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
growth or by undesirable chemical changes
. In general, preservation is implemented in two modes, chemical and physical. Chemical preservation entails adding chemical compound
s to the product. Physical preservation entails processes such as refrigeration or drying.Erich Lück and Gert-Wolfhard von Rymon Lipinski "Foods, 3. Food Additives" in Ullmann's Encyclopedia of Industrial Chemistry
, 2002, Wiley-VCH, Weinheim. Preservative food additive
s 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. Nitrate
s and nitrite
s are also antimicrobial.Shaw, Ian C. (2012). Food Safety : The Science of Keeping Food Safe. Retrieved from http://www.eblib.com (306- 334) The detailed mechanism of these chemical compounds range from inhibiting growth of the bacteria to the inhibition of specific enzymes.
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.Msagati, Titus A. M. (2012). The Chemistry of Food Additives and Preservatives. Retrieved from http://www.eblib.com Other antioxidants include the phenol
and propyl gallate
. These agents suppress the formation of hydroperoxides. Other preservatives include ethanol
A variety of agents are added to sequester (deactivate) metal ions that otherwise catalyze the oxidation of fats. Common sequestering agents are disodium EDTA
, citric acid
(and citrates), tartaric acid
, and lecithin
Nonsynthetic compounds for food preservation
and ascorbic acid
s target enzymes
that degrade fruits and vegetables, e.g., mono/polyphenol oxidase
which turns surfaces of cut apples and potatoes brown. Ascorbic acid
, which are vitamins, are common preservatives. Smoking
entails exposing food to a variety of phenols, which are antioxidants. Natural preservatives include rosemary
, diatomaceous earth
and castor oil
Traditional preservatives, such as sodium benzoate have raised health concerns in the past. Benzoate was shown in a study to cause hypersensitivity in some asthma sufferers. This has caused reexamination of natural preservatives which occur in vegetables.
History and methods
Preservatives have been used since prehistoric times. Smoked meat
for example has phenol
s and other chemicals that delay spoilage. The preservation of foods has evolved greatly over the centuries and has been instrumental in increasing food security. The use of preservatives other than traditional oils, salts, paints, etc. in food began in the late 19th century, but was not widespread until the 20th century.
The use of food preservatives varies greatly depending on the country. Many developing countries that do not have strong governments to regulate food additives face either harmful levels of preservatives in foods or a complete avoidance of foods that are considered unnatural or foreign. These countries have also proven useful in case studies surrounding chemical preservatives, as they have been only recently introduced.Ashagrie, Z. Z., & Abate, D. D. (2012). IMPROVEMENT OF INJERA SHELF LIFE THROUGH THE USE OF CHEMICAL PRESERVATIVES. African Journal of Food, Agriculture, Nutrition & Development, 12(5), 6409-6423. In urban slums of highly populated countries, the knowledge about contents of food tends to be extremely low, despite consumption of these imported foods.Kumar, H., Jha, A., Taneja, K. K., Kabra, K., & Sadiq, H. M. (2013). A STUDY ON CONSUMER AWARENESS, SAFETY PERCEPTIONS & PRACTICES ABOUT FOOD PRESERVATIVES AND FLAVOURING AGENTS USED IN PACKED /CANNED FOODS FROM SOUTH INDIA. National Journal of Community Medicine, 4(3), 402-406.
In ancient times the sun and wind naturally dried out foods. Middle Eastern and Oriental cultures started drying foods in 1,200 B.C. in the sun. The Romans used a lot of dry fruit. In the Middle Ages, the people made “still houses” where fruits, vegetables, and herbs were could dry out in climates that did not have strong sunlight for drying. Sometimes fires were made to create heat to dry foods. Drying prevents yeasts and molds from growing by removing moisture so bacteria cannot grow. NCHFP Publications|website=nchfp.uga.edu|access-date=2017-07-19}}
Cellars, caves, and cool streams were used for freezing. American estates had ice houses built to store ice and food on the ice. Icehouse was then converted to an “ icebox
”. Icebox was converted in the 1800's to mechanical refrigeration. Clarence Birdseye
found in the 1800's that freezing meats and vegetables at a low temperature made them taste better.
Fermenting was discovered when a few grains of barley were left in the rain and turned into beer. Microorganism
s ferment the starch-derived sugars into alcohols. This is also how fruits are fermented into wine and cabbage into Kimchi
or sauerkraut. Anthropologists believe that as early as 10,00 B.C people began to settle and grow barley. They began to make beer and believed that it was a gift from gods. It was used to preserve foods and to create more nutritious foods from less desirable ingredients. Vitamins are produced through fermentation by microorganism
s making the end product more nutritious.
Pickling occurs when foods are placed in a container with vinegar or another acid. It is thought that pickling came about when people used to place food in wine or beer to preserve it due to them having a low pH
. Containers had to be stoneware or glass (vinegar will dissolve metal from pots). After the food was eaten, the pickling brine
had other uses. Romans would make a concentrated pickle sauce called “ garum
”. It was very concentrated and the dish that it would be used in would only need a few drops to get the fish taste. Due to new foods arriving from Europe in the 16th century, food preservation increased. Ketchup originated from Europe as an oriental fish brine and when it made it to America, sugar was added. Pickling sauces were soon part of many recipes such as chutneys, relish, piccalilli, mustard, and ketchup when different spices were added to them.
The beginning of curing was done through dehydration. Salting was used by early cultures to help desiccate foods. Many different salts were used from different places such as rock salt, sea salt, spiced salt, etc.. People began to experiment and found in the 1800's that some salts gave meat an appealing red color instead of the grey that they were used to. During their experimenting in the 1920's they realized this mixture of salts were nitrate
s (saltpeter) that prevented Clostridium botulinum
Jam and Jelly
The early cultures also used honey or sugar as a preservative. Greece used a quince
and honey mixture with a slight amount of drying and then tightly packed into jars. The Romans used the same technique but instead cooked the honey and quince
mixture to make a solid texture. The Indian and Oriental traders brought sugarcane
to the northern climates where housewives were then able to learn to make preservatives by heating fruit with the sugarcane
Canning started in 1790 from a French confectioner, Nicolas Appert
, when he found that by applying heat to food in sealed glass bottles, the food is free from spoilage. Appert’s ideas were tried by the French Navy with meat, vegetables, fruit, and milk in 1806. An Englishman, Peter Durand
decided to use Appert’s method on tin cans in 1810. Even though Appert found a method that worked, he did not understand why it worked because many believed that the lack of air caused the preservation. In 1864 Louis Pasteur
linked food spoilage/illness to microorganism
s.Different foods are placed into jars or cans and heated to a microorganism
and inactivating enzyme
temperature. They are then cooled forming a vacuum seal which prevents microorganism
s from contaminating the foods.
Public awareness of food preservation
Public awareness of food preservatives is uneven.Kumar, H. N. Harsha; Jha, Anshu Kumar; Taneja, Khushboo K.; Kabra, Krishan; Sadiq, Hafeez M. (2013). A Study On Consumer Awareness, Safety Perceptions & Practices about Food Preservatives and Flavouring Agents used in Packed/Canned Foods from South India. National Journal of Community Medicine, 4(3), 402. Americans have a perception that food-borne illnesses happen more often in other countries. This may be true, but the occurrence of illnesses, hospitalizations, and deaths are still high. It is estimated by the Center for Disease Control
(CDC) that each year there are 76 million illnesses, 325,000 hospitalizations, and 5,000 deaths linked to food-borne illness.Theron, M. M. & Lues, J. F. (2007). Organic acids and meat preservation: A review. Food Reviews International, 23, 141-158.
The increasing demand for ready-to-eat fresh food products has led to challenges for food distributors regarding the safety and quality of their foods. Artificial preservatives meet some of these challenges by preserving freshness for longer periods of time, but these preservatives can cause negative side-effects as well. Sodium nitrite
is a preservative used in lunch meats, ham
s, hot dog
s, and bacon
to prevent botulism
. It serves the important function of controlling the bacteria
that cause botulism
, but sodium nitrite
can react with proteins
, or during cooking at high heats, to form carcinogenic N-nitrosamines
. It has also been linked to cancer
in lab animals.Antinoro, L. (2008). EN Rates 12 Common Food Additives As Safe Or Sorry Ingredients. (Cover story). Environmental Nutrition, 31(5), 1-4. The commonly used sodium benzoate
has been found to extend the shelf life of bottled tomato paste
to 40 weeks without loss of quality.(Bhat, Rajeev; Alias, Abd Karim; Paliyath, Gopinadham (2011). Progress in Food Preservation. Retrieved from http://www.eblib.com However, it can form the carcinogen benzene
when combined with vitamin C
. Many food manufacturers have reformed their products to eliminate this combination, but a risk still exists. Consumption of sodium benzoate
may also cause hyperactivity
. For over 30 years, there has been a debate about whether or not preservatives and other food additives
can cause hyperactivity
. Studies have found that there may be increases in hyperactivity
amongst children who consume artificial colorings and benzoate
preservatives and who are already genetically predisposed to hyperactivity, but these studies were not entirely conclusive. Hyperactivity
only increased moderately, and it was not determined if the preservatives, colorings, or a combination of the two were responsible for the increase.