Microflora on egg shells from different housing systems

The bacteriological status of hen's eggshells was examined with respect to caging and free-range housing systems. An analysis of variance ([lg] cfu/cm(2) eggshell) using "housing system" and "quality of eggshell" as factors of influence was performed. The number of cfu of free-range eggs (3.20-4.30 [Ig] cfu/cm(2)) was about 10(1) cfu/cm(2) higher than the number of cfu of cage eggs (2.30-3.90[Ig] cfu/cm(2), p less than or equal to 0.001). Altogether, more bacteria on dirty eggshells than on clean eggshells were found (P less than or equal to 0.036). There was a great conformity in the taxonomy of bacteria. The percentage of Micrococcaceae was higher on free-range eggs than on cage eggs, whereas the percentage of gramnegative bacteria and of irregular non-sporing rods was higher on cage eggs.