不同保存方式对新鲜母乳中免疫活性因子、细菌菌落及营养成分的影响

Effects of different preservation methods on immune activity factors,bacterial colonies and nutrients in fresh breast milk

目的探讨不同保存方式对新鲜母乳中免疫活性因子、细菌菌落及营养成分的影响。方法采集2018年10月至2020年10月在我院分娩后的86例产妇产后42d的新鲜母乳140 mL,分为7份,每份20 mL,1份新鲜母乳,其余6份分别储放于聚乙烯储奶瓶中。将储奶瓶分别存放至4℃、-18℃和-20℃的冰箱中(每个温度条件各2份)。于4℃保存48 h、72 h,-18℃和-20℃中存放30 d和90 d后检测储放母乳的免疫活性因子[白介细胞素-6(IL-6),乳铁蛋白(LF),肿瘤坏死因子(TNF-α)]、细菌菌落水平及营养成分(脂肪、蛋白质、碳水化合物),并与新鲜母乳比较。结果与新鲜母乳比较,在各设定条件下的LF水平、细菌菌落计数比较无明显差异(P>0.05);IL-6水平在各设定条件下随着时间的推移逐渐下降(P<0.05),TNF-α水平在4℃的条件下保存72 h下降,在-18℃与-20℃的条件下保存30 d、90 d均上升(P<0.05);各营养物质在4℃的保存条件下仅脂肪水平在72 h后下降明显(P<0.05),其余物质水平无明显差异(P<0.05)。在-18℃与-20℃的条件下各营养物质下降趋势明显(P<0.05)。结论在低温环境下保存母乳对免疫活性因子和营养物质有一定的影响,建议在4℃的保存条件下保存时长不应超过72 h,在-18℃与-20℃的保存条件下保存时长不应超过90 d。

Objective To explore the effects of different preservation methods on immune activity factors,bacterial colonies and nutrients in fresh breast milk.Methods A total of 140ml of fresh breast milk at 42 d after delivery was collected from 86 puerperae in the hospital between October 2018 and October 2020.It was divided into seven,20 mL in each.One of them was fresh breast milk,and the remaining six were stored in polyethylene milk bottles.The bottles were placed in refrigerators at 4°C,-18°C and-20°C(every two pieces of milk in each temperature condition),respectively.The milk samples at 4°C were stored for 48 h and 72 h,milk samples at-18°C were stored for 30d and those at-20°C were stored for 90d.After that,levels of immune activity factors[interleukin-6(IL-6)、lactoferrin(LF)、tumor necrosis factorα(TNF-α)]、bacterial colonies and nutrients(fat,protein,carbohydrate)in breast milk were detected,and which were compareed with those in fresh breast milk.Results Compared with fresh breast milk,difference in LF level and counts of bacterial colonies in breast milk under each setting conditions was not statistically significant(P>0.05).IL-6 level was gradually decreased over time under each setting condition(P<0.05).The level of TNF-αwas decreased when stored at 4℃for 72 h,while which was increased at-18℃and-20℃for 30 d and 90 d(P<0.05).In all nutrients,only level of fat was significantly decreased when stored at 4℃for 72 h(P<0.05),but there was no significant difference in the levels of the other nutrients(P<0.05).At-18°C and-20°C,downward trends of each nutrient were significant(P<0.05).Conclusion There are certain effects of storing breast milk in low temperature environment on immune activity factors and nutrients.It is recommended that the storage time should not longer than 72 h at 4℃,and not longer than 90 d at-18℃and-20℃.