Editing Food preservation (section)

=== Hurdle technology ===
{{Main|Hurdle technology}}

[[Hurdle technology]] is a method of ensuring that [[pathogen]]s in [[food product]]s can be eliminated or controlled by combining more than one approach. These approaches can be thought of as "hurdles" the pathogen has to overcome if it is to remain active in the food. The right combination of hurdles can ensure all pathogens are eliminated or rendered harmless in the final product.<ref name="Alasalvar" />

Hurdle technology has been defined by Leistner (2000) as an intelligent combination of hurdles that secures the [[microbial]] safety and stability as well as the [[organoleptic]] and nutritional quality and the economic viability of [[food product]]s.<ref>Leistner I (2000) [http://envismadrasuniv.org/Physiology/pdf/Basic%20aspects%20of%20food%20preservation.pdf "Basic aspects of food preservation by hurdle technology"] ''International Journal of Food Microbiology'', '''55''':181–186.</ref> The organoleptic quality of the food refers to its sensory properties, that is its look, taste, smell, and texture.

Examples of hurdles in a food system are high temperature during processing, low temperature during storage, increasing the [[acidity]], lowering the [[water activity]] or [[redox potential]], and the presence of [[preservative]]s or [[biopreservative]]s. According to the type of pathogens and how risky they are, the intensity of the hurdles can be adjusted individually to meet consumer preferences in an economical way, without sacrificing the safety of the product.<ref name="Alasalvar">Alasalvar C (2010) [https://books.google.com/books?id=l-APOWUVp-8C&pg=PT232&dq=%22hurdle+technology%22|%22hurdle+technologies%22&hl=en&ei=5GSFTaTGCJCSuAOj66zGCA&sa=X&oi=book_result&ct=result&resnum=3&ved=0CDgQ6AEwAg#v=onepage&q=%22hurdle%20technology%22|%22hurdle%20technologies%22&f=false ''Seafood Quality, Safety and Health Applications''] John Wiley and Sons, Page 203. {{ISBN|978-1-4051-8070-2}}.</ref>

{| class="wikitable"
|+ Principal hurdles used for food preservation (after Leistner, 1995)<ref>Leistner L (1995) [https://books.google.com/books?id=6a_dbGRoiWIC&q=Principles+and+applications+of+hurdle+technology "Principles and applications of hurdle technology"] In Gould GW (Ed.) ''New Methods of Food Preservation'', Springer, pp. 1–21. {{ISBN|978-0-8342-1341-8}}.</ref><ref name="Lee">Lee S (2004) [http://www.internetjfs.org/articles/ijfsv4-3.pdf "Microbial Safety of Pickled Fruits and Vegetables and Hurdle Technology"] {{Webarchive|url=https://web.archive.org/web/20110901001910/http://www.internetjfs.org/articles/ijfsv4-3.pdf |date=1 September 2011 }} ''Internet Journal of Food Safety'', '''4''': 21–32.</ref>
|-
! Parameter
! Symbol
! Application
|-
| High temperature
| style="text-align:center;"| F
| Heating
|-
| Low temperature
| style="text-align:center;"| T
| [[Refrigeration|Chilling]], [[Frozen food|freezing]]
|-
| Reduced [[water activity]]
| style="text-align:center;"| a{{sub|w}}
| [[Drying]], [[Curing (food preservation)|curing]], [[Conserve (condiment)|conserving]]
|-
| Increased [[acidity]]
| style="text-align:center;"| [[pH]]
| Acid addition or formation
|-
| Reduced [[redox potential]]
| style="text-align:center;"| E{{sub|h}}
| Removal of oxygen or addition of [[ascorbate]]
|-
| [[Biopreservative]]s
|
| Competitive [[flora]] such as [[microbial]] [[Fermentation (food)|fermentation]]
|-
| Other [[preservative]]s
|
| [[Sorbate]]s, [[sulfite]]s, [[nitrite]]s
|}