Phage inactivation of Staphylococcus aureus in fresh and hard-type cheeses
Phage inactivation of Staphylococcus aureus in fresh and hard-type cheeses
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DOI：
10.1016/j.ijfoodmicro.2012.06.012
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发表时间：
2012-08-01
影响因子：
5.4
通讯作者：
Rodriguez, Ana
中科院分区：
文献类型：
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作者：
Bueno, Edita;Garcia, Pilar;Rodriguez, Ana
噬菌体被认为是食品中的天然抗菌剂，因为它们能够特异性感染和裂解食源性致病菌，而不干扰固有微生物群。之前从乳制品环境中分离出的两种金黄色葡萄球菌专性裂解噬菌体（vB_SauS-phi-IPLA35 和 vB_SauS-phi-SauS-IPLA88），评估了它们作为新鲜奶酪和硬质奶酪中针对这种病原微生物的生物防治剂的潜力。巴氏灭菌奶被金黄色葡萄球菌 Sa9（约 10(6) CFU/mL）污染，并且还添加了两种裂解噬菌体的混合物（约 10(6) PFU/mL）。出于控制目的，在生产奶酪时不添加噬菌体。在这两种类型的奶酪中，噬菌体的存在导致凝结过程中金黄色葡萄球菌活菌数量的减少。在测试的新鲜奶酪中，与对照奶酪相比，3 小时内金黄色葡萄球菌减少了 3.83 log CFU/g，并且活菌计数在 6 小时后低于检测限。在凝结过程结束时（24 小时），测试奶酪和对照奶酪中均未检测到葡萄球菌菌株，值得注意的是，在冷藏过程中没有发生再生长。在硬奶酪中，噬菌体的存在导致葡萄球菌数量持续减少。与对照奶酪相比，凝乳中金黄色葡萄球菌的活菌数减少了 4.64 log CFU/g。成熟结束时，在测试奶酪中仍检测到 1.24 log CFU/g 的葡萄球菌菌株，而在对照奶酪中则检测到 6.73 log CFU/g。发酵剂菌株不受奶酪制作过程中噬菌体存在的影响，并且奶酪保持了其预期的物理化学特性。 (C) 2012 Elsevier B.V. 保留所有权利。
Bacteriophages are regarded as natural antibacterial agents in food since they are able to specifically infect and lyse food-borne pathogenic bacteria without disturbing the indigenous microbiota. Two Staphylococcus aureus obligately lytic bacteriophages (vB_SauS-phi-IPLA35 and vB_SauS-phi-SauS-IPLA88), previously isolated from the dairy environment, were evaluated for their potential as biocontrol agents against this pathogenic microorganism in both fresh and hard-type cheeses. Pasteurized milk was contaminated with S. aureus Sa9 (about 10(6) CFU/mL) and a cocktail of the two lytic phages (about 10(6) PFU/mL) was also added. For control purposes, cheeses were manufactured without addition of phages. In both types of cheeses, the presence of phages resulted in a notorious decrease of S. aureus viable counts during curdling. In test fresh cheeses, a reduction of 3.83 log CFU/g of S. aureus occurred in 3 h compared with control cheese, and viable counts were under the detection limits after 6 h. The staphylococcal strain was undetected in both test and control cheeses at the end of the curdling process (24 h) and, of note, no re-growth occurred during cold storage. In hard cheeses, the presence of phages resulted in a continuous reduction of staphylococcal counts. In curd, viable counts of S. aureus were reduced by 4.64 log CFU/g compared with the control cheeses. At the end of ripening, 1.24 log CFU/g of the staphylococcal strain was still detected in test cheeses whereas 6.73 log CFU/g was present in control cheeses. Starter strains were not affected by the presence of phages in the cheese making processes and cheeses maintained their expected physico-chemical properties. (C) 2012 Elsevier B.V. All rights reserved.