Preservative
A preservative is a substance added to food and other products to prevent or slow down spoilage, thereby extending their shelf life. These additives can be either natural, like salt and sugar, or artificial, developed to inhibit the growth of microorganisms and prevent oxidation, which can lead to rancidity and discoloration. Preservatives are widely used in various products, including foods, beverages, medications, and cosmetics, and are regulated by authorities such as the U.S. Food and Drug Administration (FDA), which mandates clear labeling.
Historically, methods of food preservation have evolved from ancient techniques like drying, curing, and pickling to modern practices, including canning and refrigeration. Some commonly used preservatives include propionic acid, benzoates, nitrites, and sulfites, each serving specific functions like inhibiting mold growth or enhancing flavor. While most preservatives are considered safe at moderate levels, some have been linked to health concerns, such as potential cancer risks. It’s important to be aware of individual sensitivities, especially to sulfites, which can cause adverse reactions in a small percentage of the population. Overall, preservatives play a significant role in food safety and availability, reflecting both historical practices and contemporary scientific advancements.
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Preservative
A preservative is a type of food additive that is used to prevent or slow spoilage. Preservatives lengthen the life span of many foods and beverages, so they do not go rancid, discolor, or change in texture. Both natural and artificial preservatives exist. Many foods, except organic and some fresh foods, contain some type of preservative. They can also be found in medications, cosmetics, and other products. The US Food and Drug Administration (FDA) regulates preservatives and requires them to be labeled. While some have been linked to an increased cancer risk, they are considered mostly safe for consumption in moderate levels. Prior to the development of preservatives, individuals used many techniques to make foods last longer such as curing, canning, and pickling.
Background
People have been practicing the art of preserving food since ancient times. Prior to learning preservation methods, food had to be eaten immediately. As soon as food is harvested, it begins to spoil. Humans had to determine ways to stop or slow down this process to extend the life of their food. When food became scarce, people usually moved to places where they could find something to eat, such as warmer climates during the cold months. Preservation allowed people to keep food for longer periods, thus permitting them to remain in one place and build communities.
Basic food preservation methods emerged throughout the years. In ancient times, drying was a popular way to keep food for later consumption. This method can be traced to Asia around 12,000 B.C.E. The sun and wind were used to naturally dry fish and game meat as well as fruits and vegetables. During the Middle Ages, the Romans built huts to house foods for drying and used fire to aid in the process; this also smoked the foods and further preserved them.
People who lived in cold climates took advantage of the low temperatures to freeze foods and prolong their storage. Individuals also stored foods in cool cellars and caves. Later, icehouses and iceboxes were built to keep food on ice. These eventually became the modern refrigerator.
The process of fermentation was discovered by accident when barley outside in the rain produced beer. The moist atmosphere helped microorganisms in the grains grow and then ferment with the sugars in the grains to produce alcohol. This process also made foods more nutritious because the microorganisms produced vitamins as they fermented.
Pickling was another technique used to keep food fresh. Early on, people placed food in wine and beer to help extend its life. When the liquid soured, it gave the food a pleasantly sour taste. Vinegar and other acids were soon used to pickle foods. Individuals began to use the pickling juices to make sauces, condiments, relishes, and more.
When curing, also known as dehydration, people used salt to draw the moisture out of foods to prevent them from becoming rancid. The use of sugar and honey to keep foods fresh was also common during this time. This led to the creation of jams and jellies when people heated fruit with sugar to preserve it. Canning is a newer form of preserving foods that was developed in the late 1700s by French chef Nicolas Appert. He discovered that he could use heat to seal foods in glass bottles to extend their shelf life.
Overview
Although natural preservatives such as salt, honey, and sugar had been used for centuries, over time, artificial preservatives were developed to keep food from spoiling. Preservatives work in several ways. They act as antimicrobials to block the growth of molds, bacteria, and yeasts. They work as antioxidants to slow the oxidation process (chemical breakdown of food in the presence of oxygen) of fats and lipids that causes spoilage to foods. They also serve as chelating agents to prevent the natural ripening and enzymatic processes that immediately begin after food is harvested.
Propionic acids naturally occur in many types of foods such as strawberries, apples, grains, and cheese. Propionic acids prevent mold in breads and baked items. Benzoates (benzoic acids), which are found in cranberries, and sorbates (sorbic acids) block the growth of fungus. Both are used in numerous foods, such as beverages, jams, pickled foods, meats, condiments, cheeses, and margarines, to keep them fresh.
Nitrites and nitrates keep cured and processed meats, such as bacon and deli meats, a pink color and prevent them from turning brown. Derived from salt, they also enhance flavor. Nitrites and nitrates prevent the bacterium Clostridium botulinum from growing on foods.
Sulfur dioxide, a type of sulfite, is a preservative found in dried fruits, wines, and other processed foods. The compound inhibits microbial growth at the cellular level. It can interfere with the way cells work and even destroy genetic material. Sulfites can keep dried fruits such as golden raisins from browning by preventing the Maillard reaction, which is the chemical process between amino acids and reducing sugars. It gives raisins their dark color and distinct flavor. Some people (about one in one hundred) have sensitivities or allergies to sulfites. These can cause mild to severe reactions such as breathing problems.
Butylated hydroxytoluene (BHT) and butylated hydroxyanisole (BHA) slow oxidation in foods to prevent them from spoiling. They are commonly used to prevent oils from going bad. Fatty acids and lipids are damaged by oxygen, which creates an off-putting smell and flavor. Other examples of antioxidant preservatives include tert-Butylhydroquinone (TBHQ) and propyl gallate.
Some foods contain enzymes that cause them to metabolize after harvest. The enzyme phenolase contributes to apples or potatoes turning brown when they are cut and their flesh is exposed to the air. Citric acid and ascorbic acid (vitamin C) can be used to counteract phenolase and prevent the browning process. The chelating agent ethylenediaminetetraacetic acid (EDTA) is used to stop bacterial and fungal enzymes from spoiling foods. EDTA can also be used to prevent discoloration to foods and other products.
Bibliography
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