Hughey V L, Wilger P A, Johnson E A
Department of Food Microbiology and Toxicology, University of Wisconsin, Madison 53706.
Appl Environ Microbiol. 1989 Mar;55(3):631-8. doi: 10.1128/aem.55.3.631-638.1989.
Egg white lysozyme killed or prevented growth of Listeria monocytogenes Scott A in several foods. Lysozyme was more active in vegetables than in animal-derived foods that we tested. For maximum activity in certain foods, EDTA was required in addition to lysozyme. Lysozyme with EDTA effectively killed inoculated populations of 10(4) L. monocytogenes per g in fresh corn, fresh green beans, shredded cabbage, shredded lettuce, and carrots during storage at 5 degrees C. Control incubations without lysozyme supported growth of L. monocytogenes to 10(6) to 10(7)/g. Lysozyme had less activity in animal-derived foods, including fresh pork sausage (bratwurst) and Camembert cheese. In bratwurst, lysozyme with EDTA prevented L. monocytogenes from growing for 2 to 3 weeks but did not kill significant numbers of cells and did not prevent eventual growth. The control sausages not containing lysozyme supported rapid and heavy growth, which indicated that lysozyme was bacteriostatic for 2 to 3 weeks in fresh pork sausage. We also prepared Camembert cheese containing 10(4) L. monocytogenes cells per g and investigated the changes during ripening in cheeses supplemented with lysozyme and EDTA. Cheeses with lysozyme by itself or together with EDTA reduced the L. monocytogenes population by approximately 10-fold over the first 3 to 4 weeks of ripening. In the same period, the control cheese wheels without added lysozyme with and without chelator slowly started to grown and eventually reached 10(6) to 10(7) CFU/g after 55 days of ripening.(ABSTRACT TRUNCATED AT 250 WORDS)
蛋清溶菌酶可杀死单核细胞增生李斯特菌Scott A或抑制其在多种食物中的生长。溶菌酶在蔬菜中的活性高于我们测试的动物性食物。为使溶菌酶在某些食物中发挥最大活性，除溶菌酶外还需添加乙二胺四乙酸（EDTA）。溶菌酶与EDTA可有效杀死5℃储存期间新鲜玉米、新鲜四季豆、切丝卷心菜、切丝生菜和胡萝卜中每克接种的10⁴个单核细胞增生李斯特菌。未添加溶菌酶的对照培养物中，单核细胞增生李斯特菌生长至每克10⁶至10⁷个。溶菌酶在动物性食物中的活性较低，包括新鲜猪肉香肠（德式小香肠）和卡芒贝尔奶酪。在德式小香肠中，溶菌酶与EDTA可使单核细胞增生李斯特菌2至3周内不生长，但无法杀死大量细胞，也不能阻止其最终生长。不含溶菌酶的对照香肠支持快速且大量生长，这表明溶菌酶在新鲜猪肉香肠中具有2至3周的抑菌作用。我们还制备了每克含10⁴个单核细胞增生李斯特菌细胞的卡芒贝尔奶酪，并研究了添加溶菌酶和EDTA的奶酪在成熟过程中的变化。单独添加溶菌酶或与EDTA一起添加的奶酪在成熟的前3至4周内可使单核细胞增生李斯特菌数量减少约10倍。在同一时期，未添加溶菌酶且添加或未添加螯合剂的对照奶酪轮开始缓慢生长，成熟55天后最终达到每克10⁶至10⁷个菌落形成单位。（摘要截取自250字）
