Comparison of shell bacteria from unwashed and washed table eggs harvested from caged laying hens and cage-free floor-housed laying hens

Abstract

These studies evaluated the bacterial level of unwashed and washed shell eggs from caged and cage-free laying hens. Hy-Line W-36 White and Hy-Line Brown laying hens were housed on all wire slats or all shavings floor systems. On the sampling days for experiments 1, 2, and 3, 20 eggs were collected from each pen for bacterial analyses. Ten of the eggs collected from each pen were washed for 1 min with a commercial egg-washing solution, whereas the remaining 10 eggs were unwashed before sampling the eggshell and shell membranes for aerobic bacteria and coliforms (experiment 1 only). In experiment 1, the aerobic plate counts (APC) of unwashed eggs produced in the shavings, slats, and caged-housing systems were 4.0, 3.6, and 3.1 log(10) cfu/mL of rinsate, respectively. Washing eggs significantly (P < 0.05) reduced APC by 1.6 log(10) cfu/mL and reduced the prevalence of coliforms by 12%. In experiment 2, unwashed eggs produced by hens in triple-deck cages from 57 to 62 wk (previously housed on shavings, slats, and cages) did not differ, with APC ranging from 0.6 to 0.8 log(10) cfu/mL. Washing eggs continued to significantly reduce APC to below 0.2 log(10) cfu/mL. In experiment 3, the APC for unwashed eggs were within 0.4 log below the APC attained for unwashed eggs in experiment 1, although hen density was 28% of that used in experiment 1. Washing eggs further lowered the APC to 0.4 to 0.7 log(10) cfu/mL, a 2.7-log reduction. These results indicate that shell bacterial levels are similar after washing for eggs from hens housed in these caged and cage-free environments. However, housing hens in cages with manure removal belts resulted in lower APC for both unwashed and washed eggs (compared with eggs from hens housed in a room with shavings, slats, and cages).

New technologies to enhance quality and safety of table eggs: ultra-violet treatment and modified atmosphere packaging

“…The load of naturally occurring bacteria was low both for total and faecal coliforms confirming previously reported studies (Hannah et al, 2011). The UV treatment alone was effective in reducing the load of total bacteria on the surface of effectiveness of the UV treatment was reinforced during storage.…”

The effect of neutral electrolyzed water as a disinfectant of eggshells artificially contaminated with Listeria monocytogenes

“…The differences were statistically significant (p < 0.01) for both disinfectants analyzed. Previous works (Hannah et al, 2011;Mansour, Zayed, & Basha, 2015) reported similar titers and (Spitzer, 2015) reported that the main egg structure that is contaminated by bacteria is the eggshell and this contamination depends of the production method. We tried to increase the sensibility of the methodology from 1,000 to 100 CFU/egg by taking samples directly from the washing solutions (no-dilution); however, we could not detect any bacteria in Palcam nor TSA plates (data not shown).…”

Effect of Washing on Selected Quality Traits of Hen Egg Shells During Storage

“…Hannah i wsp. [5] wskazują, że niepoddane myciu skorupy jaj od niosek z chowu klatkowego charakteryzowały się obecnością większej liczby bakterii tlenowych niż jaja z chowu na ściółce z wiórów drzewnych. Po umyciu jaj liczba bakterii na ich skorupie nie była czynnikiem różnicującym systemy chowu.…”