law, for prevention of adulteration of foodstuffs, was passed, and came into force on January 1, 1907. It dealt largely with adulteration and misbranding of foods.

The Need for Additives

Using such natural products as apple skins or lemon juice as food processing aids causes problems in large-scale manufacturing situations. First, the desired active ingredients in natural products are not consistent in quality, properties, versatility, or concentration in their natural state. Furthermore, they may bring both undesirable flavor attributes, associated with their source, to the finished product, as well as microbiological contamination. For example, using orange or lemon juice to acidify a food inevitably brings the flavor of oranges or lemons, which may not be desired in the finished product. It would be the rare householder who would want to make her own red color by crushing the dried insect used to make an extract of cochineal for baking or candy making.

Consumers who shop for groceries only once a week or even only once every two weeks still want their food purchases to remain as fresh, wholesome, and safe as the day they were purchased. The consumer's demand for manufactured, prepared foods that have a high uniform quality with good shelf life characteristics and are as close to the natural state as possible has been the major determinant for an increase in the use of additives. Additives preserve color and flavor as well as maintaining safety and nutritive value throughout both processing and the product's shelf life.

The box above lists some quality characteristics consumers prefer that require food additives to be added to foods. For example, in dietetic foods (low-salt, low-fat, low-sugar, or lactose-free foods), there must be some alternative substance (an additive) to replace the taste impact that salt provides, or to provide the mouth feel found in full-fat foods, to replace the sweetness provided by sugar, or to remove (along with the enzyme lactase) the lactose inherent in milk products. Hence there was a need for new additives that were either synthesized de novo, extracted and purified from natural sources (these additives are termed "nature identical"), or modified chemically to provide unique properties not found with nature-identical substances, for example, modified starches. Some of these properties are resistance to heat and acetic acid, constant viscosity in sauces during prolonged heating or without prolonged storage, special textures such as creaminess or pulpy granularity, or pregelatinization for "instant" rices. Thus, along with consumers' desire for a decreased use of additives there is also a need for newer and more effective additives (Smith, 1993).

Classification and Functions of Additives

Additives perform a specific and necessary aesthetic or functional role in foods. If they did not have a purpose, no government would have considered allowing them. Many additives have several different functions depending on the foods they are added to. In addition to their flavoring and nutritive properties, some herbs, spices, vegetables, and vitamins added to foods have other functional properties as processing aids. For example, vitamin C (ascorbic acid) and vitamin E (tocopherols) are both excellent antioxidants and are used to remove oxygen and prevent oxidation, thus extending the shelf life of many food products. Garlic has long been used for its antimicrobial properties. Thyme and oregano contain thymol, which has a wide spectrum of antimicrobial effectiveness (Beuchat and Golden, 1989).

The only practical way to classify additives is by the purpose for which they are added to foods. The table presents one classification of additives with some typical examples within each classification and examples of foods in which they may be found.

Colors. Colors are either water soluble or oil soluble (see Carriers, extractants, and solvents) and are designed for specific application in aqueous or oily foods. There are three categories of colors: natural or nature-identical, synthetic, and inorganic. Natural or nature-identical colors (colors extracted from natural products or synthesized to resemble their natural counterpart) have two disadvantages. They are frequently mixtures and are, in general, not as stable in foods as are the synthetic colorants. Many change color with the acidity or alkalinity of the food they are added to; many are susceptible to breakdown by oxidation and heat. Synthetic colors are preferred colorants in foods, but questions of their safety have arisen in the past and hence there is widely differing acceptance of their use in many foods by different countries. Inorganic colorants are very stable but have a limited use in foods such as sugars, jams, and confectionery.

In most instances, colorants are permitted according to "good manufacturing practices," that is, governments, working closely with food manufacturers and with the advice of experts, have established minimal, acceptable levels of usage in practice.

Enzymes. Enzymes are biological catalysts that can break down specific materials (substrates) into simpler components or cause changes in the substrate's structure. Carbohydrases break down complex sugars (for example, starches, cellulose, lactose, maltose, and so on) into simpler sugars (saccharification). Lipases break down fats into glycerol and fatty acids. Proteases break down proteins into their constituent amino acids. Other enzymes act as preservatives and scavenge oxygen that may be dissolved in plant tissues or in headspaces in packages and remove it.

Many enzymes are derived from natural sources, for example, rennet from stomachs of calves, sheep, and goats; bromelain and papain from pineapples and papaya, respectively; ficin from latex of fig trees; pancreatin from the pancreas of pigs and oxen. However, an evergrowing number of enzymes are derived from microorganisms such as Bacillus subtilis, various species of molds especially Aspergillus varieties, and yeasts.

Carriers, extractants, and solvents. Carriers and extractants are used to extract flavoring compounds from spices and herbs to produce oleoresins; soluble solids from tea leaves; and coffee beans for the preparation of soluble drinks and for the selective extraction of caffeine in decaffeinated coffees; preparing hop extracts for beers; and extraction of cocoa powder. They are also used to extract fats and oils from oil seeds (defatting) and to dissolve oil-soluble dyes and flavorings, thereby serving as carriers to be added to other foods.

Sweeteners. There are two types of sweeteners: caloric sweeteners that provide minimal calories (usually only 1 or 2 calories) based on their sweetening power compared to that of sucrose, the sweetener they are replacing, and noncaloric sweeteners, which provide no calories. In U.S. regulations, caloric sweeteners as defined here are referred to as "non-nutritive sweeteners" and further defined as "substances having less than 2 percent of the caloric value of sucrose per equivalent unit of sweetening capacity."

Preservatives. A wide variety of additives are used for preventing or delaying spoilage and are closely restricted in respect to the foods they can be used with and the levels at which they can be used. Some preservatives, such as acetic acid, wood smoke, ascorbic and erythorbic acids, lecithin (component of egg yolk and soybeans), citric acid, and tartaric acid, are generally permitted according to good manufacturing practice. However, sulfurous acid and its salts (sulfites) can cause serious problems in some asthmatics and regulations permit only low levels to be used. Nitrite and nitrate salts, used in meat curing, have been determined to be potential sources of cancer-causing agents and only minimal levels are permitted to be used.

Bleaching, maturing, and dough conditioning agents. These agents are used for whitening flour and improving (maturing and conditioning) flour's baking characteristics in the many varieties of bakery products.

Anticaking agents. These agents reduce the tendency of granulated products (dry mixes, dried egg powders, salt, and so forth) to stick together and help them keep their free-flowing properties.

Emulsifying, gelling, stabilizing, and thickening agents. Emulsifying agents are used in the formation of stable oil-and-water or oil-and-vinegar mixtures. Gelling, stabilizing, and thickening agents form soft gelled structures, thicken suspensions of particulate foods and prevent their separating, and provide mouth feel as bulking agents in low-calorie foods. They are also used to prevent or slow crystallization (staling) in foods.

Firming agents. These agents prevent or inhibit the softening of processed fruits and vegetables, especially during the process of canning in which they receive a severe heat treatment.

Glazing and polishing agents. These agents put a protective surface or coating or polish on a food, particularly confectionery products but also some vegetables and fruits.

pH-Adjusting, acid-reacting, and water-correcting agents. These agents maintain the acid-alkali balance (that is, pH) of foods at a desired level. Many delicate products such as artichokes must be acidified in order to be thermally processed (canned) with a less severe heat process because the usual high temperatures used for canning vegetables would destroy their shape and texture. Acids are also required to release carbon dioxide from leavening agents.

Sequestering agents. These agents act as sponges to gather or reduce in concentration any trace metal ions (especially copper and iron) that might, for example, promote oxidation or otherwise cause spoilage in foods. They improve the quality, color, and stability of canned products.

Starch-modifying agents. These agents can be used only to modify the properties of starch for its use in mixes, sauces, and custards.

Yeast foods. As their name suggests, these agents are used in fermentations with yeast and serve as a food for the yeast in the preparation of the inoculum. An inoculum is a highly concentrated suspension of yeast (or other microorganisms) to be added to malt mashes for beer-making or to bread doughs for leavening purposes or wherever fermentation is desired.

Miscellaneous additives. Propellant gases for the dispensing of foams or aerosol foods are also additives.

Regulation, Control, and Safety of Food Additives

Countries with well-developed food manufacturing industries have food legislation and associated regulations governing the use of food additives. In trade, where regulations between countries may differ, countries may allow conditional entry (where safety is not a concern) requiring relabeling of an offending product or specify compliance to Codex Alimentarius Commission standards before permitting importation.

The process for revoking approval or modifying the conditions of approval of existing food additives or for approving new ones varies from country to country. As problems of public health significance emerge that are attributable to the use of an additive, that information is assessed by panels of experts in the fields of epidemiology and toxicology. Should questions of safety emerge regarding the use of any prior approved additive, an evaluation must be made of the risk/benefit problems associated with continued use (Institute of Food Technologists, 1978). An excellent example of such a risk/benefit assessment can be found in the continued use of nitrate/nitrite salts in cured meat products. Banning the use of the salts in cured meats would most certainly expose the consuming public to the greater danger of botulism poisoning. The absence of these salts would permit the growth of Cl. botulinum in the cured meat and certainly the associated development of the botulinum toxin. On the other hand, these salts are also able under some circumstances to form nitroso-compounds, which are very active carcinogens.

However, there are general principles to guide the use of food additives and the assessment of new ones. No food additive is permitted for use until its safety has been assessed by expert panels of specialists. It is up to the petitioner for use of an additive to supply toxicological data to the government-appointed panel. Evaluations, based on a generally accepted protocol, must be made of the toxicological effect of the additive (Winter and Francis, 1997). Animal testing is required to determine levels of toxicity which are then used to determine human toxicity levels, but if the additive is substantially the same as the natural prior sanctioned or GRAS product, animal testing may not be required.

Toxicity data that are submitted for evaluation are based on assessment of exposure; such data must also determine the level of exposure. This will be influenced by the level used in foods (which is kept to the minimum level to produce the desired effect) and the level that remains in the food after processing. Other factors affecting the dose level are the age and gender of the consumer eating the food; the physical state of that individual (that is, pregnant, lactating, convalescent, with reduced immune system, with allergies, with special diet requirements, and so on); frequency of eating the food to which the additive is added; and the composition of the rest of the diet, which can have a protective effect on the toxicity.

Prior sanctioned additives are regularly reviewed for safety. Submissions for the approval of new additives may take several years and cost many hundreds of thousands of dollars to the petitioner. Such submissions are not undertaken lightly. The consumer's demand for innovative foods with new properties and enhanced safety will certainly see the food industry develop more and functionally better additives that are safe.

See also Adulteration of Food ; Codex Alimentarius ; Consumer Protests ; Food, Composition of ; Food Safety ; International Agencies ; Toxins, Unnatural, and Food Safety .

BIBLIOGRAPHY

Beuchat, Larry, and David Golden. "Antimicrobials Occurring Naturally in Foods." Food Technology 43(1) (January 1989): 134–142.

Canadian Food and Drugs Act and Regulations with amendments 1999, Part B, Food, Division 1, General, B.01.001, p 16.

(U.S.) Code of Federal Regulations, Title 21—Food and Drugs (Cite 21CFR170.3). Introduction. Food and Drugs. This document may be found at the U.S. Food and Drug Administration's home website http://www.fda.gov/. Section 201 (s) can be found at http://www.fda.gov/opacom/laws/fdcact/fdcact1.htm.

Codex Alimentarius Commission. Preamble to the General Standard for Food Additives, Codex Stan 192-1995 (Rev. 2-1999). This can be found at http://www.codexalimentarius.net/.

European Union. Council Directive 89/107/EEC; amended 10.9.1994. This document can be found at http://europa.eu.int/comm/food/fs/sfp/addit_flavor/additives/index_en.html#1.

Farrer, Keith T. H. "Fredrick Accum (1769–1838)—Consultant and Food Chemist." Food Science and Technology Today 10 (1996): 217–222.

Farrer, Keith T. H. "Dr A H Hassall—and Food Technology." Food Science and Technology Today 11 (1997): 81–87.

The (U.K.) Food Labelling Regulations 1996 (Statutory Instrument 1996 No. 1499; Crown Copyright 1996). The full text of these regulations can be found at http://www.hmso.gov.uk/si/si1996/Uksi_19961499_en_2.htm.

Hartley, Dorothy. Food in England. London: Futura, 1985.

Institute of Food Technologists. "Benefit/Risk: Consideration of Direct Food Additives." A Symposium. Food Technology 32 (8) (August 1978): 54–69. This symposium, held in 1978 and comprising five papers, still provides one of the more thorough and accessible discussions on risk/benefit assessment available.

Rundell, Elisa Maria. A New System of Domestic Cookery. London: John Murray, 1828. A recipe book on cookery and household economics primarily but with interesting insights into food, nutritional knowledge, and home economics.

Skuse, E. Skuse's Complete Confectioner: A Practical Guide, 10th ed. London: W. J. Bush & Co., Ltd., ca. 1900.

Smith, J., ed. Technology of Reduced Additive Foods. London: Blackie Academic & Professional, Chapman & Hall, 1993.

Winter, C. K., and F. J. Francis. "Assessing, Managing, and Communicating Chemical Food Risks." Food Technology 51 (5) (May 1997). A comprehensive exploration of the technical aspects of risk assessment.

Gordon William Fuller

Exceptions Often Declared by Governments to the Definition of a "Food Additive"

Exceptions to Definition of Food Additive

• Flavoring preparations such as spices, natural extractives, oleoresins, essential oils, and seasonings
• Nutrients such as amino acids, vitamins, and mineral supplements, some of which may be regulated as to levels permitted in foods
• Any nutritive substance (that is, food ingredient) sold as an article of food or as an ingredient
• Certain permitted agricultural chemicals (used in growing plants) and drugs (administered to animals)
• Packaging materials and their components

In Skuse's Complete Confectioner (10th ed.), published ca. 1900, the author found it necessary to list poisonous colors that confectioners should avoid. Among those he listed are chrome yellow (lead chromate), sulfate of arsenic, red lead, and copper sulfate. Skuse noted that he "knows sugar boilers who are very partial to use a little chrome yellow for stripes."

Marketing people and retailers often defend adding color and flavor to processed foods. Only safe, attractive, nutritious, and flavorful food can be marketed successfully and therefore only such foods will be purchased by consumers. It is only these foods that are ultimately consumed. Good nutrition can be maintained within the population only if attractive, wholesome foods are presented.

Chicory, considered an adulterant in ground coffee, is also used as a coffee-substitute beverage in its own right and is often added to some coffees to give a richer, stronger, roasted flavor to the final beverage.

Need for Food Additives in Manufacturing

Quality Characteristics in Processed Foods Demanded by Consumers that Require Use of Additives in Manufacturing

• Uniformity of products sold by count, size, shape, volume, or weight
• Desire for fresh, semiprepared foods "as fresh and natural appearing as possible" with a safe, long shelf life
• Replacement of nutrients lost or reduced in processing as well as the addition of other health-giving properties equivalent to the unprocessed product
• Additions of special nutrients or other substances for foods for consumers with special nutritional needs
• Dietetic foods with same eating characteristics (flavor, taste, color, texture, and mouth feel) as the regular product
• Flavor, color, and texture (crispness, eye appeal, or moistness) of unprocessed, natural product
• Unique characteristics such a spreadability at room temperature, adherence, flow properties
• Enhancement of keeping qualities and organoleptic characteristics of processed foods for eating enjoyment

General Principles Guiding the Use of Food Additives

Requirement for Uses of Additive

• The additive must serve a useful purpose in preparing, processing, storage, and handling of the food
• The use of the food additive should not deceive, mislead, or defraud the consumer
• The use of the additive should not pose a health hazard either to the general population or to any special segment within the population

Additives

Nearly all commercial tobacco products contain chemical additives. As long ago as the sixteenth century, Spanish sailors applied licorice water to tobacco as a preservative (Browne, p. 55). Today, both cigarette and smokeless tobacco manufacturers publicly acknowledge the use of hundreds of additives in their products. The modern U.S.-style cigarette contains about 10 percent additives by weight, mostly in the form of sugars, humectants, ammonia compounds, cocoa, and licorice. Smokeless tobacco likewise incorporates moisteners, sweeteners, and flavors such as cherry juice. These additives may affect the flavor of the product, sensory properties such as smoothness and impact, and other important product characteristics. Additives can also be used to enhance or alter nicotine delivery, a practice denied by manufacturers.

Role of Additives in Product Design

The flavor of a tobacco product is primarily determined by the tobacco leaf blend, while additives are used to modify or enhance tobacco flavor characteristics. Menthol is the only commonly recognized tobacco flavor category, although vanilla, cherry, orange, and other product flavors have been introduced commercially. Most additives are used in very small amounts—less than .01 percent of total weight. As a result, although the cumulative effect of additives on tobacco flavor may be significant, it is often difficult or impossible to assess the impact of specific flavorants.

Additives perform a number of roles in addition to altering product flavor. For example, additives may also control cigarette burn rates, properties of tobacco such as moisture and consistency, and delivery of specific smoke constituents. Not surprisingly, the most widely used additives—including sugars, cocoa, and licorice—demonstrate important sensory, physiological , and respiratory effects. Both theobromine, the principal alkaloid of the cocoa bean, and glycyrrhizin, the active component in licorice, act as bronchodilators, relaxing the bronchial muscle and therefore enhancing respiratory inhalation. Likewise, the addition of sugars helps to offset bitterness, improve smoothness, and reduce irritation caused by tobacco smoke. Highly aromatic compounds, such as vanillin, may also be used to alter the aroma of side-stream smoke (the smoke produced from the lit end of the cigarette between puffs).

Some additives demonstrate properties that significantly alter product chemistry. A number of additives in both cigarettes and smokeless tobacco products are used for modification of "smoke pH," which is a measure of its acid/base chemistry. Increased "smoke pH" allows more nicotine to be present in the chemical freebase form, which is more readily available for absorption and use in the body (much as crack cocaine is a more potent freebase form of cocaine). Other additives increase or alter the effects of nicotine, or produce their own effects on the central nervous system and brain. For example, pyridine, a cigarette additive, acts as a depressant in much the same way that nicotine does, although it is less potent.

Manufacturers have used modified forms of tobacco, in combination with other design changes, to reduce the amount of tar produced per cigarette and to cut production costs. Modified tobaccos, such as reconstituted tobacco (combined from stems, leaves, and other tobacco scraps), rely on additives to maintain their physical integrity, to promote consistency, and to control resulting tobacco and smoke chemistry. Additional flavorants or enhancing agents may also be used to counteract the loss of sensory or other subjective response in these reduced delivery products.

Many products today are marketed with the claim "no additives." However, a true evaluation of additives must include not only the flavors applied directly to the tobacco but also other chemicals used during stages throughout the production and manufacturing process. Additives are used as tobacco processing agents, as treatment for cigarette papers or filters, or even applied to product packaging (which then allows transfer to the finished product). The hundreds of pesticides and other chemicals used in the growing or harvesting of tobacco may also be present as residues in manufactured tobacco products.

Physiological and Behavioral Effects

Additives may produce important changes to the effects of tobacco, altering dependence, toxicity, or use behaviors. For example, additives may increase the addictive character of tobacco smoke by altering the effects of nicotine or by exerting other pharmacologic effects on the user. Changes to the physiological properties of nicotine could also radically alter the character of tobacco dependence. Additives that enhance the body's interaction with nicotine or other constituents may increase their addictive or toxicological effects. For example, menthol has been shown to enhance drug absorption and demonstrates effects on metabolism that could alter the pharmacological action of other substances in tobacco smoke. Moreover, industry research has demonstrated a 50 percent increase in the binding of nicotine to brain receptors in the presence of the additive levulinic acid. These and other additives could significantly alter the effects of nicotine and other constituents, again without noticeably changing the amount of nicotine delivered.

Changes in chemical composition of tobacco products could alter the site and rate of uptake of nicotine and other constituents. For example, a greater percentage of nicotine delivered in freebase form may result in increased rates of absorption in the mouth (in the case of smokeless tobacco) as well as faster absorption from the lower respiratory tract to the brain (in the case of cigarettes). These changes could alter the intensity of response and increase dependence. The addition of bronchodilators to cigarettes may have similar effects by allowing deeper inhalation and deposition of smoke constituents in areas of the respiratory tract where they are more likely to be absorbed.

One primary use of additives in cigarettes is to counteract the irritation of tobacco smoke and its active component, nicotine. The perception of smoother smoke may facilitate increased or deeper inhalation of tobacco smoke by removing physical barriers. Similarly, reduced irritation may encourage or support increased frequency of use. Published research suggests that increasing ease of inhalation may be linked to increased rates of initiation among youth. Candy-like flavors, such as cherry, may also be used to target youth.

Health Risks and Regulation

No systematic assessment has been conducted of the hundreds of additives used in tobacco products. However, a number of these additives are known to pose direct health risks. Deer tongue extract, once a widely used tobacco flavorant, was banned in some countries and ultimately phased from use due to its high concentration of coumarin, a known animal carcinogen . The combustion products of cigarette additives may pose additional health risks even though the additive from which they were generated is considered safe. For example, cocoa, although harmless on its own, produces carcinogenic compounds when burned. Another significant health issue is exposure to environmental tobacco smoke (ETS). Research suggests that additives may be used to reduce the visibility, irritation, or odor of ETS, possibly increasing nonsmokers' exposure, without rendering the smoke less harmful.

Tobacco manufacturers emphasize in public statements that the majority of additives have been shown to be safe when eaten in foods. However, compounds are significantly more toxic when inhaled or absorbed directly into the bloodstream rather than ingested. In the digestive system, additives and other complex molecules are broken down by enzymes into simpler chemical structures and/or transformed into other compounds. These processes render most substances less toxic to the body. In contrast, tobacco additives escape the metabolic pathways that would help make them less toxic. Although a number of additives are present in commercial products only in small concentrations, it does not follow that these can be considered harmless. Since people often use tobacco products for decades, their long-term exposure must be taken into account.

Even though the use of additives raises significant concerns regarding increased health risks, the tobacco industry has largely been left to police itself. Many countries regulate tar and nicotine levels of tobacco products and require that this information be reported to the public. In most cases, however, legislative authority does not extend to disclosure of additives. Only a handful of countries (Thailand, Canada, Ireland) have enacted meaningful additive disclosure laws, and in each case the availability of information to the public has been severely limited. Some countries have limited or banned use of particular additives, or specify additives that may be permitted for use. In Canada, the list of permitted additives for use in cigarettes is quite small; as a result, Canadian cigarettes differ significantly from cigarettes sold elsewhere.

Increased Addictiveness: Ammonia and Acetaldehyde

T he use of ammonia in Marlboro cigarettes has been widely publicized. Ammonia compounds, especially ammonium hydroxide and diammonium phosphate (DAP), are used in the ammoniation of reconstituted tobacco. The ammonia compounds are reacted with sugars at a high temperature to produce pyrazines and other flavors through a chemical process known as Maillard browning. These flavors demonstrate unique sensory and pharmacological effects. The ammoniated tobacco produces a characteristic mild smoke, increased "smoke pH," and a more efficient transfer of nicotine, all of which combine to make the cigarette more addictive. Early adoption of DAP in tobacco processing in the 1950s is widely believed to be responsible for the unique flavor of Marlboro cigarettes and, ultimately, their success worldwide.

In the early 1980s, the research scientist Victor DeNoble and coworkers at Philip Morris studied the behavioral effects of nicotine and acetaldehyde (a byproduct of sugar) in rats. The results of this research showed that the two compounds work together to produce greater addictive effects. DeNoble later claimed in public testimony that based on this information, Philip Morris increased the level of acetaldehyde in Marlboro cigarettes by 40 percent between 1982 and 1992 through the addition of sugars (Bates 1999).

In 1994 in the United States, major cigarette manufacturers voluntarily released to the public a list of 599 potential additives for use in their products. A similar list was produced by smokeless tobacco manufacturers. Both lists were composite and did not provide brand-specific information. Some tobacco manufacturer websites provide an updated summary of additives used in their products, including maximum levels, although again this information is composite rather than brand-specific. Overall, the information provided by tobacco manufacturers is not sufficient to provide a reliable assessment of the effects of additives on addiction and toxicity.

See Also Addiction; "Light" and Filtered Cigarettes; Menthol Cigarettes; Nicotine; Processing; Product Design; Regulation of Tobacco Products in the United States; "Safer" Cigarettes; Toxins; Youth Marketing.

▌ GEOFFREY FERRIS WAYNE

BIBLIOGRAPHY

Bates, Clive, Gregory Connolly, and Martin Jarvis. "Tobacco Additives: Cigarette Engineering and Nicotine Addiction." Action on Smoking and Health (July 1999). Available: <http://www.ash.org.uk/html/regulation/html/additives.html>. An accessible summary analysis of use of additives through study of internal industry documents.

Browne, C. L. The Design of Cigarettes, 3rd ed. Charlotte, N.C.: Hoechst Celanese Corporation, 1990. A widely accepted industry reference on basic cigarette design.

Doull, J., J. P. Frawley, and W. George. List of Ingredients Added to Tobacco in the Manufacture of Cigarettes by Six Major American Cigarette Companies. Washington, D.C.: Covington & Burling, April 12, 1994. A commonly cited list of cigarette additives released by U.S. manufacturers. The list is widely available online; see <http://www.tobacco.org/Resources/599ingredients.html>.

Ferris Wayne, G., and G. N. Connolly. "How Cigarette Design Can Affect Youth Initiation into Smoking: Camel Cigarettes, 1983–1993." Tobacco Control 11 (2002): 32–39. Links the use of additives to an increase in youth initiation.

Hoffmann, D., and I. Hoffmann. "The Changing Cigarette, 1950–1995." Journal of Toxicology and Environmental Health 50, no. 4 (March 1997): 307–364. Describes the use of additives in the context of other product changes.

Leffingwell, John C., Harvey J. Young, and Edward Bernasek. Tobacco Flavoring for Smoking Products. Winston-Salem, N.C.: R.J. Reynolds Tobacco Company, 1972. The definitive industry review of additive flavorants.

Wells, John Kendrick, III. "Subject: Technology Handbook" (22 August 1995). Available: <http://tobaccodocuments.org/product_design/945335.html>. Internal industry study of ammoniation, its use and importance historically.

menthol a form of alcohol imparting a mint flavor to some cigarettes.

physiology the study of the functions and processes of the body.

depressant a substance that depresses the central nervous system. The most common depressant is alcohol.

tar a residue of tobacco smoke, composed of many chemical substances that are collectively known by this term.

carcinogen a substance or activity that can cause cancer. Cigarette smoking has been proven to be carcinogenic, that is, cancer causing.

Additives and Preservatives

Additives are defined by the United States Food and Drug Administration (FDA) as "any substance, the intended use of which results or may reasonably be expected to result, directly or indirectly, in its becoming a component or otherwise affecting the characteristics of any food." In other words, an additive is any substance that is added to food. Direct additives are those that are intentionally added to foods for a specific purpose. Indirect additives are those to which the food is exposed during processing, packaging, or storing. Preservatives are additives that inhibit the growth of bacteria , yeasts, and molds in foods.

Additives and preservatives have been used in foods for centuries. When meats are smoked to preserve them, compounds such as butylated hydroxyanisole (BHA) and butyl gallate are formed and provide both antioxidant and bacteriostatic effects. Salt has also been used as a preservative for centuries. Salt lowers the water activity of meats and other foods and inhibits bacterial growth. Excess water in foods can enhance the growth of bacteria, yeast, and fungi. Pickling, which involves the addition of acids such as vinegar, lowers the pH of foods to levels that retard bacterial growth. Some herbs and spices, such as curry, cinnamon, and chili pepper, also contain antioxidants and may provide bactericidal effects.

Uses of Additives and Preservatives in Foods

Additives and preservatives are used to maintain product consistency and quality, improve or maintain nutritional value, maintain palatability and wholesomeness, provide leavening , control pH, enhance flavor, or provide color. Food additives may be classified as:

1. Antimicrobial agents, which prevent spoilage of food by mold or micro-organisms . These include not only vinegar and salt, but also compounds such as calcium propionate and sorbic acid, which are used in products such as baked goods, salad dressings, cheeses, margarines, and pickled foods.
2. Antioxidants, which prevent rancidity in foods containing fats and damage to foods caused by oxygen . Examples of antioxidants include vitamin C, vitamin E, BHA, BHT (butylated hydroxytolene), and propyl gallate.
3. Artificial colors, which are intended to make food more appealing and to provide certain foods with a color that humans associate with a particular flavor (e.g., red for cherry, green for lime).
4. Artificial flavors and flavor enhancers, the largest class of additives, function to make food taste better, or to give them a specific taste. Examples are salt, sugar, and vanilla, which are used to complement the flavor of certain foods. Synthetic flavoring agents, such as benzaldehyde for cherry or almond flavor, may be used to simulate natural flavors. Flavor enhancers, such as monosodium glutamate (MSG) intensify the flavor of other compounds in a food.
5. Bleaching agents, such as peroxides, are used to whiten foods such as wheat flour and cheese.
6. Chelating agents, which are used to prevent discoloration, flavor changes, and rancidity that might occur during the processing of foods. Examples are citric acid, malic acid, and tartaric acid.
7. Nutrient additives, including vitamins and minerals , are added to foods during enrichment or fortification . For example, milk is fortified with vitamin D , and rice is enriched with thiamin, riboflavin, and niacin .
8. Thickening and stabilizing agents, which function to alter the texture of a food. Examples include the emulsifier lecithin, which, keeps oil and vinegar blended in salad dressings, and carrageen, which is used as a thickener in ice creams and low-calorie jellies.

Regulating Safety of Food Additives and Preservatives

Based on the 1958 Food Additives Amendment to the Federal Food, Drug, and Cosmetic (FD&C) Act of 1938, the FDA must approve the use of all additives. The manufacturer bears the responsibility of proving that the additive is safe for its intended use. The Food Additives Amendment excluded additives and preservatives deemed safe for consumption prior to 1958, such as salt, sugar, spices, vitamins, vinegar, and monosodium glutamate. These substances are considered "generally recognized as safe" (GRAS) and may be used in any food, though the FDA may remove additives from the GRAS list if safety concerns arise. The 1960 Color Additives Amendment to the FD&C Act required the FDA to approve synthetic coloring agents used in foods, drugs , cosmetics, and certain medical devices. The Delaney Clause, which was included in both the Food Additives Amendment and Color Additives Amendment, prohibited approval of any additive that had been found to cause cancer in humans or animals. However, in 1996 the Delaney Clause was modified, and the commissioner of the FDA was charged with assessing the risk from consumption of additives that may cause cancer and making a determination as to the use of that additive.

The FDA continually monitors the safety of all food additives as new scientific evidence becomes available. For example, use of erythrosine (FD&C Red No. 3) in cosmetics and externally applied drugs was banned in 1990 after it was implicated in the development of thyroid tumors in male rats. However, the cancer risk associated with FD&C Red No. 3 is about 1 in 100,000 over a seventy-year lifetime, and its use in some foods, such as candies and maraschino cherries, is still allowed. Tartrazine (FD&C Yellow No. 5) has been found to cause dermatological reactions ranging from itching to hives in a small population subgroup. Given the mild nature of the reaction, however, it still may be used in foods.

Nitrites are also a controversial additive. When used in combination with salt, nitrites serve as antimicrobials and add flavor and color to meats. However, nitrite salts can react with certain amines in food to produce nitrosamines, many of which are known carcinogens . Food manufacturers must show that nitrosamines will not form in harmful amounts, or will be prevented from forming, in their products. The flavoring enhancer MSG is another controversial food additive. MSG is made commercially from a natural fermentation process using starch and sugar. Despite anecdotal reports of MSG triggering headaches or exacerbating asthma , the Joint Expert Committee on Food Additives of the United Nations Food and Agriculture Organization, the World Health Organization, the European Community's Scientific Committee for Food, the American Medical Association, and the National Academy of Sciences have all affirmed the safety of MSG at normal consumption levels.

In the United States, food additives and preservatives play an important role in ensuring that the food supply remains the safest and most abundant in the world. A major task of the FDA is to regulate the use and approval of thousands of approved food additives, and to evaluate their safety. Despite consumer concern about use of food additives and preservatives, there is very little scientific evidence that they are harmful at the levels at which they are used.

The Discovery of Canning

During the late eighteenth century the French army was suffering from scurvy, malnourishment, and outright starvation, and the French government offered a prize of 12,000 francs to anyone who could discover a way to preserve food for the troops. Nicholas Appert, a candymaker, brewer, and baker, reasoned that he should be able to preserve food in bottles, like wine. After fourteen years of experimentation, he finally discovered that if he put food in glass jars reinforced with wire, sealed them with wax, and applied heat, the food didn't spoil. Appert was presented with the 12,000-franc prize by Napoleon himself. However, the secret of preserved food soon leaked to the English, who proceeded to invent the can, and the armies that faced off at Waterloo were both fortified by preserved rations.

—Paula Kepos

In Europe, food additives and preservatives are evaluated by the European Commission's Scientific Committee on Food. Regulations in European Union countries are similar to those in the United States. The Food and Agricultural Organization (FAO) of the United Nations and the World Health Organization (WHO) Expert Committee on Food Additives work together to evaluate the safety of food additives, as well as contaminants, naturally occurring toxicants , and residues of veterinary drugs in foods. Acceptable Daily Intakes (ADIs) are established on the basis of toxicology and other information.

see also Artificial Sweeteners; Fat Substitutes.

M. Elizabeth KunkelBarbara H. D. Luccia

Bibliography

Branen, A. Larry (2002). Food Additives, 2nd edition. New York: Marcel Dekker.

Clydesdale, Fergus M. (1997). Food Additives: Toxicology, Regulation, and Properties. Boca Raton, FL: CRC Press.

Potter, Norman N., and Hotchkiss, Joseph H. (1995) Food Science, 5th edition. New York: Chapman & Hall.