18.07.2014

Parisi et al (2015) Food Control 47:161-165

The study was conducted to determine microbiological contamination of free-range and conventional chicken eggs produced under controlled conditions. Prevalence of Salmonella and Campylobacter were determined on crushed egg shells and in feces collected from hens at 24 and 28 weeks of age. Counts of total aerobic microorganisms recovered from Battery cages (BC) and Free-Range (FR) eggs ranged from 5.0 to 6.0 log10 CFU/mL. Numbers of Enterobacteriaceae averaged 1.0 log CFU/mL higher (90% greater) on FR eggs than on eggs from BC hens. Salmonella was not detected on any of the eggs collected from BC hens, but prevalence on eggs collected from FR hens was 2.36% positive. Prevalence of Campylobacter recovered from eggs collected from FR (26.1% positive) was significantly higher than the prevalence of Campylobacter recovered from eggs from BC hens (7.4% positive). These data demonstrate that FR eggs, where hens have more contact with eggs after oviposition, have greater microbiological contamination on the egg shell surface than eggs produced in the BC cage systems.