Dipartimento Scienze Agrarie, Alimentari e Forestali, Università degli Studi di Palermo, Viale delle Scienze 4, 90128 Palermo, Italy.
Istituto Zooprofilattico Sperimentale della Sicilia "Adelmo Mirri", Via G. Marinuzzi 3, 90129 Palermo, Italy.
Int J Food Microbiol. 2019 Oct 16;307:108277. doi: 10.1016/j.ijfoodmicro.2019.108277. Epub 2019 Jul 29.
This work was carried out to pursue a double objective: to improve the hygienic safety of cheeses produced from raw ewes' milk; and to produce a new typology of raw ewes' milk through the application of "Grana" technology for which the name "Gran Ovino" was chosen. With this in mind, raw milk from an individual farm was transformed under controlled conditions at a dairy pilot plant. The production technology included the partial skimming of the evening and morning milk mixture by cream surfacing and the addition of a natural whey starter cultures (NWSC) prepared with four selected Streptococcus thermophilus strains (PON6, PON244, PON261 e PON413). Ten microbial groups were investigated by plate counts from raw milk until ripened cheeses. Lactic acid bacteria (LAB) were in the range 10-10 CFU/ml before NWSC addition. After curdling, this group increased by 3 log cycles and was counted at 10 CFU/g after curd cooking. A rapid pH drop (to 6.05) was registered after almost 3 h from NWSC addition. The levels of members of the Enterobacteriaceae family were at about 10 CFU/ml in raw milk and decreased after curd cooking to 1 log cycle. A similar behavior was shown by the other undesired microbial groups and a complete disappearance of staphylococci was registered. The microbiological counts of 9-month ripened cheeses showed the dominance of LAB and undetectable levels of the undesired bacteria. MiSeq Illumina was applied to better investigate the bacterial composition of ripened cheeses and this technique evidenced that the majority of OTUs belonged to Lactobacillus and Streptococcus genera. The final cheeses were characterized by 67.65% dry matter of which 41.85% of fats and 47.02% of proteins. The main cheese fatty acids were palmitic, oleic and myristic acids and the saturated fatty acids/unsaturated fatty acids ratio was 2.17. Forty-one volatile compounds, including acids, esters, ketones, alcohols, aldehydes, phenols and one terpene were emitted from the cheese. Sensory evaluation showed a general appreciation for the new cheese product by judges.
提高生羊乳奶酪的卫生安全性；通过应用“格拉纳”技术生产一种新型生羊乳奶酪，命名为“Gran Ovino”。为此，在乳品中试工厂对来自单个农场的生牛乳进行了控制条件下的转化。生产技术包括通过奶油表面浮出对早晚奶混合物进行部分撇脂，以及添加用 4 株选定的嗜热链球菌（PON6、PON244、PON261 和 PON413）制备的天然乳清发酵剂（NWSC）。从生牛乳到成熟奶酪，通过平板计数法研究了 10 个微生物群。在添加 NWSC 之前，乳酸菌（LAB）的数量在 10-10 CFU/ml 范围内。凝乳后，该菌群增加了 3 个对数周期，在凝乳烹饪后计数为 10 CFU/g。添加 NWSC 后近 3 小时，pH 值迅速下降（至 6.05）。生牛乳中肠杆菌科家族成员的水平约为 10 CFU/ml，在凝乳烹饪后下降 1 个对数周期。其他不受欢迎的微生物群也表现出类似的行为，葡萄球菌完全消失。9 个月成熟奶酪的微生物计数显示，LAB 占主导地位，不可检测到不受欢迎的细菌。MiSeq Illumina 被用于更好地研究成熟奶酪的细菌组成，该技术表明大多数 OTUs 属于乳杆菌属和链球菌属。最终奶酪的干物质含量为 67.65%，其中脂肪含量为 41.85%，蛋白质含量为 47.02%。奶酪的主要脂肪酸是棕榈酸、油酸和肉豆蔻酸，饱和脂肪酸/不饱和脂肪酸的比例为 2.17。从奶酪中释放出 41 种挥发性化合物，包括酸、酯、酮、醇、醛、酚和一种萜烯。感官评价显示，评委们普遍对这种新奶酪产品表示赞赏。
