View source for Preservative

{{short description|Substance designed to prevent decomposition}}
{{Lead extra info|date=May 2021|reason=This is the only part of the article that talks about preservatives that are not related to food.}}

A '''preservative''' is a [[Chemical substance|substance]] or a chemical that is added to products such as food products, beverages, [[pharmaceutical drugs]], paints, biological samples, cosmetics, wood, and many other products to prevent [[decomposition]] by [[microbial]] growth or by undesirable [[Chemical reaction|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.<ref name=Ullmann>Erich Lück and Gert-Wolfhard von Rymon Lipinski "Foods, 3. Food Additives" in ''Ullmann's Encyclopedia of Industrial Chemistry'', 2002, Wiley-VCH, Weinheim. {{doi| 10.1002/14356007.a11_561}}</ref> Preservative [[food additive]]s reduce the risk of [[Foodborne illness|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.

==Food preservation==
{{Split portions|Food preservation|date=May 2021|discuss=Talk:Preservative#Split the content?|portion=the specifics in the "food preservation" section|existing=y}}{{Main|Food preservation}}
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, {{clarify|date=November 2023}} etc. in food began in the late 19th century, but was not widespread until the 20th century.<ref>{{cite journal | author = Evans, G., de Challemaison, B., & Cox, D. N. | date = 2010 | title = Consumers' ratings of the natural and unnatural qualities of foods | journal = Appetite | volume = 54 | issue = 3 | pages = 557–563 | doi = 10.1016/j.appet.2010.02.014| pmid = 20197074 | s2cid = 41078790 }}</ref>

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.<ref>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.</ref> In urban slums of highly populated countries, the knowledge about contents of food tends to be extremely low, despite consumption of these imported foods.<ref>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.</ref>

===Antimicrobial preservatives===
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.<ref name= Msagati/><ref name="CEN-1">{{cite journal|last=Dalton|first=Louisa|title=Food Preservatives|journal=Chemical and Engineering News|date=November 2002|volume=80|issue=45|pages=40|url=http://pubs.acs.org/cen/science/8045/8045sci2.html|access-date=9 February 2012|doi=10.1021/cen-v080n045.p040|archive-date=5 April 2019|archive-url=https://web.archive.org/web/20190405015035/http://pubs.acs.org/cen/science/8045/8045sci2.html|url-status=live|url-access=subscription}}</ref><ref>{{cite web|title=Using Preservatives|url=http://www.understandingfoodadditives.org/pages/Ch2p5-3.htm|access-date=9 February 2012|archive-date=28 March 2019|archive-url=https://web.archive.org/web/20190328230920/http://www.understandingfoodadditives.org/pages/Ch2p5-3.htm|url-status=live}}</ref> [[Nitrate]]s and [[nitrite]]s are also antimicrobial.<ref>Shaw, Ian C. (2012). Food Safety : The Science of Keeping Food Safe. Retrieved from http://www.eblib.com {{Webarchive|url=https://web.archive.org/web/20160207133203/http://www.eblib.com/ |date=2016-02-07 }} (306- 334)</ref> The detailed mechanism of these chemical compounds range from inhibiting growth of the bacteria to the inhibition of specific enzymes.

{| class="wikitable"
|-
! [[E number]]
! chemical compound
! comment
|-
| E200 – E203
| [[sorbic acid]], [[sodium sorbate]] and sorbates
| common for [[cheese]], [[wine]], baked goods, personal care products
|-
| E210 – E213
| [[benzoic acid]] and [[benzoates]]
| used in acidic foods such as [[Fruit preserves|jams]], [[salad dressing]], [[juice]]s, [[Pickling|pickles]], [[carbonated drinks]], [[soy sauce]]
|-
| E214 – E219
| [[paraben]]s
| stable at a broad [[pH]] range
|-
| E220 – E228
| [[sulfur dioxide]] and [[sulfite]]s
| common for fruits, wine
|-
| E249 – E250
| [[nitrite]]s
| speed up the [[Curing (food preservation)|curing]] of meat and also impart an attractive colour, no effect on botulism bacteria<ref name="Wilson">{{cite news |last=Wilson |first=Bee |date=2018-03-01 |title=Yes, bacon really is killing us |language=en-GB |work=The Guardian |location=London |url=https://www.theguardian.com/news/2018/mar/01/bacon-cancer-processed-meats-nitrates-nitrites-sausages |url-status=live |access-date=2021-02-14 |archiveurl=https://web.archive.org/web/20210210183650/https://www.theguardian.com/news/2018/mar/01/bacon-cancer-processed-meats-nitrates-nitrites-sausages |archivedate=2021-02-10 |issn=0261-3077 |quote=In trade journals of the 1960s, the firms who sold nitrite powders to ham-makers spoke quite openly about how the main advantage was to increase profit margins by speeding up production.}}</ref><ref>{{cite news |last=Doward |first=Jamie |date=2019-03-23 |title=Revealed: no need to add cancer-risk nitrites to ham |work=The Observer |location=London |url=https://www.theguardian.com/food/2019/mar/23/nitrites-ham-bacon-cancer-risk-additives-meat-industry-confidential--report |url-status=live |access-date=2021-02-14 |archiveurl=https://web.archive.org/web/20210126134441/https://www.theguardian.com/food/2019/mar/23/nitrites-ham-bacon-cancer-risk-additives-meat-industry-confidential--report |archivedate=2021-01-26 |quote=The results show that there is no change in levels of inoculated ''C. botulinum'' over the curing process, which implies that the action of nitrite during curing is not toxic to ''C. botulinum'' spores at levels of 150ppm [parts per million] ingoing nitrite and below.}}</ref>
|-
| E251 – E252
| [[nitrate]]s
| used in meats
|-
| E270
| [[lactic acid]]
| -
|-
| E280 – E283
| [[propionic acid]] and [[propionate]]s
| baked goods
|-
| E338
| [[phosphoric acid]]
| used in some jams, preserves and carbonated drinks; also used for acidification and for flavouring.
|}
===Antioxidants===
[[Image:Lipid peroxidation.svg|thumb|right|The [[Radical (chemistry)|free radical]] pathway for the first phase of the oxidative rancidification of fats.  This process is slowed by antioxidants.]]

The oxidation process spoils most food, especially those with a high fat content.  Fats quickly [[rancidification|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.<ref name=Bhat/> Thus, antioxidants are commonly added to oils, cheese, and chips.<ref name= Msagati>Msagati, Titus A. M. (2012). The Chemistry of Food Additives and Preservatives. Retrieved from http://www.eblib.com {{Webarchive|url=https://web.archive.org/web/20160207133203/http://www.eblib.com/ |date=2016-02-07 }}</ref> Other antioxidants include the [[phenol]] derivatives [[Butylated hydroxyanisole|BHA]], [[Butylated hydroxytoluene|BHT]], [[tert-Butylhydroquinone|TBHQ]] and [[propyl gallate]].  These agents suppress the formation of hydroperoxides.<ref name="CEN-1" />

{| class="wikitable"
|-
! E number
! chemical compound
! comment
|-
| E300-304
| [[ascorbic acid]], [[sodium ascorbate]]
| cheese, chips
|-
| E321
| [[butylated hydroxytoluene]], [[butylated hydroxyanisole]]
| also used in food packaging
|-
| E310-312
| [[gallic acid]] and sodium gallate
| oxygen scavenger
|-
| E220 – E227
| [[Sulfite food and beverage additives|sulfur dioxide and sulfite]]s
| beverages, wine
|-
| E306 – E309
| [[tocopherol]]s
| vitamin E activity
|-
|}
A variety of agents are added to sequester (deactivate) metal ions that otherwise catalyze the oxidation of fats.  Common sequestering agents are [[EDTA|disodium EDTA]], [[citric acid]] (and citrates), [[tartaric acid]], and [[lecithin]].<ref name=Ullmann/>

===Nonsynthetic compounds for food preservation===
{{cleanup section|reason=Might be better to just add into the notes part of the above tables, with language like "found naturally in X food / X traditional process". Benzoate is natural too!|date=November 2023}}
[[Citric acid|Citric]] and [[ascorbic acid]]s target [[enzyme]]s that degrade fruits and vegetables, e.g., [[mono/polyphenol oxidase]] which turns surfaces of cut apples and potatoes brown. [[Ascorbic acid]] and [[tocopherol]], which are vitamins, are common preservatives.  [[Smoking (cooking)|Smoking]] entails exposing food to a variety of phenols, which are antioxidants.  Natural preservatives include [[rosemary]] and [[oregano]] extract,<ref>{{cite magazine|author=Riva Pomerantz|date=Nov 15, 2017|title=KOSHER IN THE LAB|magazine=[[Ami (magazine)|Ami]]|issue=342|page=88}}</ref> [[hops]], [[salt]], [[sugar]], [[vinegar]], [[Ethanol|alcohol]], [[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.<ref>{{cite journal|last=P'EREZ-D'IAZ|first=I.M|author2=MCFEETERS, R.F|title=Preservation of Acidified Cucumbers with a Natural Preservative Combination of Fumaric Acid and Allyl Isothiocyanate that Target Lactic Acid Bacteria and Yeasts.|journal=Journal of Food Science|date=May 2010|volume=75|issue=4|pages=M204–M208|doi=10.1111/j.1750-3841.2010.01587.x|pmid=20546411|url=https://naldc-legacy.nal.usda.gov/naldc/download.xhtml?id=43163&content=PDF|access-date=2018-12-29|archive-date=2021-02-19|archive-url=https://web.archive.org/web/20210219100130/https://naldc-legacy.nal.usda.gov/naldc/download.xhtml?id=43163&content=PDF|url-status=dead|url-access=subscription}}</ref>

===Public awareness of food preservation===
{{globalize section|date=May 2021}}
Public awareness of food preservatives is uneven.<ref>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.</ref> 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 [[Centers for Disease Control]] (CDC) that each year there are 76 million illnesses, 325,000 hospitalizations, and 5,000 deaths linked to food-borne illness.<ref name="Theron, M. M. 2007">Theron, M. M. & Lues, J. F. (2007). Organic acids and meat preservation: A review. Food Reviews  International, 23, 141-158.</ref>

Food suppliers are facing difficulties with regards to the safety and quality of their products as a result of the rising demand for ready-to-eat fresh food products. 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, [[sausage]]s, [[hot dog]]s, and [[bacon]] to prevent [[botulism]] and other foodborne pathogens. It serves the important function of controlling the [[bacteria]] that cause [[botulism]], but [[sodium nitrite]] can react with [[protein]]s, or during cooking at high heats, to form [[carcinogen]]ic N-[[nitrosamine]]s.<ref name=Field>{{cite book | author = Field, Simon Quellen | date = 2008 | title = Why There's Antifreeze in Your Toothpaste: The Chemistry of Household Ingredients | location = Chicago | publisher = Chicago Review Press}}</ref>{{medrs|date=March 2015}} It has also been linked to [[cancer]] in lab animals.<ref name= Antinoro>Antinoro, L. (2008). EN Rates 12 Common Food Additives As Safe Or Sorry Ingredients. (Cover story). Environmental Nutrition, 31(5), 1-4.</ref>
* The commonly used [[sodium benzoate]] has been found to extend the shelf life of bottled [[tomato paste]] to 40 weeks without loss of quality.<ref name=Bhat>(Bhat, Rajeev; Alias, Abd Karim; Paliyath, Gopinadham (2011). Progress in Food Preservation. Retrieved from http://www.eblib.com {{Webarchive|url=https://web.archive.org/web/20160207133203/http://www.eblib.com/ |date=2016-02-07 }}</ref> However, it can form the [[carcinogen]] [[benzene]] when combined with [[vitamin C]].{{citation needed|date=June 2014}} Many food manufacturers have reformed their products to eliminate this combination, but a risk still exists.<ref name= Antinoro/>

== Preservation of other products ==

Water-based home and personal care products use [[broad-spectrum]] preservatives, such as [[isothiazolinone]]s and [[formaldehyde releaser]]s, which may cause sensitization, leading to [[allergy|allergic]] skin.<ref>{{Cite web|url=https://cen.acs.org/business/consumer-products/search-new-cosmetic-preservatives/96/i39|title=The search is on for new cosmetic preservatives|website=Chemical & Engineering News|language=en|access-date=2021-10-25|archive-date=2021-10-25|archive-url=https://web.archive.org/web/20211025193552/https://cen.acs.org/business/consumer-products/search-new-cosmetic-preservatives/96/i39|url-status=live}}</ref>
{|class=wikitable
! Substance !! Use
|-
|[[paraben]]s
|personal care products
|-
|isothiazolinones ([[Methylchloroisothiazolinone|MIT]], [[Methylchloroisothiazolinone|CMIT]], [[Benzisothiazolinone|BIT]])
|''not for food'': home and personal care products, paints/coatings
|-
|formaldehyde releasers ([[DMDM hydantoin]])
|''not for food'': home and personal care products
|}

==See also==
*{{anl|Stabilizer (chemistry)}}
*{{anl|wood preservation}}
*{{anl|food preservation}}

==References==
{{reflist}}

==External links==
* {{Commons category-inline|Preservatives}}

{{Consumer Food Safety}}
{{Authority control}}

[[Category:Preservatives| ]]
[[Category:Chemical substances]]
[[Category:Food ingredients]]