Sun Lang, Forauer Emily C, Brown Stephanie R B, D'Amico Dennis J
Department of Animal Science, University of Connecticut, Agricultural Biotechnology Laboratory, 1390 Storrs Road, U-4163, Storrs, CT, 06269-4163, USA.
Department of Pathobiology and Veterinary Science, University of Connecticut, 61 North Eagleville Road, U-3089, Storrs, CT, 06269-3089, USA.
Food Microbiol. 2021 May;95:103683. doi: 10.1016/j.fm.2020.103683. Epub 2020 Nov 26.
Listeria monocytogenes can form persistent biofilms on food processing surfaces, resulting in cross-contamination of food products, including milk and milk products. Natural glycolipids are a promising intervention to control undesirable microbes due to their antimicrobial activity and low toxicity. This study aimed to determine the antimicrobial activity of glycolipids to control L. monocytogenes biofilms as well as in milk and on Queso Fresco. Application of a natural glycolipid product significantly reduced biofilm-associated L. monocytogenes on both polystyrene and stainless steel at concentrations as low as 45 mg/L. When added to UHT skim milk, a concentration of 1000 mg/L inhibited L. monocytogenes growth through 7 days of storage at 7 °C, and application of 1300 and 1500 mg/L reduced counts to levels below the limit of enumeration at day 21. In contrast, 2000 mg/L were necessary to inhibit growth through 7 days in whole milk. Glycolipid solutions at concentrations ≥10% reduced L. monocytogenes counts on Queso Fresco through 7 days when applied as a dip. Overall, natural glycolipids have potential as a natural alternative for the removal of biofilms and as an antimicrobial to control L. monocytogenes in milk and milk products with short shelf lives.
单核细胞增生李斯特菌可在食品加工表面形成持久性生物膜，导致包括牛奶和奶制品在内的食品受到交叉污染。天然糖脂因其抗菌活性和低毒性，是控制有害微生物的一种有前景的干预手段。本研究旨在确定糖脂对控制单核细胞增生李斯特菌生物膜以及在牛奶和新鲜奶酪中的抗菌活性。一种天然糖脂产品在低至45毫克/升的浓度下，就能显著减少聚苯乙烯和不锈钢表面与生物膜相关的单核细胞增生李斯特菌。添加到超高温灭菌脱脂牛奶中时，1000毫克/升的浓度可在7℃储存7天的时间内抑制单核细胞增生李斯特菌生长，而在第21天时，1300毫克/升和1500毫克/升的添加量可使菌数降至低于计数限值的水平。相比之下，在全脂牛奶中，需要2000毫克/升的浓度才能在7天内抑制生长。当以浸泡方式应用时，浓度≥10%的糖脂溶液可在7天内减少新鲜奶酪上的单核细胞增生李斯特菌数量。总体而言，天然糖脂有潜力作为一种天然替代品，用于去除生物膜，并作为一种抗菌剂，来控制保质期较短的牛奶和奶制品中的单核细胞增生李斯特菌。
