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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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Fernández-Pastor S, Castelló DS, López-Mendoza MC. Stability of the Antimicrobial Capacity of Human Milk Against Cronobacter Sakazakii During Handling. J Hum Lact 2021; 37:139-146. [PMID: 32579054 DOI: 10.1177/0890334420932574] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
BACKGROUND Neonatal infections with Cronobacter sakazakii have recently been associated with the consumption of expressed human milk. STUDY AIMS (1) To evaluate whether human milk has antimicrobial capacity against C. sakazakii and (2) to determine the stability of its capacity when it is subjected to various treatments. METHODS The antimicrobial capacity of human milk against C. sakazakii was evaluated using an observational, cross-sectional, comparative design. Mature human milk samples (N = 29) were subjected to different treatments. After incubation at 37°C for 72 hr, samples were compared with fresh milk on the stability of their antimicrobial capacity. Two-way analysis of variance (ANOVA) was performed. RESULTS In fresh milk, counts of C. sakazakii were reduced by 47.26% (SD = 6.74) compared to controls. In treated milk, reductions were: refrigeration at 4°C for 72 hr (M = 33.84, SD = 13.84), freezing at -20°C for 1, 2, and 3 months (M = 40.31, SD = 9.10; M = 35.96, SD = 9.39; M = 26.20, SD = 13.55, respectively), Holder pasteurization (M = 23.56, SD = 15.61), and human milk bank treatment with (M = 14.37, SD = 18.02) and without bovine fortifier (M = 3.70, SD = 23.83). There were significant differences (p < .05) between fresh and treated milk. CONCLUSIONS Human milk has antimicrobial capacity against C. sakazakii. However, its capacity is negatively influenced by common preservation and hygienization methods. Milk should be stored refrigerated for a maximum of 72 hr or frozen for a short period of time.
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Affiliation(s)
- Sandra Fernández-Pastor
- 16731 Department of Animal Production and Food Science and Technology, University CEU-Cardenal Herrera, CEU Universities, Valencia, Spain
| | | | - M C López-Mendoza
- 16731 Department of Animal Production and Food Science and Technology, University CEU-Cardenal Herrera, CEU Universities, Valencia, Spain
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Morato-Rodríguez MDR, Velandia-Rodríguez D, Castañeda S, Crosby M, Vera H. Cronobacter spp. in Common Breast Milk Substitutes, Bogotá, Colombia. Emerg Infect Dis 2019; 24. [PMID: 30226163 PMCID: PMC6154129 DOI: 10.3201/eid2410.172021] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In Bogotá, Colombia, a large number of babies are fed with breast milk substitutes made from corn and plantain starch. We found 34.3% of tested samples to be contaminated with Cronobacter spp.; C. sakazakii was the most recovered species. Our findings underscore the risk for contamination of breast milk substitutes.
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Fu S, Jiang Y, Jiang X, Zhao Y, Chen S, Yang X, Man C. Probe-free label system for rapid detection of Cronobacter genus in powdered infant formula. AMB Express 2018; 8:155. [PMID: 30269246 PMCID: PMC6163125 DOI: 10.1186/s13568-018-0689-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2018] [Accepted: 09/26/2018] [Indexed: 02/08/2023] Open
Abstract
Cronobacter species previously known as Enterobacter sakazakii poses high risks to neonates and infants. In this work a rapid detection method was developed which combined loop-mediated isothermal amplification with lateral flow assay for detection of Cronobacter species in powdered infant formula. The fast amplification reaction without betaine was established and capable of performing DNA replication within 25 min. Based on the novel probe-free labeling methods, we established a lateral flow assay to capture the specific loop-mediated isothermal amplification amplicons which were labeled with fluorescein isothiocyanate and biotin. And the final detection time of this system was within 40 min. The false positive results of the lateral flow assay induced by primer dimer tagged with fluorescein isothiocyanate and biotin were eliminated by Taq single strand DNA binding protein (4 ng/μL). Simultaneously, the efficiency of the fast loop-mediated isothermal amplification assay was achieved. By injection of Taq SSB into the amplification assay as a replacement for betaine, the novel probe-free method could detect Cronobacter species with high specificity and sensitivity at the detection limit in PIF of 101 cfu/g. Our overall strategy has excellent potential in the rapid diagnosis of Cronobacter species label-free by integrating loop-mediated isothermal amplification and lateral flow assay.
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Song X, Shukla S, Lee G, Park S, Kim M. Detection of Cronobacter Genus in Powdered Infant Formula by Enzyme-linked Immunosorbent Assay Using Anti-Cronobacter Antibody. Front Microbiol 2016; 7:1124. [PMID: 27493642 PMCID: PMC4955378 DOI: 10.3389/fmicb.2016.01124] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Accepted: 07/06/2016] [Indexed: 11/13/2022] Open
Abstract
Cronobacter species (Cronobacter spp.) are hazardous foodborne pathogens associated with baby food, powdered infant formula (PIF). To develop a rapid and sensitive method for simultaneous detection of seven Cronobacter spp. in PIF, an indirect non-competitive enzyme-linked immunosorbent assay (INC-ELISA) was developed based on a novel immunoglobulin G (IgG), anti-Cronobacter IgG. The developed INC-ELISA was able to detect seven Cronobacter spp. at concentrations ranging from (5.6 ± 0.30) × 10(3) to (2.1 ± 0.01) × 10(5) colony forming unit (CFU)/mL in pure culture. Further, INC-ELISA employing anti-Cronobacter IgG was applicable for analysis of PIF samples contaminated with less than <10 cells of Cronobacter spp. per 25 g of PIF in 36 h. The developed antibody showed slight cross-reactivity with Franconibacter pulveris (LMG 24057) at high concentration (10(8) CFU/mL). The INC-ELISA method displayed excellent specificity without compromising cross-reactivity with other foodborne pathogens. The INC-ELISA assay method developed in this study using a novel anti-Cronobacter IgG facilitated highly sensitive, efficient, and rapid detection of Cronobacter spp. in baby food.
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Affiliation(s)
- Xinjie Song
- Department of Food Science and Technology, Yeungnam University Gyeongsan, South Korea
| | - Shruti Shukla
- Department of Food Science and Technology, Yeungnam University Gyeongsan, South Korea
| | - Gibaek Lee
- Department of Food Science and Technology, Yeungnam University Gyeongsan, South Korea
| | - Sunhyun Park
- Food Standard Research Center, Korea Food Research Institute Seongnam, South Korea
| | - Myunghee Kim
- Department of Food Science and Technology, Yeungnam University Gyeongsan, South Korea
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