FOOD ADDITIVES AND PRESERVATIVES

CHAPTER ONE
INTRODUCTION
1.1 FOOD ADDITIVES AND PRESERVATIVES
Additives and preservatives have been in use in foods for centuries. When meats are
smoked as means of preserving them, compounds such as butyl gallate and butylated
hydroxyl anisole (BHA) are formed and provide both bacteriostatic and antioxidant effects.
Salt has been in use as a preservative for centuries. Salt preserves by lowering the water
activity (aw) of meats and other foods as well as inhibits the growth of bacteria. Excess water
in foods often can encourage the growth of microorganisms such as fungi and bacteria.
Pickling, which involves addition of acids such as vinegar, lowers pH of foods to levels
capable of retarding the growth of bacteria. Some herbs and spices, such as cinnamon, chili
pepper, and curry, contain antioxidants and may offer bactericidal effects.
Food additives are substances which are added to food to preserve its flavor or
enhance its appearance, taste, or other qualities. Some food additives have been under use for
centuries, e.g., preserving foods by pickling with vinegar, brining or salting, as with bacon,
preserving sweet or using sulfur dioxide as in wines. With the advent of many processed
foods in second half of twentieth century, several more additives were introduced; both
natural and artificial (or synthetic) origins. Also, food additives include the substances that
may be indirectly introduced to foods (known as indirect additives) during the manufacturing
process, by packaging, or during transport or storage (FDA, 2017; FDA, 2018). The US Food
and Drug Administration (FDA) describes food additives as any substance, intended use of
which results or might reasonably be expected to result, indirectly or directly, in its becoming
a constituent or otherwise affecting characteristics of any food.
The WHO stated that substances which are added to foods to improve or maintain the
taste, texture, appearance, safety, or freshness of foods are known as food additives (WHO,
2018). Some food additives have been used for centuries for food preservation, such as salt in
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meats like bacon or dried fish, sulfur dioxide in wine, or sugar in marmalade. Food additives
may also be used to confer a specific functional property in foods (Chinaza, 2019b; Chinaza
et al., 2019a). Over time, many food additives have been developed to meet the requirements
of food production and food industries, as producing foods on large scale is quite different
from making on a small scale at home or for household. Additives are required to ensure the
processed foods remain safe, in good condition, and fresh throughout its journey from the
factories or industries, during the course of transportation to shops and warehouses, and
finally to the consumers, who often look out for fresh, safe, nutritious, and wholesome foods.
The use of additives in foods is only justified when their use does not mislead
consumers, has technological need, and serves well-defined technological function, such as to
enhance the stability of the food or preserve the nutritional quality of the food. Food additives
can be derived from animals, plants, or minerals, or can be synthetic. They are added to food
intentionally to perform some technological purposes which the consumers often take for
granted (WHO, 2018), or unintentionally added through food-package interactions or from
other sources such as pesticides used in growing crops, mycotoxins such as aflatoxin, patulin
(Chinaza et al., 2019b) found in grains and other foods; also, some components such as
methanol and ethyl carbamate (Igwe et al., 2018a; Igwe et al., 2018b) may be formed in some
traditional beverages and become part of the foods.
There are several thousand food additives in use, which are all designed to do specific
job in making foods more appealing, safer, or nutritious. Bisphenols, perfluoroalkyl
chemicals (PFCs), and phthalates are indirect additives used in packaging or manufacturing.
In July 2018 the American Academy of Pediatrics (AAP) called for more study of
Bisphenols, perfluoroalkyl chemicals (PFCs), and phthalates, along with food coloring and
nitrates, as they might harm the children during development (American Academy of
Pediatrics, 2018). The safety assessments completed by the Joint Expert Committee on Food
Additives (JECFA) are used by the Codex Alimentarius Commission, a joint
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intergovernmental body of the FAO and WHO that sets food standard, to establish the levels
for maximum use of preservatives and additives in food and drinks (WHO, 2018).
Codex standards serve as reference for national standards for the consumer protection,
and for international trade in foods, so that consumers everywhere will be confident that the
foods they consume meet the agreed standards for quality and safety, no matter where they
were produced (WHO, 2018). Once a food additive is found safe for use by the JECFA and
the maximum use levels established in Codex General Standard for Food Additives, the
national food regulations require to be implemented permitting actual use of food additive.
The use of food additives in the US is closely regulated by the governmental agencies
responsible for health, agriculture, and consumer safety. This is also the case in other
developed nations in Europe, Canada, etc. (Encyclopedia, 2020). Chemicals cannot be used
as food additives in those countries except regulators are convinced, they have been shown to
be toxicologically safe, with wide margin of security.
Additionally, chemicals added to commercially made foods must be listed on
packaging so that the consumers will know what is present in the foods they choose to eat
(Branen, 2002; Encyclopedia, 2020; Clydesdale, 1997; Potter and Hotchkiss, 1995). As a
result of the intrinsic nature of low-level, toxicological risk, especially those associated with
the diseases that may take long time to develop, researchers and scientists are never able to
show that trace exposures to any chemical or additive are absolutely safe—there is often a
level of risk, no matter how small.
1.2 CATEGORIES OF FOOD ADDITIVES AND PRESERVATIVES
Food additives can be further divided into many groups, though there is some
overlapping because some additives have at least two effects; e.g., salt is both a preservative
and a flavor (Erich and Gert-Wolfhard, 2002; FDA, 2017); citric acid is a preservative, adds
flavor, and an acidity regulator.
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a) Acidity regulators: Acidity regulators are used to control the pH of foods for stability or
to affect the activities of enzymes.
b) Antioxidants: Antioxidants, such as vitamins E and C, BHA, BHT, are preservatives by
inhibiting food degradation by oxygen.
c) Bulking agents: The bulking agents (e.g. starch) are additives which increase the bulk of
food without affecting its taste.
d) Food coloring: The food colorings are added to foods to replace the colors lost during
preparation or processing, or to make food more attractive.
e) Anticaking agents: The anticaking agents keep powders, e.g., milk powder, from sticking
or caking.
f) Foaming and antifoaming agents: Antifoaming agents prevent or reduce foaming in
foods. Foaming agents do the opposite.
g) Acidulents: Acidulants confer acid or sour taste. Common acidulents include citric acid,
tartaric acid, vinegar, malic acid, lactic acid, and fumaric acid.
h) Fortifying agents: Minerals, vitamins, and dietary supplements to increase nutritional
value of foods.
i) Flavor enhancers: Flavor enhancers improve the existing flavors of foods. A common
example is monosodium glutamate (MSG). A number of flavor enhancers have their own
flavors which are independent of the food.
j) Color retention agents: Contrary to colorings, the color retention agents are used in foods
to preserve the existing color of the foods.
k) Flour treatment agents: These treatment agents are added to the flours to improve their
color or their use in baking.
l) Emulsifiers: Emulsifiers allow oils and water to remain mixed together in emulsion, as in
ice cream, mayonnaise, and homogenized milk.
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m) Tracer gas: Tracer gas allow package integrity testing to prevent the foods from exposure
to the atmosphere, thus guaranteeing shelf life.
n) Preservatives: Preservatives are one of the most important components of foods,
especially commercially made foods. Preservatives inhibit or prevent spoilage of food due to
bacteria, fungi, and other spoilage microorganisms.
o) Flavors: Flavors are food additives that give food a specific smell or taste, and can be
derived from natural ingredients or made artificially.
p) Glazing agents: Glazing agents provide protective coating or shiny appearance to foods.
q) Thickeners: Thickening agents are food additives which, when added to the food mixture,
increase the viscosity of the food without substantially modifying other properties of the
food.
r) Humectants: Humectants prevent the foods from drying out.
s) Stabilizers: Stabilizers, food thickeners and gelling agents, such as agar or pectin give
foods firmer texture. They help to stabilize emulsions, although they are not true emulsifiers.
t) Sweeteners: Sweeteners are added to food for flavoring. Sweeteners other than sugar, such
as sugar alcohols, are added to keep the calories (or food energy) low, (Chinaza and Echeta,
2019; Awuchi, 2017) or because of their beneficial effects regarding tooth decay, diabetes
mellitus, or diarrhea.
1.3 USES OF FOOD ADDITIVES AND PRESERVATIVES
Uses of food additives and preservatives Additives and preservatives are used in foods
to maintain or improve nutritional value, maintain product quality and consistency, provide
leavening, control pH, maintain palatability and wholesomeness, provide color, or enhance
flavor. Food additives can be classified as:
a) Thickening and stabilizing agents, which alter the food texture. Examples include
carrageen, which is used as thickener in low-calorie jellies and ice creams, and the emulsifier
lecithin, used to keep oil and vinegar blended in the salad dressings.
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b) Chelating agents are used to prevent discoloration, rancidity, and flavor changes that may
occur during food processing. Examples are malic acid, citric acid, and tartaric acid
c) Bleaching agents, e.g. peroxides, are used in foods to whiten the foods such as cheese,
wheat flour.
d) Artificial colors are intended to make foods more appealing and to provide some foods
with color which humans associate with a particular flavor; for example, green for lime,
yellow for banana, brown for chocolate or coffee, red for cherry.
e) Antioxidants, which prevent damage to foods caused by oxygen and rancidity in foods
containing fats. Examples of antioxidants include BHA (butylated hydroxyl anisole), BHT
(butylated hydroxyl tolene), propyl gallate, vitamin C, and vitamin E.
f) Antimicrobial agents, which prevent the spoilage of food by microorganisms. These
include vinegar, salt, calcium propionate, sorbic acid, etc., which are used in food products
such as salad dressings, cheeses, baked goods, margarines, and pickled foods
g) Nutrient additives, including micronutrients (vitamins and minerals), are added to food
during fortification or enrichment. For instance, rice is enriched with thiamin, riboflavin, and
niacin; milk is fortified with vitamin D; salt is iodized.
h) Artificial flavors and flavor enhancers are the largest class of food additives. They function
to give foods a specific taste or to make foods taste better. Common examples are sugar, salt,
and vanilla used to complement flavor of some foods. The synthetic flavoring agents, e.g.
benzaldehyde for almond or cherry flavor, might be used to simulate the natural flavors.
Flavor enhancers, e.g. monosodium glutamate (MSG), intensify flavor of other compounds in
foods.
1.4 PURPOSE OF FOOD ADDITIVES
The purpose of food additives Direct additives are the food additives that are
intentionally added to food for specific purpose. Indirect additives are the ones to which the
foods are exposed to during processing, storing, or packaging. Preservatives are the additives
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