New short-term heat inactivation method of cytomegalovirus (CMV) in breast milk: impact on CMV inactivation, CMV antibodies and enzyme activities

Objectives Breast milk (BM) is the primary source of cytomegalovirus (CMV) transmission to premature infants with potentially harmful consequences. We therefore wanted to evaluate temperature and duration of short-term BM pasteurisation with respect to CMV inactivation, effect on CMV-IgG antibodies and BM enzyme activities. Methods 116 artificially CMV-spiked BM and 15 wild-type virus-infected samples were subjected for 5 s to different temperatures (55 degrees C-72 degrees C). CMV-IE-1 expression in fibroblast nuclei was assessed using the milk whey fraction in short-term microculture. BM lipase and alkaline phosphatase (AP) activities and CMV binding using CMV-recomLine immunoblotting and neutralising antibodies using epithelial target cells were analysed before and after heating. Results A minimum of 5 s above 60 degrees C was necessary for CMV inactivation in both CMV-AD-169 spiked and wild-type infected BM. Lipase was very heat sensitive (activities of 54% at 55 degrees C, 5% at 60 degrees C and 2% at 65 degrees C). AP showed activities of 77%, 88% and 10%, respectively. CMV-p150 IgG antibodies were mostly preserved at 62 degrees C for 5 s. Conclusion Our results show that short-term pasteurisation of BM at 62 degrees C for 5 s might be efficient for CMV inactivation and reduces loss of enzyme activities, as well as CMV binding, and functional CMV antibodies.