Selenium in Japanese baby foods.

The selenium content of various baby foods was determined by spectrofluorimetry. Mean levels of Se (ng ml-1) decreased in the sequence: pasteurized cow's milk (28.4) greater than raw cow's milk (23.1) greater than mature human milk (22.5) greater than milk-based infant formulae (6.6). The sequence of mean values of Se (ng mg-1 protein) was: human milk (1.57) greater than raw cow's milk (0.96) greater than infant formulae (0.37). Dietary Se intake (microgram day-1) of 3 month old infants fed on infant formula and various milks decreased in the order: human milk (21.0) greater than pasteurized cow's milk (18.9) greater than raw cow's milk (15.0) greater than infant formulae (5.4). There was a significant positive correlation (r = 1.00, p less than 0.001) between the Se content of the infant formula product and that of the pasteurized milk product of three manufacturers. Hot air treatment reduced the Se content of cow's milk with increasing temperature and time of heating: loss of Se amounted to 11.1% at 210 degrees C for 25 min. The Se content of human milk was positively correlated (r = 0.64, p less than 0.001) with its protein content and negatively correlated (r = -0.77, p less than 0.01) with its fat content. These correlations were not found for infant formulae.