SENFIMIZO Department, Section of Phytopathology and Agricultural Microbiology, University of Palermo, Viale delle Scienze 4, 90128 Palermo, Italy.
Food Microbiol. 2011 Aug;28(5):883-90. doi: 10.1016/j.fm.2010.12.003. Epub 2010 Dec 13.
Six strains of non-starter lactic acid bacteria (NSLAB) were used to extend the shelf-life of the fresh cheese Tosèla manufactured with pasteurised cows' milk. The acidification kinetics of three Lactobacillus paracasei, one Lactobacillus rhamnosus and two Streptococcus macedonicus were studied in synthetic milk medium. Lb. paracasei NdP78 and NdP88 and S. macedonicus NdP1 and PB14-1 showed an interesting acidifying capacity and were further characterised for growth in UHT milk and production of antimicrobial compounds. Lb. paracasei NdP78 and S. macedonicus NdP1 grew more than 2 log cycles in 6 h. Lb. paracasei NdP78 was also found to produce a bacteriocin-like inhibitory substance (BLIS) active against Listeria monocytogenes. The four NSLAB strains (singly or in combination) were used to produce experimental pilot-scale cheeses which were compared by a panel. The cheese manufactured with the mixed culture Lb. paracasei NdP78 - S. macedonicus NdP1 was the most appreciated for its sensory properties. The cheeses produced at factory-scale showed higher concentrations of lactobacilli (7.90 log CFU/g) and streptococci (6.10 log CFU/g), but a lower development of coliforms (3.10 log CFU/g) and staphylococci (2.78 log CFU/g) than control cheese (4.86, 4.89, 4.93 and 5.00 log CFU/g of lactobacilli, streptococci, coliforms and staphylococci, respectively) processed without NSLAB addition. The food pathogens Salmonella spp. and Listeria monocytogenes were never detected. The dominance of the species inoculated was demonstrated by denaturing gradient gel electrophoresis (DGGE), whereas strain recognition was evaluated by randomly amplified polymorphic DNA (RAPD)-PCR. From the results obtained, Lb. paracasei NdP78 and S. macedonicus NdP1 were able to persist during the storage of Tosèla cheese and their combination influenced positively the sensory characteristics and shelf-life of the final product.
六种非发酵乳杆菌（NSLAB）菌株被用于延长巴氏杀菌牛奶制成的新鲜奶酪 Tosèla 的保质期。研究了三种副干酪乳杆菌、一种鼠李糖乳杆菌和两种马科氏乳球菌在合成乳培养基中的酸化动力学。Lb. paracasei NdP78 和 NdP88 以及 S. macedonicus NdP1 和 PB14-1 表现出有趣的酸化能力，并进一步研究了它们在超高温乳中的生长和抗菌化合物的生产。Lb. paracasei NdP78 和 S. macedonicus NdP1 在 6 小时内生长超过 2 个对数周期。还发现 Lb. paracasei NdP78 产生一种对单核细胞增生李斯特菌有活性的细菌素样抑制物质（BLIS）。这四种 NSLAB 菌株（单独或组合使用）用于生产实验性 pilot-scale 奶酪，然后由专家组进行比较。使用混合培养物 Lb. paracasei NdP78 - S. macedonicus NdP1 生产的奶酪因其感官特性而最受赞赏。在工厂规模生产的奶酪中，乳杆菌（7.90 log CFU/g）和链球菌（6.10 log CFU/g）的浓度较高，但大肠菌群（3.10 log CFU/g）和葡萄球菌（2.78 log CFU/g）的浓度较低，而对照奶酪（4.86、4.89、4.93 和 5.00 log CFU/g 的乳杆菌、链球菌、大肠菌群和葡萄球菌）的处理则不添加 NSLAB。从未检测到食源性病原体沙门氏菌和单核细胞增生李斯特菌。变性梯度凝胶电泳（DGGE）证明了接种物的优势，而随机扩增多态性 DNA（RAPD）-PCR 则评估了菌株的识别。从结果来看，Lb. paracasei NdP78 和 S. macedonicus NdP1 能够在 Tosèla 奶酪的储存过程中持续存在，并且它们的组合对最终产品的感官特性和保质期产生了积极影响。
