Rapid growth of Salmonella enteritidis in egg white reconstituted from industrial egg white powder

The aim of this study was to evaluate the consequences of the egg white-dry ing process on egg white ability to limit Salmonella Enteritidis growth in addition to the elucidation of the factors involved. We observed rapid grow th of Salmonella Enteritidis inoculated in egg white reconstituted from ind ustrial powder in comparison with that observed in liquid egg white collect ed in the laboratory: Salmonella cell counts rose from 10(3) to 10(8) cells /ml of egg white from powder during 24 h incubation at 30 degrees C. This r apid growth was observed in powder from all egg-breaking factories investig ated, and it was comparable to that observed in optimum medium (tryptone so y broth). In view of the mechanism of egg white resistance and the major ro le played by iron availability and by ovotransferrin, we investigated sever al hypotheses to explain this rapid growth: iron provided during the drying process and/or denaturation of protein (especially ovotransferrin). The ra pid growth observed in egg white reconstituted from powder was in relation to egg white protein denaturation and especially ovotransferrin denaturatio n during powder pasteurization that enhanced the availability of iron neces sary for Salmonella growth. The major role played by ovotransferrin and iro n deficiency on Salmonella growth in egg white was illustrated in this stud y.