June 16, 2009

A New Zealand researcher has developed a technique to identify the difference between eggs from caged hens and those from free-range and organically-raised hens.

 

Dr Karyne Rogers, of Geological and Nuclear Science's National Isotope Centre in Lower Hutt, New Zealand has used the isotope analysis--believed to be used for the first time--to compare, different brands of off-the-shelf eggs from cage, barn, free range and organic farming regimes.

 

The system may help the egg industry on mislabelling.

 

Using isotope analysis, Rogers found almost all the eggs could be differentiated by relating the carbon and nitrogen found in the egg to the hen's diet.

 

This was possible as diet directly reflected the type of farming environment where the hens were raised, Dr Rogers said.

 

According to Dr Rogers, free-range and organically farmed hens normally have access to a wider range of food sources than caged hens, such as insects, vegetation or organic feeds, and this changes the isotope fingerprint of their eggs.

 

The research, recently published in the Journal of Agricultural and Food Chemistry, was performed on egg yolk, albumen and egg membrane to see which egg components gave the best information about the hen's diet.

 

Dr Rogers said the technique is a promising tool to guard against mislabelling. However, she asked for financial support to fully develop the technique so that "it can be fully tested and applied in the industry."