Valladao M, Sandine W E
Department of Microbiology, Oregon State University Corvallis 97331-3804.
J Dairy Sci. 1994 Jun;77(6):1509-14. doi: 10.3168/jds.S0022-0302(94)77090-9.
A reverse-phase HPLC method is described that permits detection of quaternary ammonium sanitizers in milk. The commercial mixture of quaternary ammonium sanitizer used, n-alkyl (50% C14, 40% C12, and 10% C16) dimethyl benzyl ammonium chloride, was extracted from raw and homogenized milks by the Mojonnier milk fat extraction protocol, selectively eluted from the reverse-phase column in the presence of organic solvent and ion-pairing agent, and then analyzed by diode array detection at 217 and 280 nm. Quaternary ammonium sanitizer concentrations in augmented milk samples in the range of 1.0 to 60 micrograms/ml were analyzed with high precision as indicated by a small variance around the mean. Starter culture strains currently in use for manufacture of various fermented milk products available in the Department of Microbiology Culture Collection were examined for their sensitivity to quaternary ammonium sanitizer. All strains were greatly inhibited by as little as 20 micrograms/ml in milk; some were inhibited by only 10 micrograms/ml.
本文描述了一种反相高效液相色谱法，可用于检测牛奶中的季铵消毒剂。所用的季铵消毒剂商业混合物，即正烷基（50% C14、40% C12和10% C16）二甲基苄基氯化铵，通过莫乔尼尔乳脂肪提取方法从生乳和均质乳中提取，在有机溶剂和离子对试剂存在的情况下从反相柱中选择性洗脱，然后通过二极管阵列在217和280 nm处进行检测。强化牛奶样品中季铵消毒剂浓度在1.0至60微克/毫升范围内，分析结果显示精度较高，平均值周围的方差较小。对微生物学培养物保藏中心现有的用于生产各种发酵乳制品的发酵剂菌株进行了季铵消毒剂敏感性检测。所有菌株在牛奶中低至20微克/毫升时就受到极大抑制；有些菌株仅在10微克/毫升时就受到抑制。
