Freezer burn

{{Short description|Damage in frozen food}}

{{Other uses|Freezer Burn (disambiguation){{!}}Freezer Burn}}

Image:FreezerBurn.jpg

Freezer burn is a condition that occurs when frozen food has been damaged by dehydration and oxidation due to air reaching the food.{{cite news |url=https://www.loc.gov/rr/scitech/mysteries/freezerburn.html |title=What is 'freezer burn?' |work=Everyday Mysteries: Fun Science Facts from the Library of Congress |author=Library of Congress |url-status=live |archiveurl=https://web.archive.org/web/20070901055214/http://www.loc.gov/rr/scitech/mysteries/freezerburn.html |archivedate=2007-09-01}} It is generally caused by food not being securely wrapped in air-tight packaging.

Freezer burn appears as grayish-brown leathery spots on frozen food and occurs when air reaches the food's surface and dries the product. Color changes result from chemical changes in the food's pigment. Freezer burn does not make the food unsafe; it merely causes dry spots in foods.{{cite web |website=USFDA |url=http://www.cfsan.fda.gov/~dms/qa-sto3.html |title=Does 'freezer burn' make food unsafe? |url-status=dead |archiveurl=https://web.archive.org/web/20080617154817/http://www.cfsan.fda.gov/~dms/qa-sto3.html |archivedate=June 17, 2008 }} The food remains usable and edible, but removing the freezer burns will improve the flavor.

The dehydration of freezer-burned food is caused by water sublimating from the food into the surrounding atmosphere. The lost water may then be deposited elsewhere in the food and packaging as snow-like crystals.{{Cite book |last=Heiss |first=Rudolf |title=Haltbarmachen von Lebensmitteln : chemische, physikalische und mikrobiologische Grundlagen der Verfahren |date=1990 |publisher=Springer |others=K. Eichner |isbn=978-3-662-07666-8 |edition=2nd, neubearbeitete und erw. Aufl |location=Berlin |oclc=689919077}}{{Cite book |last=Buchner |first=Norbert |title=Verpackung von Lebensmitteln : Lebensmitteltechnologische, verpackungstechnische und mikrobiologische Grundlagen |date=1999 |isbn=978-3-642-58585-2 |location=Berlin; Heidelberg |publisher=Springer Berlin Heidelberg |oclc=913722328}} Fluctuation of temperatures in a freezer, such that the temperature does not remain consistently below -18°C, can also speed up freezer burn.{{cite news |url=https://www.loc.gov/rr/scitech/mysteries/freezerburn.html |title=What is 'freezer burn?' |work=Everyday Mysteries: Fun Science Facts from the Library of Congress |publisher=Library of Congress |url-status=live |archiveurl=https://web.archive.org/web/20070901055214/http://www.loc.gov/rr/scitech/mysteries/freezerburn.html |archivedate=2007-09-01}}