As part of a more comprehensive study on the use of modified-atmosphere packaging for the improvement of quality and functional properties of table eggs, the effects of air, 100 per cent carbon dioxide, and 100 per cent oxygen packaging were also evaluated on the survival of experimentally inoculated pathogen bacteria (Salmonella Enteritidis, Escherichia coli, and Listeria monocytogenes) as well as on spoilage bacteria (total aerobic mesophilic bacteria) on table eggs during 30 days of storage at 4, 25 and 37°C using the colony count method.

Reporting this part of the study in the current issue of Poultry Science, Frederique Pasquali and colleagues at the University of Bologna observed that in general, temperature played a more important role than the gases in influencing the bacterial survival. In particular, the lowest microbial loads were registered at 4°C on E.coli and spoilage bacteria, whereas 37°C was the best storage temperature to avoid the psychrotropic microorganism L. monocytogenes development, regardless of the gas used.

One hundred per cent carbon dioxide packaging, in association with a low storage temperature (4°C), had a significant positive effect in reducing Salmonella loads. On eggs inoculated with L. monocytogenes and stored at 4°C as well as on eggs containing only spoilage bacteria and stored at 25°C, 100 per cent carbon dioxide resulted the best gas in comparison with air and oxygen.

One hundred per cent carbon dioxide packaging showed no negative effect on pathogen survival compared with air.

Although further improvements are required to control relative humidity within packaging to limit bacteria growth/survival, in view of the positive effects of carbon dioxide packaging on quality traits of table eggs, 100 per cent carbon dioxide packaging might represent a promising innovative technique for the maintenance of egg characteristics during transport, retail and domestic storage, concluded Pasquali and colleagues.

Reference

Pasquali F., G. Manfreda, P. Olivi, P. Rocculi, F. Sirri and A. Meluzzi. 2012. Modified-atmosphere packaging of hen table eggs: Effects on pathogen and spoilage bacteria. Poult. Sci., 91(12):3253-3259. doi: 10.3382/ps.2012-02655

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