Effect Of Cold Storage On The Nutrient And Immune Substance Of Human Milk

Objective: To explore the optimal storage standard of fresh human milk, this study observed the influence of different cold storage condition(time-temperature) on macronutrients(fat, protein, carbohydrates, TS, and energy), immune substance(s Ig A, lactoferrin, IL-6, IL-8, IL-10, and TNF-?) and bacteria indicators of fresh human milk.Methods: Fresh milk samples(n=30) were divided and stored for there temperature and nine time point, which are 24h(4?), 48h(4?), 72h(4?), 72h(-18?), 7d(-18?), 14d(-18?), 4W(-18?), 8W(-18?), 12W(-18?), 12W(-80?), and 24W(-80?). At each time point, the macronutrients(fat, protein, carbohydrates, TS, and energy), immune substance(s Ig A, lactoferrin, IL-6, IL-8, IL-10, and TNF-?) and bacteria colony counts of each milk sample were measured and compared with fresh milk.Results: Compared with fresh milk, the concentrarion of macronutrients(fat, protein, carbohydrates, TS, and energy), immune substance(s Ig A, IL-6, IL-8, IL-10, and TNF-?) and bacteria indicators of stored human milk had significant difference(P<0.05). Under 4? refrigeration condition, the concentrarion of fat, IL-6 and TNF-? decreased, bacteria colony counts and Gram-positive colony counts increased over 72 h storage(P<0.05). Under-18? freezing condition, the concentration of fat, protein, TS, energy and IL-6 decreased from 72 h to 12 W storage(P<0.05); the level of carbohydrates and s Ig A also decreased from 4W to 12 W storage and from 8W to 12 W storage, respectively(both P<0.05). Under-80? freezing condition,the concentration of fat, protein, TS, energy and IL-6 decreased over 24 W storage(P<0.05).Conclusion: The macronutrients, immune substance and bacteria indicators of human milk were influenced obviously by cold storage. As the decline of fat concentration and increase of bacteria colony counts during 4? storage, refrigerated at 4? should be not longer than 72 h, otherwise-18? storage should be taken. And because the loss of macronutrients and main immune protein s Ig A,-80? deep freezing should be chosen for more than 8 weeks.