Department of Microbiology, Federal University of Viçosa, Viçosa, Brazil.
Biofouling. 2019 Sep;35(8):819-831. doi: 10.1080/08927014.2019.1666267. Epub 2019 Sep 26.
Biofilms can be formed on the surfaces of dairy processing equipment and are a potential source of product contamination. This study evaluated the diversity of multispecies biofilms formed on stainless steel (SS) due to the contaminating microbiota in raw milk. Samples of raw milk were used: one was fresh milk and the other maintained in refrigerated bulk tanks for up to 48 h. The mesophilic aerobic contamination was ∼10 CFU ml in fresh milk and 10 CFU ml in bulk milk. SS coupons were kept immersed in the milk at 7 ±2 °C for 10 days, and every two days, the raw milk was changed for samples of the same origin collected on the current day. After incubation for 10 days, sessile cells in the biofilm reached 10 CFU cm in the presence of fresh milk, and 10 CFU cm in the presence of bulk milk. The genetic diversity analysis showed that Gammaproteobacteria and Bacilli predominated in the biofilms throughout the incubation of both milk samples and these biofilms showed a reduction in diversity over time. The main classes of bacteria found in these biofilms have representatives of great importance since many of them have spoilage potential.
生物膜可以在乳制品加工设备的表面形成，是产品污染的潜在来源。本研究评估了由于原料乳中污染微生物群落在不锈钢（SS）上形成的多物种生物膜的多样性。使用了原料乳样本：一个是新鲜乳，另一个在冷藏大罐中保存长达 48 小时。新鲜乳中的嗜温需氧污染约为 10 CFU ml，大罐乳中的污染约为 10 CFU ml。SS 优惠券在 7 ±2°C 下浸泡在牛奶中 10 天，每两天更换一次当天采集的相同来源的原料乳样本。孵育 10 天后，新鲜乳中生物膜中的固着细胞达到 10 CFU cm，大罐乳中生物膜中的固着细胞达到 10 CFU cm。遗传多样性分析表明，在两种乳样的整个孵育过程中，γ变形菌和芽孢杆菌在生物膜中占主导地位，并且这些生物膜的多样性随时间减少。在这些生物膜中发现的主要细菌类群具有非常重要的代表意义，因为其中许多都具有腐败潜力。
