MICROBIOLOGICAL COMPARISON OF TABLE EGGS HARVESTED FROM CAGED LEGHORN HENS AND CAGE-FREE FLOOR REARED LEGHORN HENS
Location: Poultry Microbiological Safety Research
Title: Room environment influence on eggshell bacterial levels of non-washed and washed eggs from caged and cage-free laying hens
Submitted to: Poultry Science Association Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: March 31, 2009
Publication Date: July 21, 2009
Citation: Buhr, R.J., Hannah, J.F., Wilson, J.L., Cox Jr, N.A., Richardson, L.J., Cason Jr, J.A., Musgrove, M.T. 2009. Room environment influence on eggshell bacterial levels of non-washed and washed eggs from caged and cage-free laying hens. Poultry Science Association Meeting Abstract. 88(Suppl.1):228. P. 72.
The bacteria levels of non-washed and washed eggs obtained from caged and cage-free hens housed in either wire slats or shaving-covered pens were determined. On eight days (from 22 to 52 wk), 20 eggs were collected from each pen. Ten eggs/pen were washed with a commercial egg washing solution, while the remaining 10 eggs were not washed prior to sampling the eggshell and membranes for aerobic bacteria (APC), Escherichia coli (E. coli), and coliforms. Non-washed eggs produced in an all shavings environment had slightly higher bacteria numbers (APC 4.0 and coliforms 1.1 log10 cfu/mL of rinsate) than eggs produced on slats (APC 3.6 and coliforms 1.06 log10 cfu/mL), which had significantly higher bacteria numbers than eggs produced in cages (APC 3.1 and coliforms 0.88 log10 cfu/mL). Washing significantly reduced APC counts by 1.7 log10 cfu/mL, and APC prevalence was reduced from 100, 99, and 98% (shavings, slats, and cages, respectively) to 87% for shavings and to 68% for caged and slat hens. Washing significantly reduced coliform counts by 0.5 log10 cfu/mL and prevalence was reduced from 22.5, 17.5, 12.5% (shavings, slats, and cages, respectively) to 6%. No significant differences were found in APC, E. coli, and coliform counts on eggs from the three housing types after the egg were washed. At 53 wk hens were moved to triple-deck cages in an all cage room. From 57 to 62 wk, eggs were collected weekly and both non-washed and washed eggs were sampled for only APC. Non-washed eggs produced by hens in cages (previously housed on shavings, slats, and cages) did not differ with APC counts from 0.67 to 0.84 log10 cfu/mL. Washing eggs continued to significantly reduce APC counts to below 0.2 log10 cfu/mL. APC prevalence for eggs from the triple-deck caged hens after washing was 37% compared to 74% when hens were housed on shavings, slats, or cages. Housing hens in cages with manure removal belts resulted in lower APC for both non-washed and washed eggs (compared to eggs from hens housed in a room with cages, slats, and shavings) and corresponding reductions in human pathogens would further improve food safety.