Hutchings Carmel, Prokocimer Yair Zafnat, Reifen Ram, Shemesh Moshe
Department of Food Sciences, Institute for Postharvest Technology and Food Sciences, Agricultural Research Organization (ARO), Volcani Center, Rishon LeZion 7528809, Israel.
School of Nutrition Science, Institute of Biochemistry, Food Science and Nutrition, The Robert H. Smith Faculty of Agriculture, Food and Environment, Institute of Biochemistry, Food Science and Nutrition, The Hebrew University of Jerusalem, Rehovot 761001, Israel.
Foods. 2021 Mar 17;10(3):637. doi: 10.3390/foods10030637.
Donor human milk (HM) obtained at HM banks is exceptionally crucial for the feeding and treatment of preterm infants. Bacterial contaminations of HM in various stages of its handling are very common and can lead to disqualification of donations or severe infections in worse cases. Hence, HM donations are subject to strict bacteriological evaluations pre- and post-pasteurization. The main contaminating species vary between countries, banks and donors and even exhibit inter-individual variation. We initiated an assessment of the bacteriological composition of HM donated by women hospitalized in a neonatal intensive care unit in Israel. The most common bacterium identified was , found in all but one of the HM samples; the presence of several species of coagulase-negative was also noted. Next, we sought to develop a platform towards antibacterial treatment using Zn ions that have recently been found to be potent against contaminants isolated from bovine milk. Zn efficiently inhibited the growth of viable aerobic population and in HM. Growth was also inhibited in other Gram-positive bacteria such as , a well-known food-borne pathogen. and cells grown in the presence of zinc were taken for microscopic evaluation, aiming to demonstrate zinc's antimicrobial mode of action morphologically. Images obtained using scanning electron microscopy indicated leakage of cellular content and cell lysis in . Besides, cells showed abnormalities in their cell surface and complete loss of flagella upon treatment with zinc. Along with the above findings, it should be noted that this was a pilot study that tested how high doses of Zn affect breast milk as a product. Further research is likely needed on the safety of consumption of Zn-treated HM in infants and older children.
母乳库提供的捐赠人乳对早产儿的喂养和治疗极为关键。人乳在处理的各个阶段受到细菌污染的情况非常普遍，在最坏的情况下可能导致捐赠不合格或引发严重感染。因此，人乳捐赠在巴氏杀菌前后都要接受严格的细菌学评估。主要污染菌种因国家、母乳库和捐赠者而异，甚至存在个体差异。我们对以色列一家新生儿重症监护病房住院女性捐赠的人乳进行了细菌学组成评估。鉴定出的最常见细菌是 ，除了一个人乳样本外，在所有样本中都有发现；还注意到几种凝固酶阴性菌的存在。接下来，我们试图开发一个使用锌离子进行抗菌治疗的平台，最近发现锌离子对从牛乳中分离出的污染物有很强的抗菌作用。锌能有效抑制人乳中需氧活菌和 的生长。其他革兰氏阳性菌如 （一种著名的食源性病原体）的生长也受到抑制。对在锌存在下生长的 和 细胞进行显微镜评估，旨在从形态学上证明锌的抗菌作用模式。使用扫描电子显微镜获得的图像显示 细胞内容物泄漏和细胞裂解。此外， 细胞在用锌处理后细胞表面出现异常，鞭毛完全消失。除上述发现外，应注意这是一项初步研究，测试了高剂量锌作为一种产品对母乳的影响。可能需要对婴儿和大龄儿童食用经锌处理的人乳的安全性进行进一步研究。
