title: Analysis method for determination of nisin A and nisin Z in cow milk by using liquid chromatography-tandem mass spectrometry.
abstract: Nisin, a polypeptide with antimicrobial properties, is known as a natural preservative. It is used in various foods, including dairy products. This study validated a novel procedure using liquid chromatography-tandem mass spectrometry (LC-MS/MS) for the determination of nisin A and nisin Z in cow milk. An extraction solution of 0.1 M acetate buffer containing 1 M NaCl (pH 2.0) and MeOH (1:1) was used to extract nisin A and nisin Z from milk samples. After the addition of extraction buffers, the samples were homogenized and centrifuged. The supernatant was filtered and injected for LC-MS/MS analysis. The linearity of the analytical method had a high correlation coefficient (r≥0.9987). The limits of quantitation of nisin A and nisin Z were approximately 12.9 and 10.9 µg/kg, respectively. The accuracy of the analytical method in milk ranged from 90.6 to 103.4% for nisin A and from 83.8 to 104.4% for nisin Z. The coefficient of variation values of intra- and interday in milk determined to be less than 5% in both nisin A and nisin Z. Because the proposed method has comparatively high recovery and low coefficient of variation, it seems appropriate for the determination of nisin A and nisin Z in milk samples. As the quantification of nisin A and nisin Z in milk samples by using LC-MS/MS has only been rarely reported until now, this study provides a meaningful technological advance for the dairy industry.
authors.affiliation: Division of Food Additives and Packaging, Department of Food Safety Evaluation, Ministry of Food Drug Safety, Osongsengmyeong 2-ro, Cheongwon-gun, Chungbuk, 363-700, Korea.
authors.forename: Kyung Yuk
authors.initials: KY
authors.lastname: Ko
authors.affiliation: Division of Food Additives and Packaging, Department of Food Safety Evaluation, Ministry of Food Drug Safety, Osongsengmyeong 2-ro, Cheongwon-gun, Chungbuk, 363-700, Korea.
authors.forename: So Ra
authors.initials: SR
authors.lastname: Park
authors.affiliation: Division of Food Additives and Packaging, Department of Food Safety Evaluation, Ministry of Food Drug Safety, Osongsengmyeong 2-ro, Cheongwon-gun, Chungbuk, 363-700, Korea.
authors.forename: Chae A
authors.initials: CA
authors.lastname: Lee
authors.affiliation: Division of Food Additives and Packaging, Department of Food Safety Evaluation, Ministry of Food Drug Safety, Osongsengmyeong 2-ro, Cheongwon-gun, Chungbuk, 363-700, Korea. Electronic address: meehkim@korea.kr.
authors.forename: Meehye
authors.initials: M
authors.lastname: Kim
mesh_terms: D000818:Animals; D002417:Cattle; D002853:Chromatography, Liquid; D005504:Food Analysis / Q000379:methods*; D057230:Limit of Detection; D008892:Milk / Q000737:chemistry*; D009561:Nisin / Q000031:analogs & derivatives* / Q000032:analysis; D015203:Reproducibility of Results; D053719:Tandem Mass Spectrometry
chemical_list: D009561:Nisin; C102526:nisin A; C071364:nisin Z
keywords: liquid chromatography-tandem mass spectrometry; milk; nisin A; nisin Z