Editing Sodium nitrite (section)

=== Food additive and preservative ===
Sodium nitrite is used to speed up the [[Curing (food preservation)|curing]] of meat,<ref name=Wilson>{{cite news |vauthors=Wilson B |date=1 March 2018 |title=Yes, bacon really is killing us |url=https://www.theguardian.com/news/2018/mar/01/bacon-cancer-processed-meats-nitrates-nitrites-sausages |url-status=live |work=[[The Guardian]] |location=London |language=en-GB |issn=0261-3077 |archive-url=https://web.archive.org/web/20210210183650/https://www.theguardian.com/news/2018/mar/01/bacon-cancer-processed-meats-nitrates-nitrites-sausages |archive-date=10 February 2021 |access-date=14 February 2021 |quote=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> inhibit the germination of ''[[Clostridium botulinum]]'' spores, and also impart an attractive pink color.<ref>{{cite journal |vauthors=Lerfall J, Østerlie M |title=Use of sodium nitrite in salt-curing of Atlantic salmon (Salmo salar L.) – Impact on product quality |journal=[[Food Chemistry (journal)|Food Chemistry]] |date=February 2011 |volume=124 |issue=3 |pages=759–766 |doi=10.1016/j.foodchem.2010.06.092}}</ref><ref name="FSAINitriteInMeat">{{cite web| title = Use and Removal of Nitrite in Meat Products| url = https://www.fsai.ie/faq/use_and_removal_of_nitrite.html#prevent_botulism| access-date = 23 April 2023| archive-url = https://web.archive.org/web/20230309190327/https://www.fsai.ie/faq/use_and_removal_of_nitrite.html| archive-date = 9 March 2023}}</ref> Nitrite reacts with the meat [[myoglobin]] to cause color changes, first converting to nitrosomyoglobin (bright red), then, on heating, to nitrosohemochrome (a pink pigment).<ref>{{cite journal |vauthors=Bailey ME, Frame RW, Naumann HD |title=Cured Meat Pigments, Studies of the Photooxidation of Nitrosomyoglobin |journal=[[Journal of Agricultural and Food Chemistry]] |date=January 1964 |volume=12 |issue=1 |pages=89–93 |doi=10.1021/jf60131a026|bibcode=1964JAFC...12...89B }}</ref>

Historically, [[salt]] has been used for the preservation of meat. The salt-preserved meat product was usually brownish-gray in color. When sodium nitrite is added with the salt, the meat develops a red, then pink color, which is associated with cured meats such as ham, bacon, hot dogs, and bologna.<ref>{{cite web|url=http://www.math.unl.edu/~jump/Center1/Labs/MeatPigmentChemistry.pdf|title="Meat Pigment Chemistry", taken from IFT Mini-Experiments in Food Science Series|access-date=28 January 2019|archive-date=3 December 2019|archive-url=https://web.archive.org/web/20191203111916/http://www.math.unl.edu/~jump/Center1/Labs/MeatPigmentChemistry.pdf|url-status=dead}}</ref>

In the early 1900s, irregular curing was commonplace. This led to further research surrounding the use of sodium nitrite as an [[Food additive|additive]] in food, standardizing the amount present in foods to minimize the amount needed while maximizing its food additive role.<ref name="Sindelar Human safety">{{cite journal | vauthors = Sindelar JJ, Milkowski AL | title = Human safety controversies surrounding nitrate and nitrite in the diet | journal = Nitric Oxide | volume = 26 | issue = 4 | pages = 259–266 | date = May 2012 | pmid = 22487433 | doi = 10.1016/j.niox.2012.03.011}}</ref> Through this research, sodium nitrite has been found to give taste and color to the meat and inhibit lipid oxidation that leads to rancidity, with varying degrees of effectiveness for controlling growth of disease-causing [[microorganisms]].<ref name="Sindelar Human safety" /> The ability of sodium nitrite to address the above-mentioned issues has led to production of meat with extended storage life and has improved desirable color and taste. According to scientists working for the meat industry,<ref>{{cite web |url=https://www.ctvnews.ca/lifestyle/science-says-are-hot-dogs-healthier-without-added-nitrites-1.3483769|title=Science Says: Are hot dogs healthier without added nitrites? {{!}} Lifestyle from CTV News|website=www.ctvnews.ca|date=30 June 2017}}</ref> nitrite has improved [[food safety]].<ref name="Sindelar Human safety" /> This view is disputed in the light of the possible carcinogenic effects caused by adding nitrites to meat.<ref name=Wilson/>

Nitrite has the [[E number]] E250. [[Potassium nitrite]] (E249) is used in the same way. It is approved for usage in the European Union,<ref>{{cite web|title=Approved additives and E numbers|url=https://www.food.gov.uk/business-guidance/approved-additives-and-e-numbers|access-date=9 January 2023|website=Food Standards Agency|language=en}}</ref><ref>{{cite web | title = Opinions of the Scientific Committee for Food on: Nitrates and Nitrite |url=http://ec.europa.eu/food/fs/sc/scf/reports/scf_reports_38.pdf| work = Food Science and Techniques | publisher = European Commission|access-date=1 April 2018}}</ref> USA,<ref>US Food and Drug Administration: {{cite web |url=https://www.fda.gov/Food/FoodIngredientsPackaging/FoodAdditives/ucm191033.htm#ftnT |archive-url=https://web.archive.org/web/20100108135705/http://www.fda.gov/Food/FoodIngredientsPackaging/FoodAdditives/ucm191033.htm#ftnT |url-status=dead |archive-date=8 January 2010 |title=Listing of Food Additives Status Part II |website=[[Food and Drug Administration]] |access-date=27 October 2011}}</ref> and Australia and New Zealand.<ref>{{cite web |title=Australia New Zealand Food Standards Code - Standard 1.2.4 - Labelling of Ingredients |url=http://www.legislation.gov.au/Details/F2011C00827/Html/Text |access-date=9 January 2023 |website=www.legislation.gov.au |language=en}}</ref>

In meat processing, sodium nitrite is never used in a pure state but always mixed with common [[salt]]. This mixture is known as nitrited salt, [[curing salt]] or nitrited curing salt. In Europe, nitrited curing salt contains between 99.1% and 99.5% common salt and between 0.5% and 0.9% nitrite. In the US, nitrited curing salt is dosed at 6.25%<ref name="Gisslen2006">{{cite book | vauthors = Gisslen W | title = Professional Cooking, College Version | chapter = Sausages and Cured Foods  | chapter-url = https://books.google.com/books?id=hxcH5o9QeywC&pg=PA827 | page = 827 | year = 2006 | location = Hoboken, New Jersey | publisher = John Wiley & Sons | isbn = 9780471663744 | access-date = 2013-08-16 }}</ref> and must be remixed with salt before use.<ref>{{cite book |vauthors=Coudray G |title=Who poisoned your bacon? |date=February 2021 |publisher=Icon Books |isbn=978-1785786112 |pages=xv |url=https://iconbooks.com/ib-title/who-poisoned-your-bacon/}}</ref>

==== Color and taste ====
The appearance and taste of meat is an important component of consumer acceptance.<ref name="Sindelar Human safety" /> Sodium nitrite is responsible for the desirable red color (or shaded pink) of meat.<ref name="Sindelar Human safety" /> Very little nitrite is needed to induce this change.<ref name="Sindelar Human safety" /> It has been reported that as little as 2 to 14 parts per million (ppm) is needed to induce this desirable color change.<ref name="Sindelar One" /> However, to extend the lifespan of this color change, significantly higher levels are needed.<ref name="Sindelar One" /> The mechanism responsible for this color change is the formation of nitrosylating agents by nitrite, which has the ability to transfer [[nitric oxide]] that subsequently reacts with myoglobin to produce the cured meat color.<ref name="Sindelar One" /> The unique taste associated with cured meat is also affected by the addition of sodium nitrite.<ref name="Sindelar Human safety" /> However, the mechanism underlying this change in taste is still not fully understood.<ref name="Sindelar One" />

==== Inhibition of microbial pathogens ====
In conjunction with salt and pH levels, sodium nitrite reduces the ability of ''[[Clostridium botulinum]]'' spores to grow to the point of producing toxin.<ref name="FSAINitriteInMeat" /><ref>{{cite journal | vauthors = Lee S, Lee H, Kim S, Lee J, Ha J, Choi Y, Oh H, Choi KH, Yoon Y | title = Microbiological safety of processed meat products formulated with low nitrite concentration - A review | journal = Asian-Australasian Journal of Animal Sciences | volume = 31 | issue = 8 | pages = 1073–1077 | date = August 2018 | pmid = 29531192 | pmc = 6043430 | doi = 10.5713/ajas.17.0675 }}</ref> Some dry-cured meat products are manufactured without nitrites. For example, [[Parma ham]], which has been produced without nitrite since 1993, was reported in 2018 to have caused no cases of botulism. This is because the interior of the muscle is sterile and the surface is exposed to oxygen.<ref name=Wilson/> Other manufacture processes do not assure these conditions, and reduction of nitrite results in toxin production.<ref>{{cite journal | vauthors = Lebrun S, Van Nieuwenhuysen T, Crèvecoeur S, Vanleyssem R, Thimister J, Denayer S, Jeuge S, Daube G, Clinquart A, Fremaux B | title = Influence of reduced levels or suppression of sodium nitrite on the outgrowth and toxinogenesis of psychrotrophic Clostridium botulinum Group II type B in cooked ham | journal = International Journal of Food Microbiology | volume = 334 | pages = 108853 | date = December 2020 | pmid = 32932195 | doi = 10.1016/j.ijfoodmicro.2020.108853 }}</ref>

Sodium nitrite has shown varying degrees of effectiveness for controlling growth of other spoilage or disease causing microorganisms.<ref name="Sindelar Human safety" /> Although the inhibitory mechanisms are not well known, its effectiveness depends on several factors including residual nitrite level, [[pH]], salt concentration, reductants present and [[iron]] content.<ref name="Sindelar One">{{cite journal |vauthors=Sindelar J, Milkowski A |date=November 2011 |title=Sodium Nitrite in Processed Meat and Poultry Meats: A Review of Curing and Examining the Risk/Benefit of Its Use |url=http://www.meatscience.org/docs/default-source/publications-resources/white-papers/2011-11-amsa-nitrite-white-paper.pdf?sfvrsn=8 |journal=American Meat Science Association |volume=3 |pages=1–14}}</ref> The type of [[bacteria]] also affects sodium nitrite's effectiveness.<ref name="Sindelar One"/> It is generally agreed that sodium nitrite is not effective for controlling [[Gram-negative]] enteric pathogens such as ''[[Salmonella]]'' and ''[[Escherichia coli]]''.<ref name="Sindelar One" />

Other food additives (such as [[Lactic acid|lactate]] and [[sorbate]]) provide similar protection against bacteria, but do not provide the desired pink color.<ref>{{cite journal | vauthors = Seward RA, Deibel RH, Lindsay RC | title = Effects of potassium sorbate and other antibotulinal agents on germination and outgrowth of Clostridium botulinum type E spores in microcultures | journal = Applied and Environmental Microbiology | volume = 44 | issue = 5 | pages = 1212–1221 | date = November 1982 | pmid = 6758699 | pmc = 242170 | doi = 10.1128/AEM.44.5.1212-1221.1982 | bibcode = 1982ApEnM..44.1212S}}</ref><ref>{{cite journal | vauthors = Sofos JN, Busta FF, Bhothipaksa K, Allen CE, Robach MC, Paquette MW |title=Effects of various concentrations of sodium nitrite and potassium sorbate on Clostridium botulinum toxin production in commercially prepared bacon |journal=Journal of Food Science |date=September 1980 |volume=45 |issue=5 |pages=1285–1292 |doi=10.1111/j.1365-2621.1980.tb06539.x}}</ref><ref>{{cite journal | vauthors = Linton M, Connolly M, Houston L, Patterson MF |title=The control of Clostridium botulinum during extended storage of pressure-treated, cooked chicken |journal=Food Control |date=March 2014 |volume=37 |pages=104–108 |doi=10.1016/j.foodcont.2013.09.042}}</ref><ref>{{cite journal | vauthors = Alnoman M, Udompijitkul P, Paredes-Sabja D, Sarker MR | title = The inhibitory effects of sorbate and benzoate against Clostridium perfringens type A isolates | journal = Food Microbiology | volume = 48 | pages = 89–98 | date = June 2015 | pmid = 25790996 | doi = 10.1016/j.fm.2014.12.007 }}</ref>

==== Inhibition of lipid peroxidation ====
Sodium nitrite is also able to effectively delay the development of oxidative [[rancidity]].<ref name="Sindelar One" /> [[Lipid peroxidation]] is considered to be a major reason for the deterioration of quality of meat products (rancidity and unappetizing flavors).<ref name="Sindelar One" /> Sodium nitrite acts as an [[antioxidant]] in a mechanism similar to the one responsible for the coloring effect.<ref name="Sindelar One" /> Nitrite reacts with [[heme]] proteins and metal ions, neutralizing [[free radicals]] by [[nitric oxide]] (one of its byproducts).<ref name="Sindelar One" /> Neutralization of these free radicals terminates the cycle of [[lipid oxidation]] that leads to rancidity.<ref name="Sindelar One" />