Sobrino-Lopez A, Viedma-Martínez P, Abriouel H, Valdivia E, Gálvez A, Martin-Belloso O
Department of Food Technology, University of Lleida, Avda. Alcalde Rovira Roure 191, 25198 Lleida, Spain.
J Dairy Sci. 2009 Jun;92(6):2514-23. doi: 10.3168/jds.2008-1996.
The use of high-intensity pulsed-electric field (HIPEF) and antimicrobial substances of natural origin, such as enterocin AS-48 (AS-48), nisin, and lysozyme, are among the most important nonthermal preservation methods. Thus, the purpose of this study was to evaluate the combined effect on milk inoculated with Staphylococcus aureus of the addition of AS-48 with nisin or lysozyme, or both, together with the use of HIPEF. Synergy was observed in the reduction of Staph. aureus counts with the following combination methods: i) addition of AS-48 and nisin, ii) addition of AS-48 plus use of HIPEF, and iii) addition of AS-48 and nisin plus use of HIPEF. Specifically, when 28 arbitrary units/mL of AS-48 and 20 IU/mL of nisin were added to the milk, and it was treated with HIPEF for 800 mus, over 6 log reductions were observed in the microorganism. In general, Staph. aureus inactivation was dependent on HIPEF treatment time, antimicrobial doses, and medium pH. During storage of the treated milk, survivor population was related to peptide concentration and temperature. Final cell viability was influenced by the sequence in which the treatments were applied: the addition of AS-48 or AS-48 and nisin was more effective before than after HIPEF treatment. The results obtained indicate that the combination of HIPEF and antimicrobials could be of great interest to the dairy industry, although it is necessary to study further the way in which the combined treatments act.
使用高强度脉冲电场（HIPEF）以及天然来源的抗菌物质，如肠球菌素AS-48（AS-48）、乳链菌肽和溶菌酶，是最重要的非热保鲜方法之一。因此，本研究的目的是评估AS-48与乳链菌肽或溶菌酶单独添加或两者同时添加，再结合使用HIPEF对接种金黄色葡萄球菌的牛奶的联合作用。在以下组合方法中观察到了金黄色葡萄球菌数量减少的协同作用：i）添加AS-48和乳链菌肽，ii）添加AS-48并使用HIPEF，iii）添加AS-48和乳链菌肽并使用HIPEF。具体而言，当向牛奶中添加28个任意单位/毫升的AS-48和20国际单位/毫升的乳链菌肽，并对其进行800微秒的HIPEF处理时，观察到微生物数量减少了6个对数级以上。一般来说，金黄色葡萄球菌的失活取决于HIPEF处理时间、抗菌剂量和培养基pH值。在处理后的牛奶储存期间，存活菌数与肽浓度和温度有关。最终的细胞活力受处理应用顺序的影响：在HIPEF处理之前添加AS-48或AS-48和乳链菌肽比之后添加更有效。获得的结果表明，HIPEF和抗菌剂的组合可能对乳制品行业非常有意义，尽管有必要进一步研究联合处理的作用方式。
