Instituto de Ciência e Tecnologia de Alimentos, Universidade Federal do Rio Grande do Sul, 91501-970 Porto Alegre, Brasil.
J Dairy Res. 2011 Aug;78(3):257-62. doi: 10.1017/S002202991100015X. Epub 2011 Apr 1.
The proteolytic activity of a psychrotrophic strain of Burkholderia cepacia isolated from refrigerated raw milk was characterized. Bur. cepacia produced proteolytic activity during growth at refrigeration temperature, with maximum activity at pH 6-7. The enzyme showed relative thermal stability in the range 40-50°C during 25 min, and maintained 80% its initial activity at 76°C/30 s. Milk coagulation assay showed that the crude protease from Bur. cepacia caused coagulation from day 2 for skimmed milk, whereas coagulation was observed from day 5 for whole milk. The adherence of this strain to stainless steel was evaluated, and the substrata had around 107 CFU/cm2 after 15 to 60 min incubation. Results on biofilm development suggest that this bacterium could adhere and to form biofilms even at refrigeration temperatures. These results indicate that Bur. cepacia may represent a potential hazardous to milk and dairy products.
从冷藏生牛乳中分离到的一株嗜冷伯克霍尔德氏菌的蛋白水解活性得到了研究。Bur. cepacia 在冷藏温度下生长时会产生蛋白水解活性，最适 pH 值为 6-7。该酶在 40-50°C 下具有相对热稳定性，在 76°C/30s 下保持 80%的初始活性。牛奶凝固试验表明，Bur. cepacia 的粗蛋白酶能在第 2 天使脱脂牛奶凝固，而全脂牛奶则在第 5 天观察到凝固。对该菌株在不锈钢上的黏附性进行了评估，在 15-60min 的孵育后，基质上的细菌数量约为 107 CFU/cm2。生物膜形成的结果表明，即使在冷藏温度下，该细菌也能够黏附和形成生物膜。这些结果表明，Bur. cepacia 可能对牛奶和乳制品构成潜在危害。
