Belfiore C, Castellano P, Vignolo G
Centro de Referencia para Lactobacilos (CERELA), CONICET, Chacabuco 145, T4000ILC Tucumán, Argentina.
Food Microbiol. 2007 May;24(3):223-9. doi: 10.1016/j.fm.2006.05.006. Epub 2006 Sep 5.
The inhibitory activity of lactocin 705/AL705 (2133 arbitrary units per ml (AU ml(-1))), two bacteriocins produced by Lactobacillus curvatus CRL705 and nisin (1066AU ml(-1)) produced by Lactococcus lactis CRL1109 in combination with chelating agents against Escherichia coli strains in TSB medium at 21 and 6 degrees C was investigated. Treatment with EDTA (500 and 1000 mm) and Na lactate (800 mm) alone produced a variable effect depending on the strain, Na lactate being inhibitory against E. coli NCTC12900 at both assayed temperatures while EDTA (1000 mm) led to its inactivation only at 6 degrees C. Direct and deferred strategies using EDTA and Na lactate showed that the direct addition of bacteriocins and chelators was not as effective as compared to deferred treatments. When the deferred treatment effectiveness was evaluated at 6 degrees C, the use of EDTA (500 and 1000 mm) and Na lactate (800 mm) in combination with lactocin 705/AL705 demonstrated to be the most inhibitory strategy against both E. coli strains. Nevertheless, treatments with chelators and bacteriocins was highly dependent upon strain sensitivity. Permeabilization of the outer membrane of E. coli strains with EDTA and Na lactate combined with lactocin 705/AL705 showed to be valuable in controlling this foodborne bacteria at low temperatures.
研究了弯曲乳杆菌CRL705产生的两种细菌素——乳酸乳球菌素705/AL705（2133任意单位每毫升（AU ml⁻¹））和乳酸乳球菌CRL1109产生的乳链菌肽（1066AU ml⁻¹）与螯合剂联合在21℃和6℃的胰酪大豆胨培养基中对大肠杆菌菌株的抑制活性。单独用EDTA（500和1000 mM）和乳酸钠（800 mM）处理产生的效果因菌株而异，乳酸钠在两个测定温度下均对大肠杆菌NCTC12900有抑制作用，而EDTA（1000 mM）仅在6℃导致其失活。使用EDTA和乳酸钠的直接和延迟策略表明，与延迟处理相比，直接添加细菌素和螯合剂的效果不佳。当在6℃评估延迟处理效果时，使用EDTA（500和1000 mM）和乳酸钠（800 mM）与乳酸乳球菌素705/AL705联合被证明是对两种大肠杆菌菌株最具抑制性的策略。然而，用螯合剂和细菌素处理高度依赖于菌株敏感性。用EDTA和乳酸钠与乳酸乳球菌素705/AL705联合使大肠杆菌菌株外膜通透性增加，这在低温下控制这种食源细菌方面显示出有价值。
