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Wu X, Xie B, Qiao Y, Yuan S, Du W. μMET: A Novel Reusable Microfluidic Chip for Precision Microbial Enumeration Tests. Anal Chem 2024; 96:630-635. [PMID: 38163292 DOI: 10.1021/acs.analchem.3c04889] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2024]
Abstract
This work describes μMET, a novel microfluidic device for precise microbial enumeration tests (MET), essential in pharmaceutical, cosmetic, and food industries for ensuring microbiological safety standards. The μMET chip, comprising two hydrophobic glass plates, features a 15-μm deep μMET chamber enhanced by nanopillars and air supply units, facilitating both immediate and growth-dependent MET. Experimental results, with E. coli as a model bacterium, demonstrate that μMET provides counting linearity that outperforms traditional hemocytometers. The chip's design mitigates challenges like evaporation and ensures high-resolution imaging, making it a cost-effective and reusable alternative to conventional methods. Notably, bright-field μMET eliminates the need for fluorescent staining, streamlining operations with deep-learning algorithms for bacterial counts. Furthermore, we have developed a high-parallel μMET chip featuring 16 counting chambers, enhancing throughput and accommodating immediate and growth-dependent MET approaches. Its innovative design and adaptability render the μMET chip as a valuable tool for microbiology, medicine, and industry applications.
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Affiliation(s)
- Xiaolin Wu
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
- College of Life Sciences and Savaid Medical School, University of the Chinese Academy of Sciences, Beijing 10049, China
| | - Bingliang Xie
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
- College of Life Sciences and Savaid Medical School, University of the Chinese Academy of Sciences, Beijing 10049, China
| | - Yuxin Qiao
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Shuai Yuan
- China National Pharmaceutical Foreign Trade Corporation, Beijing 100029, China
| | - Wenbin Du
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
- College of Life Sciences and Savaid Medical School, University of the Chinese Academy of Sciences, Beijing 10049, China
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Cruz-Facundo IM, Toribio-Jiménez J, Castro-Alarcón N, Leyva-Vázquez MA, Rodríguez-Ruíz HA, Pérez-Olais JH, Adame-Gómez R, Rodríguez-Bataz E, Reyes-Roldán J, Muñoz-Barrios S, Ramírez-Peralta A. Bacillus cereus in the Artisanal Cheese Production Chain in Southwestern Mexico. Microorganisms 2023; 11:1290. [PMID: 37317264 DOI: 10.3390/microorganisms11051290] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 05/09/2023] [Accepted: 05/13/2023] [Indexed: 06/16/2023] Open
Abstract
BACKGROUND Bacillus cereus is associated with milk, dairy product, and dairy farm contamination. The aim of this study was to characterize strains of B. cereus in the small-scale artisanal cheese production chain in southwestern Mexico. METHODS 130 samples were collected. B. cereus isolation was performed on Mannitol Egg Yolk Polymyxin (MYP) agar. Genotyping, enterotoxigenic profile, and determination of genes involved in the formation of B. cereus biofilm were performed by PCR. An antimicrobial susceptibility test was made by broth microdilution assay. The phylogenetic analysis was performed by amplification and sequencing of 16s rRNA. RESULTS B. cereus sensu lato was isolated and molecularly identified in 16 samples and B. cereus sensu stricto (B. cereus) was the most frequently isolated and identified species (81.25%). Of all the isolated B. cereus sensu lato strains, 93.75% presented at least one gene for some diarrheagenic toxins, 87.5% formed biofilms, and 18.75% were amylolytic. All B. cereus sensu lato strains were resistant to beta-lactams and folate inhibitors. A close phylogenetic relationship between isolates was found between the cheese isolates and the air isolates. CONCLUSIONS Strains of B. cereus sensu lato were found in small-scale artisanal cheeses on a farm in southwestern Mexico.
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Affiliation(s)
- Itzel-Maralhi Cruz-Facundo
- Laboratorio de Investigación en Patometabolismo Microbiano, Universidad Autónoma de Guerrero, Guerrero 39074, Mexico
| | - Jeiry Toribio-Jiménez
- Laboratorio de Investigación en Microbiología Molecular y Biotecnología Ambiental, Universidad Autónoma de Guerrero, Guerrero 39074, Mexico
| | - Natividad Castro-Alarcón
- Laboratorio de Investigación en Microbiologia, Universidad Autónoma de Guerrero, Guerrero 39074, Mexico
| | - Marco-Antonio Leyva-Vázquez
- Laboratorio de Investigación en Biomedicina Molecular, Universidad Autónoma de Guerrero, Guerrero 39074, Mexico
| | - Hugo-Alberto Rodríguez-Ruíz
- Laboratorio de Investigación en Biomedicina Molecular, Universidad Autónoma de Guerrero, Guerrero 39074, Mexico
- Laboratorio de Investigación en Obesidad y Diabetes, Universidad Autónoma de Guerrero, Guerrero 39074, Mexico
| | - José-Humberto Pérez-Olais
- Unidad de Investigación en Virología y Cancer, Hospital Infantil de México Federico Gomez, Ciudad de Mexico 06720, Mexico
| | - Roberto Adame-Gómez
- Laboratorio de Investigación en Patometabolismo Microbiano, Universidad Autónoma de Guerrero, Guerrero 39074, Mexico
| | - Elvia Rodríguez-Bataz
- Laboratorio de Investigación en Parasitologia, Universidad Autónoma de Guerrero, Guerrero 39074, Mexico
| | - Joel Reyes-Roldán
- Laboratorio de Investigación en Patometabolismo Microbiano, Universidad Autónoma de Guerrero, Guerrero 39074, Mexico
| | - Salvador Muñoz-Barrios
- Laboratorio de Investigación en Inmunotoxigenomica, Universidad Autónoma de Guerrero, Guerrero 39074, Mexico
| | - Arturo Ramírez-Peralta
- Laboratorio de Investigación en Patometabolismo Microbiano, Universidad Autónoma de Guerrero, Guerrero 39074, Mexico
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Ott LC, Jochum J, Burrough L, Clark S, Keener K, Mellata M. High voltage atmospheric cold plasma inactivation of Listeria monocytogenes in fresh Queso Fresco cheese. Food Microbiol 2022; 105:104007. [DOI: 10.1016/j.fm.2022.104007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Revised: 02/09/2022] [Accepted: 02/21/2022] [Indexed: 11/25/2022]
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Wan Z, Misra N, Li G, Keener KM. High voltage atmospheric cold plasma treatment of Listeria innocua and Escherichia coli K-12 on Queso Fresco (fresh cheese). Lebensm Wiss Technol 2021. [DOI: 10.1016/j.lwt.2021.111406] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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Holle MJ, Miller MJ. Lytic characterization and application of listerial endolysins PlyP40 and PlyPSA in queso fresco. JDS COMMUNICATIONS 2021; 2:47-50. [PMID: 36338773 PMCID: PMC9623677 DOI: 10.3168/jdsc.2020-0013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Accepted: 12/07/2020] [Indexed: 11/19/2022]
Abstract
PlyP40 had lytic efficacy against a broad range of Listeria PlyP40 and PlyPSA were able to maintain lytic activity at refrigeration temperature Lytic activity of PlyP40 decreased as pH increased, whereas that of PlyPSA increased PlyP40 and PlyPSA maintained lytic activity within the queso fresco (QF) salt range PlyP40 and PlyPSA were able to decrease counts of Listeria monocytogenes in QF
Queso fresco (QF) is a fresh Hispanic-style cheese that is commonly associated with the human foodborne pathogen Listeria monocytogenes and outbreaks of listeriosis in the United States. Endolysins, cell wall hydrolases derived from bacteriophages, are promising candidates for controlling bacterial pathogens in food systems. In this study, we characterized the lytic capabilities of 2 endolysins, PlyP40 and PlyPSA, under varying conditions (pH, temperature, salt concentration) and compared their activities with those of the previously described endolysin PlyP100. We showed that PlyP40 was effective, showing at least a 33% reduction in cellular debris, against a broader range of Listeria than PlyPSA, which showed little lytic activity toward Listeria strains not from serovar 4. Both endolysins were also capable of maintaining lytic activity to varying extents at refrigeration temperature. The effect of salt concentration and pH differed between PlyP40 and PlyPSA. Furthermore, we added the endolysins to QF and monitored their ability to control L. monocytogenes contamination over 28 d of cold storage. Both PlyP40 and PlyPSA were capable of lowering QF inoculum cell counts compared with the control; however, both were less effective than the previously characterized PlyP100. Further characterization of endolysins will continue to open opportunities to optimization and implementation in a variety of food matrices for controlling pathogen contamination.
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Ibarra-Sánchez LA, Kong W, Lu T, Miller MJ. Efficacy of nisin derivatives with improved biochemical characteristics, alone and in combination with endolysin PlyP100 to control Listeria monocytogenes in laboratory-scale Queso Fresco. Food Microbiol 2020; 94:103668. [PMID: 33279091 DOI: 10.1016/j.fm.2020.103668] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2020] [Revised: 10/01/2020] [Accepted: 10/26/2020] [Indexed: 11/28/2022]
Abstract
Nisin is an antimicrobial peptide that is commonly used as a food preservative and capable of inhibiting the pathogen Listeria monocytogenes. However, nisin is ineffective in controlling L. monocytogenes in Queso Fresco (QF). To address the challenge, in this work, we used synthetic biology strategies to create a series of nisin A derivatives by substituting residues 27, 30, 31 and 32 with positively charged amino acids (H, K and R). Our results showed that nisin derivatives exhibited reduced antilisterial activity in vitro compared to nisin A; however, they were all more stable under QF-like experimental conditions (pH 7 + 22% milk fat), notably H27/31K. Compared to nisin A, the derivatives H31K and V32K exhibited slight antilisterial improvement in QF and H27/31K was able to reduce the initial population of L. monocytogenes by up to 1.5 Log CFU/g. L. monocytogenes isolates exhibited similar susceptibility to nisin A or H27/31K after 7 or 14 days of nisin exposure in QF. Notably, when combined with endolysin PlyP100, the application of H27/31K resulted in non-enumerable levels of L. monocytogenes after 14 days of cold storage. Our results highlight the potential of bioengineered nisin derivatives for stabilized and enhanced control of L. monocytogenes in QF.
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Affiliation(s)
- Luis A Ibarra-Sánchez
- Department of Food Science & Human Nutrition, University of Illinois, Urbana, IL, USA
| | - Wentao Kong
- Department of Bioengineering, University of Illinois, Urbana, IL, USA
| | - Ting Lu
- Department of Bioengineering, University of Illinois, Urbana, IL, USA
| | - Michael J Miller
- Department of Food Science & Human Nutrition, University of Illinois, Urbana, IL, USA.
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Henderson L, Cabrera-Villamizar L, Skeens J, Kent D, Murphy S, Wiedmann M, Guariglia-Oropeza V. Environmental conditions and serotype affect Listeria monocytogenes susceptibility to phage treatment in a laboratory cheese model. J Dairy Sci 2019; 102:9674-9688. [DOI: 10.3168/jds.2019-16474] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Accepted: 07/02/2019] [Indexed: 01/01/2023]
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Challenge Studies to Determine the Ability of Foods to Support the Growth of Listeria monocytogenes. Pathogens 2018; 7:pathogens7040080. [PMID: 30301168 PMCID: PMC6313757 DOI: 10.3390/pathogens7040080] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Revised: 10/01/2018] [Accepted: 10/01/2018] [Indexed: 11/30/2022] Open
Abstract
Listeria monocytogenes is a foodborne pathogen that causes listeriosis, a relatively rare, but potentially fatal, disease, with a mortality rate of 20–30%. In general, European Regulations require the absence of L. monocytogenes in five samples of 25 g before the food has left the producer, but if the food has been demonstrated not to support the growth of L. monocytogenes, up to 100 cfu g−1 are allowed in the food (except for foods for infants or medical purposes) during its shelf-life under reasonably foreseeable storage conditions. It is important for food producers to determine if their food supports the growth of L. monocytogenes. The European Union Reference Laboratory for L. monocytogenes published a Technical Guidance document for conducting shelf-life studies on L. monocytogenes in ready-to-eat foods in June 2014. Primarily based on the EURL guidance document for conducting challenge studies, the ability of cheese (feta and soft goat’s milk cheese), cold-smoked salmon, coleslaw, and pork pate to support the growth of L. monocytogenes was determined using a starting inoculum of approximately 100 cfu g−1. The cheese and pork pate were incubated at 8 °C for 14 days; the smoked salmon was incubated at 6 °C for 5 days and 8 °C for 9 days; and the coleslaw was incubated at 8 °C for 7 days and 12 °C for 14 days. The results showed that the smoked salmon and pork pate supported growth, while coleslaw and cheese did not. From this study, it is evident that there are factors in food other than pH, water activity, and total bacterial count (TBC) that can inhibit the ability of L. monocytogenes to grow in food.
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