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Fu S, Qin X, Wang Z, Yang X, Chen S, Yang T, Jin H, Man C, Jiang Y. Screening of specific nucleic acid targets for Cronobacter sakazakii and visual detection by loop-mediated isothermal amplification and lateral flow dipstick method in powdered infant formula. J Dairy Sci 2021; 104:5152-5165. [PMID: 33663822 DOI: 10.3168/jds.2020-19427] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Accepted: 12/04/2020] [Indexed: 11/19/2022]
Abstract
Due to the lack of specific genes for rapid detection methods of Cronobacter sakazakii in food samples, whole genome sequence analysis was performed in this investigation using the basic local alignment search tool. Forty-two DNA fragments unique to C. sakazakii were mined, then primers were designed and screened by PCR and loop-mediated isothermal amplification (LAMP). Two primer sets, CS1 and CS31, were found as specific and stable primers, with their corresponding nucleic acid targets the CSK29544_00235 gene and CSK29544_03484 gene, respectively. Furthermore, compared with 3 genes reported previously, these 2 genes were verified as more specific to C. sakazakii among Cronobacter species, by sequence similarity alignment using Cronobacter MLST databases (http://pubmlst.org/cronobacter). The specificity of the LAMP reaction approached 100% by using 48 bacterial strains, which included 22 C. sakazakii strains. Subsequently, LAMP was combined with visual lateral flow dipstick (LFD) based on the above 2 nucleic acid targets, and was demonstrated as a rapid, efficient method with high specificity. Finally, the detection sensitivity of this assay system for pure cultures and artificially contaminated milk was measured as 4.5 × 100 cfu/mL and 5.7 × 101 cfu/g, respectively. Total time to detection for this assay was within 2 h. Thus, the establishment of this LAMP-LFD method shows great significance and potential for rapid detection of C. sakazakii in powdered infant formula.
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Affiliation(s)
- Shiqian Fu
- Key Laboratory of Dairy Science, Ministry of Education, College of Food Science, Northeast Agricultural University, Harbin, 150030, China
| | - Xue Qin
- Key Laboratory of Dairy Science, Ministry of Education, College of Food Science, Northeast Agricultural University, Harbin, 150030, China
| | - Zhenghui Wang
- Key Laboratory of Dairy Science, Ministry of Education, College of Food Science, Northeast Agricultural University, Harbin, 150030, China
| | - Xinyan Yang
- Key Laboratory of Dairy Science, Ministry of Education, College of Food Science, Northeast Agricultural University, Harbin, 150030, China
| | - Sihan Chen
- Key Laboratory of Dairy Science, Ministry of Education, College of Food Science, Northeast Agricultural University, Harbin, 150030, China
| | - Tao Yang
- Key Laboratory of Dairy Science, Ministry of Education, College of Food Science, Northeast Agricultural University, Harbin, 150030, China
| | - Haonan Jin
- Key Laboratory of Dairy Science, Ministry of Education, College of Food Science, Northeast Agricultural University, Harbin, 150030, China
| | - Chaoxin Man
- Key Laboratory of Dairy Science, Ministry of Education, College of Food Science, Northeast Agricultural University, Harbin, 150030, China.
| | - Yujun Jiang
- Key Laboratory of Dairy Science, Ministry of Education, College of Food Science, Northeast Agricultural University, Harbin, 150030, China.
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