05.Choice egg freshness testing
Eggs are a perishable commodity. The Australian Egg Corporation’s Code of Practice recommends that eggs should be transported and stored at below 15°C — including in retail outlets. Nonetheless, most supermarkets have them out on aisle shelves, rather than in refrigerators.
We tested more than 650 eggs (all production systems), using an internationally recognised measure of egg freshness and quality called a Haugh unit (see How we tested, below).
There are no prescribed Australian standards but the US standard classifies eggs under 60 Haugh units as ‘weak and watery’ and we used this as our benchmark for freshness.
Of all the eggs we tested, 36 percent had Haugh units below 60 (see table for details). This is an improvement on our last test, in 2004, but may reflect cooler weather rather than improved handling. A similar survey to ours done in the summer months found a failure rate of 77 percent (The Sun-Herald, March 2, 2008).
The Australian Egg Corporation told us that its research shows that eggs deteriorate in one day on the shelves as much as they would in seven days in the fridge. But only one supermarket where we bought eggs (a Woolworths store in Sydney) had them refrigerated.
We found no significant difference overall between the freshness and quality of the eggs from the two big supermarket chains. And on average we found no significant differences between the freshness of barn-laid, cage and free-range eggs.
In the table we’ve ranked the brands by their fail rate. Seven achieved the top score of zero failures:
- Boost Vegetarian Cage (Brisbane)
- Essential Foods Free-Range (Melbourne)
- Family Homestead Free-Range (Melbourne)
- Field Fresh Free-Range (Sydney)
- Golden Eggs Barn-Laid (Perth)
- Nature's Best Free-Range (Sydney)
- Sunny Queen Farms Barn-Laid (Brisbane)
- Only one brand, Farm Pride Barn-Laid, failed 100 percent.
How we tested
We bought free-range, barn and cage eggs of each brand that we found in a Coles and Woolworths supermarket in Brisbane, Melbourne, Perth and Sydney. Where possible, we chose 700g boxes and looked for the longest time before the best-before date.
Our tester randomly selected five eggs from each box and cracked them open, one at a time, onto a flat glass surface and, using a micrometer, measured the height of the white. A Haugh unit is an internationally recognised measure of egg freshness and is based on a mathematical formula that combines the weight of the egg and the thickness of the white.