Abstract Italian authorities reported in 2010 that mozzarella imported from Germany turned blue after opening the package. The “blue mozzarella” defect was associated with Pseudomonas fluorescens strains contaminating processing water in some dairy plants. Afterwards, similar episodes occurred in various European countries and the USA, all characterized by the development of an intense blue discoloration on the surface of fresh cheeses when exposed to air. Recent research on the presumptive causal microorganisms and the metabolites associated with the blue discoloration has contributed to elucidate the bacterial species and pigments responsible for this particular type of spoilage. Quorum sensing mechanisms may induce the production of blue pigment and free aromatic amino acids may enhance its biosynthesis. Physicochemical characteristics of fresh cheeses favorable for growth of psychrotrophic bacteria and long shelf life periods demanded by large supermarket chains contribute to explain the increasing incidence of blue discoloration. Appropriate cleaning and disinfection programs and addition of pepsin-digested lactoferrin are of great help in solving the problem.

中文翻译：

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新鲜奶酪的蓝色变色：与荧光假单胞菌特定污染相关的全球性缺陷

摘要 意大利当局在 2010 年报告说，从德国进口的马苏里拉奶酪打开包装后变成蓝色。“蓝色马苏里拉”缺陷与荧光假单胞菌菌株污染一些乳制品厂的加工水有关。此后，欧洲各国和美国也发生了类似事件，其特点是新鲜奶酪暴露在空气中时，表面会出现强烈的蓝色变色。最近对假定的致病微生物和与蓝色变色相关的代谢物的研究有助于阐明导致这种特定类型腐败的细菌种类和色素。群体感应机制可能会诱导蓝色色素的产生，而游离芳香族氨基酸可能会增强其生物合成。新鲜奶酪的理化特性有利于嗜冷细菌的生长，大型超市连锁店要求的保质期长，这有助于解释蓝色变色发生率的增加。适当的清洁和消毒程序以及添加胃蛋白酶消化的乳铁蛋白对解决问题有很大帮助。