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Li Y, Xu Y, Soko WC, Bi H. Quantum dots (QDs) attached magnetic beads (MBs) for on-chip efficient capture and detection of bacteria in ready-to-eat (RTE) foods. Talanta 2024; 273:125880. [PMID: 38484499 DOI: 10.1016/j.talanta.2024.125880] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2024] [Revised: 02/19/2024] [Accepted: 03/04/2024] [Indexed: 04/09/2024]
Abstract
In this study, we established a versatile and simple magnetic-assisted microfluidic method for fast bacterial detection. Quantum dots (QDs) were loaded onto magnetic beads (MBs) to construct performance enhanced on-chip capture of bacteria. Escherichia coli (E. coli), as a model bacterium was studied. CdSe QDs were deposited onto the surface of Fe3O4 MBs through layer-by-layer self-assembly to enhance the loading of antibodies (Abs). MBs functionalized with anti-E. coli antibody molecules in a micropillar-based microfluidic chip were utilized to capture E. coli, and matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) was used for characterization of captured bacteria. This method was found capable of specifically isolating E. coli within the range of 1.0 to 1.0 × 109 CFU/mL, having a detection limit (LOD) of 10 CFU/mL. The average similarity score among mass spectra for the bacterial capture obtained in independent experiments is calculated as 0.97 ± 0.01 (n = 3), which shows this work's excellent reproducibility for bacterial capture. Bacterial growth on ready-to-eat (RTE) foods during its time of storage was successfully monitored. The present protocol has promising potential for microbial control and pathogen detection in the food industry.
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Affiliation(s)
- Yunxing Li
- College of Food Science and Technology, Shanghai Ocean University (SHOU), Hucheng Ring Road 999, Pudong New District, 201306, Shanghai, China.
| | - Yihong Xu
- College of Food Science and Technology, Shanghai Ocean University (SHOU), Hucheng Ring Road 999, Pudong New District, 201306, Shanghai, China.
| | - Winnie C Soko
- College of Food Science and Technology, Shanghai Ocean University (SHOU), Hucheng Ring Road 999, Pudong New District, 201306, Shanghai, China.
| | - Hongyan Bi
- College of Food Science and Technology, Shanghai Ocean University (SHOU), Hucheng Ring Road 999, Pudong New District, 201306, Shanghai, China.
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Salazar-Llorente E, Morales M, Sornoza I, Mariduena-Zavala MG, Gu G, Nou X, Ortiz J, Maldonado-Alvarado P, Cevallos-Cevallos JM. Microbiological Quality of High-Demand Food from Three Major Cities in Ecuador. J Food Prot 2021; 84:128-138. [PMID: 33411929 DOI: 10.4315/jfp-20-271] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Accepted: 09/07/2020] [Indexed: 11/11/2022]
Abstract
ABSTRACT Bacterial foodborne diseases are among the most important public health issues worldwide, but in Ecuador, reports on the microbiological quality of food are scarce. In this cross-sectional study, 450 samples of high-demand Ecuadorian food, including bolon, encebollado, sauces, ceviche, fruit, fruit juice, fruit salad, cheese, raw chicken, and ground beef, were collected from popular street markets in the cities of Guayaquil, Quito, and Cuenca. Populations of total aerobic mesophilic bacteria, total coliforms, fecal coliforms, Escherichia coli, Salmonella enterica, and Listeria monocytogenes were examined on composited samples by plate count following the local regulations (Norma Tecnica Ecuatoriana, Instituto Ecuatoriano de Normalización) for each kind of food. The individual and interaction effects of the city and food type on the levels of each bacterial group were assessed by two-way analysis of variance. Selected colonies from each culture were identified using Biolog OmniLog ID and sequencing of the V3 to V4 region on the 16S rRNA gene. Average total aerobic mesophilic bacteria, total coliform, fecal coliform, and E. coli levels were 5.10 ± 0.12, 2.50 ± 0.16, 1.09 ± 0.12, and 0.83 ± 0.12 log CFU/g or mL, respectively, with significant variations among the cities. The prevalence of Salmonella in chicken and sauces and L. monocytogenes in cheese and fruit salad was greater than 20%. Opportunistic pathogens including Klebsiella pneumoniae, Staphylococcus sciuri, and Enterococcus spp. were frequently identified in the samples from all three cities. High prevalence of spoilage microorganisms such as Bacillus amyloliquefaciens and biocontrol bacteria such as Lactococcus lactis was also observed. This is the first report on the microbiological quality of food from Ecuador. HIGHLIGHTS
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Affiliation(s)
- Enrique Salazar-Llorente
- Escuela Superior Politécnica del Litoral (ESPOL), Centro de Investigaciones Biotecnológicas del Ecuador
| | - Maria Morales
- ESPOL, Facultad de Ingeniería Mecánica y Ciencias de la Produccion, U.S. Department of Agriculture Agricultural Research Service, Beltsville, Maryland, USA
| | - Ivette Sornoza
- ESPOL, Facultad de Ingeniería Mecánica y Ciencias de la Produccion, U.S. Department of Agriculture Agricultural Research Service, Beltsville, Maryland, USA
| | | | - Ganyu Gu
- Environmental Microbiology and Food Safety Laboratory, U.S. Department of Agriculture Agricultural Research Service, Beltsville, Maryland, USA
| | - Xiangwu Nou
- Environmental Microbiology and Food Safety Laboratory, U.S. Department of Agriculture Agricultural Research Service, Beltsville, Maryland, USA
| | - Johana Ortiz
- Department of Biosciences, Food Nutrition and Health Research Unit, Faculty of Chemical Sciences, Cuenca University, Cuenca, Ecuador
| | - Pedro Maldonado-Alvarado
- Escuela Politécnica Nacional, Departamento de Alimentos y Biotecnología, P.O. Box 17-01-2759, Quito, Ecuador
| | - Juan Manuel Cevallos-Cevallos
- Escuela Superior Politécnica del Litoral (ESPOL), Centro de Investigaciones Biotecnológicas del Ecuador.,(ORCID: https://orcid.org/0000-0003-4609-7998 [J.M.C.C.]).,ESPOL, Facultad de Ciencias de la Vida, Campus Gustavo Galindo, Km. 30.5 Vía Perimetral, P.O. Box 09-01-5863, Guayaquil, Ecuador
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