Editing Slaughterhouse (section)

==Preservation techniques==
Refrigeration technology allowed meat from the slaughterhouse to be preserved for longer periods. This led to the concept of the slaughterhouse as a freezing works. Prior to this, canning was an option.<ref>{{cite web|url=http://www.techhistory.co.nz/19thcentury/Meat.htm|title=The 19th Century Heritage: the meat industry|website=www.techhistory.co.nz|access-date=8 January 2019}}</ref> Freezing works are common in New Zealand, Australia and South Africa. In countries where meat is exported for a substantial profit the freezing works were built near docks, or near transport infrastructure.<ref>{{cite web|url=https://teara.govt.nz/en/98181|title=7. Agricultural processing industries – Te Ara Encyclopedia of New Zealand|first=New Zealand Ministry for Culture and Heritage Te Manatu|last=Taonga|website=teara.govt.nz|access-date=8 January 2019}}</ref>

Mobile poultry processing units (MPPUs) follow the same principles, but typically require only one trailer and, in much of the United States, may legally operate under USDA exemptions not available to red meat processors.<ref>{{cite web|url=https://www.sare.org/Learning-Center/SARE-Project-Products/Northeast-SARE-Project-Products/Building-an-On-Farm-Poultry-Processing-Facility|title=Building an On-Farm Poultry Processing Facility|website=www.sare.org|access-date=6 June 2020}}</ref> Several MPPUs have been in operation since before 2010, under various models of operation and ownership.<ref>{{cite web|url=https://www.nichemeatprocessing.org/mobile-poultry-processing-units-reports-from-the-field/|title=Mobile Poultry Processing Units: Reports From the Field|website=www.www.nichemeatprocessing.org|access-date=6 June 2020}}</ref>