Immunological Evaluation of Pasteurized, Deaerated Human Milk

Retention of immunoglobulin A (IgA) and IgA specific for enteropathogenic Escherichia coli (EPEC) was determined in human milk that was processed and stored under refrigeration or frozen conditions. Human milk was subjected to three different processing conditions: (a) deaerated, vacuum packaged in metalized polyester bags and pasteurized (64°C for 6 min, 10 s); (b) vacuum packaged and pasteurized; (c) vacuum packaged. Samples were stored at 4°C for 7 d and at -20°C for 28 d. An enzyme-linked immunosorbent assay (ELISA) to detect antibodies to EPEC was developed and used to monitor these antibody levels, while radial immunodiffusion (RID) plates were used to provide information on total IgA of the milk samples. In addition, the dissolved oxygen content of the samples was monitored. It was found that pasteurization and deaeration did not adversely affect the IgA levels, and levels of total IgA and IgA specific for EPEC remained stable or increased slightly during storage in most samples regardless of the storage temperatures.