Water activity of poultry litter: Relationship to moisture content during a grow-out. (1st May 2016)

• Record Type: Journal Article
• Authors: Dunlop, Mark W.; McAuley, Jim; Blackall, Patrick J.; Stuetz, Richard M.
• Is Part Of: Journal of environmental management. Volume 172(2016)
• Page Start: 201
• Page End: 206
• Publication Date: 2016-05-01
• Subjects: Broiler -- Meat chicken -- Equilibrium relative humidity (ERH) -- Wet litter -- Water absorption isotherms; Environmental policy -- Periodicals; Environmental management -- Periodicals; Environment -- Periodicals; Ecology -- Periodicals; 363.705
• DOI: 10.1016/j.jenvman.2016.02.036
• Languages: English
• ISSNs: 0301-4797

Abstract

Abstract: Poultry grown on litter floors are in contact with their own waste products. The waste material needs to be carefully managed to reduce food safety risks and to provide conditions that are comfortable and safe for the birds. Water activity (Aw ) is an important thermodynamic property that has been shown to be more closely related to microbial, chemical and physical properties of natural products than moisture content. In poultry litter, Aw is relevant for understanding microbial activity; litter handling and rheological properties; and relationships between in-shed relative humidity and litter moisture content. We measured the Aw of poultry litter collected throughout a meat chicken grow-out (from fresh pine shavings bedding material to day 52) and over a range of litter moisture content (10–60%). The Aw increased non-linearly from 0.71 to 1.0, and reached a value of 0.95 when litter moisture content was only 22–33%. Accumulation of manure during the grow-out reduced Aw for the same moisture content. These results are relevant for making decisions regarding litter re-use in multiple grow-outs as well as setting targets for litter moisture content to minimise odour, microbial risks and to ensure necessary litter physical conditions are maintained during a grow-out. Methods to predict Aw in poultry litter from moisture content are proposed. Graphical abstract: Highlights: Water activity was measured in meat chicken (broiler) litter during a grow-out. Reducing litter water activity is known to reduce ​friability and microbiota growth. Water activity reduced as litter aged and manure accumulated during a grow-out. Fresh bedding materials had high water activity and thus support microbiota growth. Methods to predict water activity from moisture content are proposed.