Fortina M G, Ricci G, Foschino R, Picozzi C, Dolci P, Zeppa G, Cocolin L, Manachini P L
Dipartimento di Scienze e Tecnologie Alimentari e Microbiologiche, Università di Milano, Milan, Italy.
J Appl Microbiol. 2007 Aug;103(2):445-53. doi: 10.1111/j.1365-2672.2006.03265.x.
To characterize Lactococcus garvieae strains of dairy origin and to determine their technological properties and safety for their possible use in starter culture preparation.
Forty-seven L. garvieae isolates, recovered from two artisanal Italian cheeses were studied, in comparison with 12 fish isolates and the type strain of the species. Phenotypic typing revealed that the strains could be differentiated on the basis of their ecological niche of origin in lactose positive strains (all isolated from dairy sources) and lactose negative strains (all isolated from fish). Furthermore, the strains exhibited a high degree of physiological variability, showing the presence of 26 different biotypes. The strains possessed moderate acidifying and proteolytic activities and did not produce bacteriocins. A safety investigation revealed that all strains were sensitive to vancomycin and moderately resistant to kanamycin; some biotypes were tetracycline resistant. Production of biogenic amines or presence of genes encoding virulence determinants occurred in some isolates.
The prevalence of L. garvieae in some artisanal Italian cheeses can be linked to the typicity of the products. Although in a few cases an antimicrobial resistance or a presence of virulence determinants may imply a potential hygienic risk, most of the strains showed positive properties for their possible adjunction in a starter culture preparation, to preserve the natural bacterial population responsible for the typical sensorial characteristics of the traditional raw milk cheeses.
L. garvieae strains can be considered an important part of the microbial population associated with the natural fermentation of artisanal Italian cheeses. A deepened characterization of the strains may aid in understanding the functional and ecological significance of their presence in dairy products and in selecting new strains for the dairy industry.
对源自乳制品的加氏乳球菌菌株进行特性分析，并确定其技术特性和安全性，以评估其用于制备发酵剂的可能性。
研究了从两种意大利手工奶酪中分离出的47株加氏乳球菌，与12株鱼源分离株及该菌种的模式菌株进行比较。表型分型显示，这些菌株可根据其起源的生态位分为乳糖阳性菌株（均从乳制品来源分离）和乳糖阴性菌株（均从鱼中分离）。此外，这些菌株表现出高度的生理变异性，共有26种不同的生物型。这些菌株具有适度的酸化和蛋白水解活性，且不产生细菌素。安全性调查显示，所有菌株对万古霉素敏感，对卡那霉素中度耐药；部分生物型对四环素耐药。部分分离株中存在生物胺的产生或编码毒力决定因素的基因。
加氏乳球菌在某些意大利手工奶酪中的存在可能与产品的典型性有关。尽管在少数情况下，抗菌抗性或毒力决定因素的存在可能意味着潜在的卫生风险，但大多数菌株在制备发酵剂时表现出积极特性，有助于保留负责传统生乳奶酪典型感官特征的天然细菌群体。
加氏乳球菌菌株可被视为与意大利手工奶酪自然发酵相关的微生物群体的重要组成部分。对这些菌株的深入特性分析可能有助于理解它们在乳制品中存在的功能和生态意义，并为乳制品行业选择新菌株提供帮助。
