背景:捐献者母乳银行使用Holder巴氏灭菌法(62.5ºC,30分钟)以减少供体人乳中的病原体,但是这个过程会损害一些生物活性乳蛋白。
目的:我们旨在确定高压处理(HPP)的最小参数,以实现>5-log的人乳中相关细菌的减少,以及这些参数如何影响一系列生物活性蛋白。
方法:接种相关病原体(屎肠球菌,金黄色葡萄球菌,单核细胞增生李斯特菌,SakazakiiCronobacter)或微生物质量指标(枯草芽孢杆菌和半芽孢杆菌属。7logCFU/mL的孢子)在300-500MPa下在16-19°C(由于绝热加热)下处理1-9分钟。使用标准平板计数方法对存活微生物进行计数。对于原始的,HPP处理和Holder巴氏灭菌(HoP)处理的牛奶,通过ELISA评估一系列生物活性蛋白的免疫反应性,通过比色底物测定法测定胆盐刺激脂肪酶(BSSL)的活性.
结果:在500MPa下处理9分钟导致所有营养细菌减少>5-log,但枯草芽孢杆菌和芽孢杆菌<1-log减少。HOP降低免疫球蛋白A(IgA),IgM,IgG,乳铁蛋白,弹性蛋白酶和聚合免疫球蛋白受体(PIGR)浓度和BSSL活性。在500MPa下处理9分钟保留了更多的IgA,IgM,弹性蛋白酶,乳铁蛋白,PIGR和BSSL比HoP。高达500MPa的HoP和HPP治疗9分钟不会导致骨桥蛋白的损失,溶菌酶,α-乳白蛋白和血管内皮生长因子。
结论:与HoP相比,HPP在500MPa下持续9分钟可使测试的营养新生儿病原体减少>5-log,并改善IgA的保留,IgM,乳铁蛋白,弹性蛋白酶,PIGR,和人乳中的BSSL。
Donor human milk banks use Holder pasteurization (HoP; 62.5°C, 30 min) to reduce pathogens in donor human milk, but this process damages some bioactive milk proteins.
We aimed to determine minimal parameters for high-pressure processing (HPP) to achieve >5-log reductions of relevant bacteria in human milk and how these parameters affect an array of bioactive proteins.
Pooled raw human milk inoculated with relevant pathogens (Enterococcus faecium, Staphylococcus aureus, Listeria monocytogenes, Cronobacter sakazakii) or microbial quality indicators (Bacillus subtilis and Paenibacillus spp. spores) at 7 log CFU/mL was processed at 300-500 MPa at 16-19°C (due to adiabatic heating) for 1-9 min. Surviving microbes were enumerated using standard plate counting methods. For raw milk, and HPP-treated and HoP-treated milk, the immunoreactivity of an array of bioactive proteins was assessed via ELISA and the activity of bile salt-stimulated lipase (BSSL) was determined via a colorimetric substrate assay.
Treatment at 500 MPa for 9 min resulted in >5-log reductions of all vegetative bacteria, but <1-log reduction in B. subtilis and Paenibacillus spores. HoP decreased immunoglobulin A (IgA), immunoglobulin M (IgM), immunoglobulin G, lactoferrin, elastase and polymeric immunoglobulin receptor (PIGR) concentrations, and BSSL activity. The treatment at 500 MPa for 9 min preserved more IgA, IgM, elastase, lactoferrin, PIGR, and BSSL than HoP. HoP and HPP treatments up to 500 MPa for 9 min caused no losses in osteopontin, lysozyme, α-lactalbumin and vascular endothelial growth factor.
Compared with HoP, HPP at 500 MPa for 9 min provides >5-log reduction of tested vegetative neonatal pathogens with improved retention of IgA, IgM, lactoferrin, elastase, PIGR, and BSSL in human milk.