Highly efficient and specific separation of Staphylococcus aureus from lettuce and milk using Dynabeads protein G conjugates

Shuai Wei; Byung-Jae Park; Kun-Ho Seo; Deog-Hwan Oh

doi:10.1007/s10068-016-0233-1

Highly efficient and specific separation of Staphylococcus aureus from lettuce and milk using Dynabeads protein G conjugates

Food Sci Biotechnol. 2016 Oct 31;25(5):1501-1505. doi: 10.1007/s10068-016-0233-1. eCollection 2016.

Authors

Shuai Wei¹, Byung-Jae Park¹, Kun-Ho Seo², Deog-Hwan Oh¹

Affiliations

¹ 1Department of Food Science and Biotechnology, School of Bioconvergence Science and Technology, Kangwon National University, Chuncheon, Gangwon, 24341 Korea.
² 2KU Center for Food Safety, College of Veterinary Medicine, Konkuk University, Seoul, 05029 Korea.

Abstract

An immunomagnetic separation method using antibody-coated Dynabeads^® Protein G was developed for specific and efficient separation of Staphylococcus aureus in lettuce and whole milk. The amount of immunomagnetic beads (IMBs) and conjugation conditions were optimized. A high capture efficiency was obtained with 0.4 mg of IMBs, an immunoreaction time of 20 min, and a separation time of 1 min without wash. Under optimal conditions, the capture efficiency (CE) for 10⁰-10⁵ CFU/mL of S. aureus was higher than 91.46%. The IMBs showed high specificity even with a high constant number (10⁷ CFU/mL) of Bacillus cereus, Micrococcus luteus, and Lactobacillus plantarum. The CE of IMBs against S. aureus at concentrations from 10² to 10⁵ CFU/mL ranged from 78.70 to 94.77% for lettuce and 60.0 to 73.27% for milk samples. This IMS can be an appropriate selection for combining with bacterial detection method or efficient isolation procedure for S. aureus from foods.

Keywords: Dynabeads® Protein G; Staphylococcus aureus; immunomagnetic separation.