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Lei Wang - One of the best experts on this subject based on the ideXlab platform.

  • structure and genetics of the o antigen of Cronobacter Sakazakii g2726 serotype o3 closely related to the o antigen of c muytjensii 3270
    Carbohydrate Research, 2012
    Co-Authors: Nikolay P Arbatsky, Alexander S Shashkov, Lei Wang, Yamin Sun, Min Wang, Bin Liu, Elena D Daeva, Yuriy A. Knirel
    Abstract:

    Abstract The O-specific polysaccharide (O-antigen) was isolated from the lipopolysaccharide of Cronobacter Sakazakii G2726 (serotype O3) and studied by sugar analysis, Smith degradation, and 1 H and 13 C NMR spectroscopy. The following structure of the acidic O-polysaccharide was established: Download full-size image This structure is closely related to that of the O-polysaccharide of Cronobacter muytjensii 3270, which has the same main chain and differs only in the lack of glucosylation. The O-antigen gene cluster of C. Sakazakii G2726 found between the gnd and galF genes was sequenced, and the gene functions were tentatively assigned by similarity to related genes from available databases and taking into account the O-polysaccharide structure.

  • development of an o antigen serotyping scheme for Cronobacter Sakazakii
    Applied and Environmental Microbiology, 2011
    Co-Authors: Yamin Sun, Min Wang, Hongbo Liu, Jingjing Wang, Jing Zeng, Xi Guo, Boyang Cao, Lei Wang
    Abstract:

    Cronobacter Sakazakii is an opportunistic pathogen that can cause severe infections. Serotyping provides a basis for the categorization of bacterial strains and is an important tool for epidemiological and surveillance purposes. In this study, of the 135 Cronobacter strains tested initially, 119 were identified as C. Sakazakii and used. A serotyping scheme for C. Sakazakii that classifies strains based on their different O antigens was developed. Seven antisera that exhibited high agglutinin titers (>640) were produced. O2 and O6 antisera were specific for their homologous strains, O4 and O7 antisera gave heterologous titers with O1 and O6 antigens, respectively, and O1, O3, and O5 antisera cross-reacted with each other and require preabsorption with the other two antigens. All of these 119 C. Sakazakii strains were clearly assigned to these seven serotypes. O1 and O2 are the dominant serotypes, comprising 69.7% of the isolates. We also characterized the O-antigen gene clusters using restriction fragment length polymorphism (RFLP). The grouping of C. Sakazakii strains based on their RFLP banding patterns correlated well with the grouping of strains based on our serotyping scheme. The serotype scheme presented here could prove to be a useful tool for serotyping C. Sakazakii isolates.

  • structure of the o polysaccharide of Cronobacter Sakazakii o2 with a randomly o acetylated l rhamnose residue
    Carbohydrate Research, 2010
    Co-Authors: Nikolay P Arbatsky, Yuriy A. Knirel, Alexander S Shashkov, Min Wang, Alexander O Chizhov, Lu Feng, Lei Wang
    Abstract:

    Abstract Studies by sugar analysis and partial acid hydrolysis along with one- and two-dimensional 1 H and 13 C NMR spectroscopy and high-resolution ESI MS showed that the O-polysaccharide (O-antigen) Cronobacter Sakazakii ATCC 29004 (serotype O2) possesses a branched hexasaccharide O-unit with a randomly mono-O-acetylated terminal rhamnose residue in the side chain and the following structure: A similar structure has been reported for the O-polysaccharide of C. Sakazakii 767, which differs in the presence of an additional lateral α- d -Glc p residue on GlcNAc and the pattern of O-acetylation (Czerwicka, M., Forsythe, S. J.; Bychowska, A.; Dziadziuszko, H.; Kunikowska, D.; Stepnowski, P.; Kaczynski, Z. Carbohydr. Res. 2010 , 345 , 908–913).

  • structure of the o polysaccharide of Cronobacter Sakazakii o1 containing 3 n acetyl l alanyl amino 3 6 dideoxy d glucose
    Carbohydrate Research, 2010
    Co-Authors: Nikolay P Arbatsky, Yuriy A. Knirel, Alexander S Shashkov, Min Wang, Lu Feng, Lei Wang
    Abstract:

    Abstract The O-polysaccharide (O-antigen) was released by mild acid hydrolysis of the lipopolysaccharide of Cronobacter Sakazakii ATCC 29544T (serotype O1) and studied by composition analysis and Smith degradation, in addition to 1D and 2D 1H and 13C NMR spectroscopy. The following structure of the pentasaccharide repeating unit of the O-polysaccharide was established: Download : Download full-size image where d -Qui3NAcyl stands for 3-(N-acetyl- l -alanyl)amino-3,6-dideoxy- d -glucose. The same composition but a different structure has been reported earlier for the O-polysaccharide of C. Sakazakii 3290 [MacLean, L. L.; Pagotto, F.; Farber, J. M.; Perry, M. B. Biochem. Cell Biol.2009, 87, 459–465].

  • structure of the o polysaccharide of Cronobacter Sakazakii o1 containing 3 n acetyl l alanyl amino 3 6 dideoxy d glucose
    Carbohydrate Research, 2010
    Co-Authors: Nikolay P Arbatsky, Yuriy A. Knirel, Alexander S Shashkov, Min Wang, Lu Feng, Lei Wang
    Abstract:

    The O-polysaccharide (O-antigen) was released by mild acid hydrolysis of the lipopolysaccharide of Cronobacter Sakazakii ATCC 29544(T) (serotype O1) and studied by composition analysis and Smith degradation, in addition to 1D and 2D (1)H and (13)C NMR spectroscopy. The following structure of the pentasaccharide repeating unit of the O-polysaccharide was established: [Formula: see text] where d-Qui3NAcyl stands for 3-(N-acetyl-l-alanyl)amino-3,6-dideoxy-d-glucose. The same composition but a different structure has been reported earlier for the O-polysaccharide of C. Sakazakii 3290 [MacLean, L. L.; Pagotto, F.; Farber, J. M.; Perry, M. B. Biochem. Cell Biol.2009, 87, 459-465].

Nikolay P Arbatsky - One of the best experts on this subject based on the ideXlab platform.

  • structure and genetics of the o antigen of Cronobacter Sakazakii g2726 serotype o3 closely related to the o antigen of c muytjensii 3270
    Carbohydrate Research, 2012
    Co-Authors: Nikolay P Arbatsky, Alexander S Shashkov, Lei Wang, Yamin Sun, Min Wang, Bin Liu, Elena D Daeva, Yuriy A. Knirel
    Abstract:

    Abstract The O-specific polysaccharide (O-antigen) was isolated from the lipopolysaccharide of Cronobacter Sakazakii G2726 (serotype O3) and studied by sugar analysis, Smith degradation, and 1 H and 13 C NMR spectroscopy. The following structure of the acidic O-polysaccharide was established: Download full-size image This structure is closely related to that of the O-polysaccharide of Cronobacter muytjensii 3270, which has the same main chain and differs only in the lack of glucosylation. The O-antigen gene cluster of C. Sakazakii G2726 found between the gnd and galF genes was sequenced, and the gene functions were tentatively assigned by similarity to related genes from available databases and taking into account the O-polysaccharide structure.

  • structure of the o polysaccharide of Cronobacter Sakazakii o2 with a randomly o acetylated l rhamnose residue
    Carbohydrate Research, 2010
    Co-Authors: Nikolay P Arbatsky, Yuriy A. Knirel, Alexander S Shashkov, Min Wang, Alexander O Chizhov, Lu Feng, Lei Wang
    Abstract:

    Abstract Studies by sugar analysis and partial acid hydrolysis along with one- and two-dimensional 1 H and 13 C NMR spectroscopy and high-resolution ESI MS showed that the O-polysaccharide (O-antigen) Cronobacter Sakazakii ATCC 29004 (serotype O2) possesses a branched hexasaccharide O-unit with a randomly mono-O-acetylated terminal rhamnose residue in the side chain and the following structure: A similar structure has been reported for the O-polysaccharide of C. Sakazakii 767, which differs in the presence of an additional lateral α- d -Glc p residue on GlcNAc and the pattern of O-acetylation (Czerwicka, M., Forsythe, S. J.; Bychowska, A.; Dziadziuszko, H.; Kunikowska, D.; Stepnowski, P.; Kaczynski, Z. Carbohydr. Res. 2010 , 345 , 908–913).

  • structure of the o polysaccharide of Cronobacter Sakazakii o1 containing 3 n acetyl l alanyl amino 3 6 dideoxy d glucose
    Carbohydrate Research, 2010
    Co-Authors: Nikolay P Arbatsky, Yuriy A. Knirel, Alexander S Shashkov, Min Wang, Lu Feng, Lei Wang
    Abstract:

    Abstract The O-polysaccharide (O-antigen) was released by mild acid hydrolysis of the lipopolysaccharide of Cronobacter Sakazakii ATCC 29544T (serotype O1) and studied by composition analysis and Smith degradation, in addition to 1D and 2D 1H and 13C NMR spectroscopy. The following structure of the pentasaccharide repeating unit of the O-polysaccharide was established: Download : Download full-size image where d -Qui3NAcyl stands for 3-(N-acetyl- l -alanyl)amino-3,6-dideoxy- d -glucose. The same composition but a different structure has been reported earlier for the O-polysaccharide of C. Sakazakii 3290 [MacLean, L. L.; Pagotto, F.; Farber, J. M.; Perry, M. B. Biochem. Cell Biol.2009, 87, 459–465].

  • structure of the o polysaccharide of Cronobacter Sakazakii o1 containing 3 n acetyl l alanyl amino 3 6 dideoxy d glucose
    Carbohydrate Research, 2010
    Co-Authors: Nikolay P Arbatsky, Yuriy A. Knirel, Alexander S Shashkov, Min Wang, Lu Feng, Lei Wang
    Abstract:

    The O-polysaccharide (O-antigen) was released by mild acid hydrolysis of the lipopolysaccharide of Cronobacter Sakazakii ATCC 29544(T) (serotype O1) and studied by composition analysis and Smith degradation, in addition to 1D and 2D (1)H and (13)C NMR spectroscopy. The following structure of the pentasaccharide repeating unit of the O-polysaccharide was established: [Formula: see text] where d-Qui3NAcyl stands for 3-(N-acetyl-l-alanyl)amino-3,6-dideoxy-d-glucose. The same composition but a different structure has been reported earlier for the O-polysaccharide of C. Sakazakii 3290 [MacLean, L. L.; Pagotto, F.; Farber, J. M.; Perry, M. B. Biochem. Cell Biol.2009, 87, 459-465].

Min Wang - One of the best experts on this subject based on the ideXlab platform.

  • genomics and experimental analysis reveal a novel factor contributing to the virulence of Cronobacter Sakazakii strains associated with neonate infection
    The Journal of Infectious Diseases, 2019
    Co-Authors: Min Wang, Lu Wang, Tingting Chen, Yiming Zhu, Yang Zhang, Yi Wei
    Abstract:

    Background Cronobacter Sakazakii causes meningitis and necrotizing enterocolitis in premature infants. However, its virulence determinants, especially those specific for strains associated with neonate infections, remain largely unknown. Methods In this study, we performed a comparative genomic analysis of 209 C. Sakazakii genomes, and 8 clonal groups (CGs) were revealed. Results CG1 and CG2 were found to be significantly associated with neonate infections, and significantly prevalent genes in these 2 CGs were identified. Of these, a gene encoding the LysR-type regulator, CklR, was shown to contribute to bacterial pathogenicity based on animal experiments. We found that CklR directly binds and activates the suf Fe-S cluster biosynthesis operon, and high expression of the suf operon increases bacterial resistance to oxidative stress, which increases survival within the host. This leads to a high degree of bacteremia, which contributes to the development of meningitis. Conclusions Our work revealed a novel virulence factor specific to predominant pathogenic C. Sakazakii strains.

  • Table_1_The Roles of Two Type VI Secretion Systems in Cronobacter Sakazakii ATCC 12868.docx
    2018
    Co-Authors: Min Wang, Xi Guo, Hengchun Cao, Qian Wang, Bin Liu
    Abstract:

    The type VI secretion system (T6SS), which has been found in 25% of gram-negative bacteria, is a crucial virulence factor in several pathogens. Although T6SS gene loci have been discovered in Cronobacter species, one of the major opportunistic foodborne pathogens, its function has not been elucidated. In this study, the roles of two phylogenetically distinct T6SS gene clusters in Cronobacter Sakazakii ATCC12868 were investigated. Analysis of 138 genome sequences of C. Sakazakii strains, we found that one T6SS gene cluster (T6SS-1) was ubiquitous in all examined strains, whereas another (T6SS-2) was absent or degenerated in a large proportion of the strains (n = 97). In addition, we confirmed the T6SS-1 antibacterial function through an in-frame deletion in the vasK and hcp genes. Compared with the wild-type strain, the T6SS-2-deficient mutant presented a much stronger colonization of organs when infecting neonatal rats. Thus, we proposed that T6SS-2 plays a role in pathogenic processes. This is the first study to investigate the functions of T6SS in C. Sakazakii, and the results will extend our understanding of the pathogenic and phylogenetic characteristics of C. Sakazakii.

  • Image_4_The Roles of Two Type VI Secretion Systems in Cronobacter Sakazakii ATCC 12868.TIF
    2018
    Co-Authors: Min Wang, Xi Guo, Hengchun Cao, Qian Wang, Bin Liu
    Abstract:

    The type VI secretion system (T6SS), which has been found in 25% of gram-negative bacteria, is a crucial virulence factor in several pathogens. Although T6SS gene loci have been discovered in Cronobacter species, one of the major opportunistic foodborne pathogens, its function has not been elucidated. In this study, the roles of two phylogenetically distinct T6SS gene clusters in Cronobacter Sakazakii ATCC12868 were investigated. Analysis of 138 genome sequences of C. Sakazakii strains, we found that one T6SS gene cluster (T6SS-1) was ubiquitous in all examined strains, whereas another (T6SS-2) was absent or degenerated in a large proportion of the strains (n = 97). In addition, we confirmed the T6SS-1 antibacterial function through an in-frame deletion in the vasK and hcp genes. Compared with the wild-type strain, the T6SS-2-deficient mutant presented a much stronger colonization of organs when infecting neonatal rats. Thus, we proposed that T6SS-2 plays a role in pathogenic processes. This is the first study to investigate the functions of T6SS in C. Sakazakii, and the results will extend our understanding of the pathogenic and phylogenetic characteristics of C. Sakazakii.

  • structure and genetics of the o antigen of Cronobacter Sakazakii g2726 serotype o3 closely related to the o antigen of c muytjensii 3270
    Carbohydrate Research, 2012
    Co-Authors: Nikolay P Arbatsky, Alexander S Shashkov, Lei Wang, Yamin Sun, Min Wang, Bin Liu, Elena D Daeva, Yuriy A. Knirel
    Abstract:

    Abstract The O-specific polysaccharide (O-antigen) was isolated from the lipopolysaccharide of Cronobacter Sakazakii G2726 (serotype O3) and studied by sugar analysis, Smith degradation, and 1 H and 13 C NMR spectroscopy. The following structure of the acidic O-polysaccharide was established: Download full-size image This structure is closely related to that of the O-polysaccharide of Cronobacter muytjensii 3270, which has the same main chain and differs only in the lack of glucosylation. The O-antigen gene cluster of C. Sakazakii G2726 found between the gnd and galF genes was sequenced, and the gene functions were tentatively assigned by similarity to related genes from available databases and taking into account the O-polysaccharide structure.

  • development of an o antigen serotyping scheme for Cronobacter Sakazakii
    Applied and Environmental Microbiology, 2011
    Co-Authors: Yamin Sun, Min Wang, Hongbo Liu, Jingjing Wang, Jing Zeng, Xi Guo, Boyang Cao, Lei Wang
    Abstract:

    Cronobacter Sakazakii is an opportunistic pathogen that can cause severe infections. Serotyping provides a basis for the categorization of bacterial strains and is an important tool for epidemiological and surveillance purposes. In this study, of the 135 Cronobacter strains tested initially, 119 were identified as C. Sakazakii and used. A serotyping scheme for C. Sakazakii that classifies strains based on their different O antigens was developed. Seven antisera that exhibited high agglutinin titers (>640) were produced. O2 and O6 antisera were specific for their homologous strains, O4 and O7 antisera gave heterologous titers with O1 and O6 antigens, respectively, and O1, O3, and O5 antisera cross-reacted with each other and require preabsorption with the other two antigens. All of these 119 C. Sakazakii strains were clearly assigned to these seven serotypes. O1 and O2 are the dominant serotypes, comprising 69.7% of the isolates. We also characterized the O-antigen gene clusters using restriction fragment length polymorphism (RFLP). The grouping of C. Sakazakii strains based on their RFLP banding patterns correlated well with the grouping of strains based on our serotyping scheme. The serotype scheme presented here could prove to be a useful tool for serotyping C. Sakazakii isolates.

Stephen J. Forsythe - One of the best experts on this subject based on the ideXlab platform.

  • Multicenter Study of Cronobacter Sakazakii Infections in Humans, Europe, 2017
    Emerging infectious diseases, 2019
    Co-Authors: Sarah Lepuschitz, Stephen J. Forsythe, Werner Ruppitsch, Shiva Pekard-amenitsch, Martin Cormican, Robert L. Mach, Denis Pierard, Franz Allerberger
    Abstract:

    Cronobacter Sakazakii has been documented as a cause of life-threating infections, predominantly in neonates. We conducted a multicenter study to assess the occurrence of C. Sakazakii across Europe and the extent of clonality for outbreak detection. National coordinators representing 24 countries in Europe were requested to submit all human C. Sakazakii isolates collected during 2017 to a study center in Austria. Testing at the center included species identification by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, subtyping by whole-genome sequencing (WGS), and determination of antimicrobial resistance. Eleven countries sent 77 isolates, including 36 isolates from 2017 and 41 historical isolates. Fifty-nine isolates were confirmed as C. Sakazakii by WGS, highlighting the challenge of correctly identifying Cronobacter spp. WGS-based typing revealed high strain diversity, indicating absence of multinational outbreaks in 2017, but identified 4 previously unpublished historical outbreaks. WGS is the recommended method for accurate identification, typing, and detection of this pathogen.

  • Fatal Cronobacter Sakazakii Sequence Type 494 Meningitis in a Newborn, Brazil.
    Emerging infectious diseases, 2018
    Co-Authors: Cláudia Elizabeth Volpe Chaves, Stephen J. Forsythe, Marcelo Luiz Lima Brandão, Mara Luci Gonçalves Galiz Lacerda, Caroline Aparecida Barbosa Coelho Rocha, Sandra Maria Do Valle Leone De Oliveira, Tânia Cristina Parpinelli, Luiza Vasconcellos, Anamaria Mello Miranda Paniago
    Abstract:

    We describe a case of infection with Cronobacter Sakazakii sequence type 494 causing bacteremia and meningitis in a hospitalized late premature infant in Brazil. We conducted microbiological analyses on samples of powdered infant formula from the same batch as formula ingested by the infant but could not identify the source of contamination.

  • reevaluation of a suspected Cronobacter Sakazakii outbreak in mexico
    Journal of Food Protection, 2015
    Co-Authors: Emily E Jackson, Julio Parra Flores, Eduardo Fernandezescartin, Stephen J. Forsythe
    Abstract:

    In 2010, two infants became ill at a hospital in Mexico. Subsequently, a range of clinical, environmental, and powdered and rehydrated infant formula isolates were identified by using a combination of phenotyping and PCR probes. The strains were clustered according to pulsed-field gel electrophoresis. The causative agent was reported as Cronobacter Sakazakii, with powdered infant formula (PIF) identified as the likely source of the infections. This new study further characterized the isolates from this outbreak by using multilocus sequence typing and whole genome sequencing of selected strains. Though four PIF isolates and one hospital environmental isolate were identified as C. Sakazakii sequence type 297 by multilocus sequence typing, they were isolated 6 months prior to the outbreak. Genotypic analyses of patient isolates identified them as Enterobacter hormaechei and Enterobacter spp. The pulsed-field gel electrophoresis profile of the Enterobacter spp. isolates matched those of isolates from previous...

  • predominance of Cronobacter Sakazakii sequence type 4 in neonatal infections
    Emerging Infectious Diseases, 2011
    Co-Authors: Susan Joseph, Stephen J. Forsythe
    Abstract:

    A 7-loci (3,036 nt) multilocus sequence typing scheme was applied to 41 clinical isolates of Cronobacter Sakazakii. Half (20/41) of the C. Sakazakii strains were sequence type (ST) 4, and 9/12 meningitis isolates were ST4. C. Sakazakii ST4 appears to be a highly stable clone with a high propensity for neonatal meningitis.

  • structure of the o polysaccharide isolated from Cronobacter Sakazakii 767
    Carbohydrate Research, 2010
    Co-Authors: Malgorzata Czerwicka, Stephen J. Forsythe, Anna Bychowska, Halina Dziadziuszko, Danuta Kunikowska, Piotr Stepnowski, Zbigniew Kaczynski
    Abstract:

    Abstract The Cronobacter spp., previously known as Enterobacter Sakazakii , are Gram-negative enterobacterial pathogens that can cause necrotizing enterocolitis, meningitis, and septicemia with a high mortality rate in neonates. The O-specific polysaccharide (O-PS) was isolated from Cronobacter Sakazakii strain 767 and structurally characterized using 1 H and 13 C NMR spectroscopy, including two-dimensional DQF-COSY, TOCSY, ROESY, HSQC, and HMBC experiments. Further compositional determination was undertaken using classical chemical methods followed by GLC, and GLC–MS analysis. The repeating unit of O-PS isolated from C. Sakazakii 767 was a branched heptasaccharide composed of l -Rha, d -Glc, d -GlcNAc, and d -GalA, and had the structure shown below. One of the Rha residues was partially O-acetylated at C-4. C. Sakazakii 767 was originally isolated from a fatal neonatal meningitic case, and the structure of its O-PS significantly differs from the O-PS structures previously described for Cronobacter spp. Download full-size image

Dongjie Chen - One of the best experts on this subject based on the ideXlab platform.

  • catalytic intense pulse light inactivation of Cronobacter Sakazakii and other pathogens in non fat dry milk and wheat flour
    Food Chemistry, 2020
    Co-Authors: Dongjie Chen, Justin Wiertzema, Yunpu Wang, Yanling Cheng, Peng Peng, Juer Liu, Wes Mosher, Myungwoo Kang, Min Min, Paul Chen
    Abstract:

    Abstract The outbreaks of Cronobacter Sakazakii, Salmonella spp, and Bacillus cereus in powdered foods have been increasing in worldwide. However, an effective method to pasteurize powdered foods before consumption remains lacking. A prototype Intense Pulsed Light (IPL) system was developed to disinfect powdered foods under different IPL and environmental conditions. Synergistic effect of IPL and TiO2 photocatalysis on microbial inactivation was studied. The results show that high energy intensity of each pulse, high peak intensity, and short pulsed duration contributed to a high microbe inactivation. With TiO2 photocatalysis, one additional log10 reduction was achieved, bringing the total log reduction to 4.71 ± 0.07 (C. Sakazakii), 3.49 ± 0.01 (E. faecium), and 2.52 ± 0.10 (B. cereus) in non-fat dry milk, and 5.42 ± 0.10 (C. Sakazakii), 4.95 ± 0.24 (E. faecium), 2.80 ± 0.23 (B. cereus) in wheat flour. IPL treatment combined with the TiO2 photocatalysis exhibits a strong potential to reduce the energy consumption in improving the safety of powdered foods.

  • evaluation of Cronobacter Sakazakii inactivation and physicochemical property changes of non fat dry milk powder by cold atmospheric plasma
    Food Chemistry, 2019
    Co-Authors: Dongjie Chen, Paul Chen, Yanling Cheng, Nan Zhou, Peng Peng, Chi Chen, Roger Ruan
    Abstract:

    Abstract Cronobacter Sakazakii can cause life-threatening infections in neonates. Exposure to contaminated powdered food, especially milk powder, is a major route for C. Sakazakii infection. Cold atmospheric plasma (CAP) is well known as a non-thermal method for inactivating microbial pathogens. This study evaluates the effectiveness of CAP on C. Sakazakii in non-fat dry milk (NFDM) powder using a fluidized reaction system. The CAP treatments for 20–120 s led to 1.17–3.27 log10 reductions of C. Sakazakii. C. Sakazakii inactivation increased with increasing flow rate from 8 to 20 L/min. In terms of quality attributes of NFDM after the CAP treatments, no noticeable color changes (ΔE

  • Effects of intense pulsed light on Cronobacter Sakazakii and Salmonella surrogate Enterococcus faecium inoculated in different powdered foods
    Food Chemistry, 2019
    Co-Authors: Dongjie Chen, Yiwei Ma, Erik Anderson, Yunpu Wang, Paul Chen, Yanling Cheng, Peng Peng, Chi Chen, Roger Ruan
    Abstract:

    Abstract Cronobacter Sakazakii and Salmonella spp. are foodborne pathogens associated with low moisture foods. An intense pulsed light (IPL) system is being developed as an alternative novel method to pasteurize powdered food. The aim of the study is to investigate the microorganism inactivation in different powdered foods and a variety of related variables using a vibratory-assisted IPL system. The results showed that C. Sakazakii on non-fat dry milk (NFDM), wheat flour, and egg white powder were significantly inactivated by 5.27, 4.92, and 5.30 log10 CFU/g, respectively, after 3 or 4 passes of IPL treatments. For decontamination of E. faecium, 3–4 passes of IPL treatments reduced the E. faecium level on NFDM, wheat flour, and egg white by 3.67, 2.79, 2.74 log10 CFU/g, respectively. These results demonstrated that the enhanced microbiological inactivation can be achieved using this vibratory-assisted IPL system after multiple passes.

  • Effects of intense pulsed light on Cronobacter Sakazakii inoculated in non-fat dry milk
    Journal of Food Engineering, 2018
    Co-Authors: Dongjie Chen, Justin Wiertzema, Yiwei Ma, Erik Anderson, Paul Chen, Yanling Cheng, Peng Peng, David J. Baumler
    Abstract:

    Abstract Cronobacter Sakazakii is known to have caused life-threatening infections in neonates with a fatality rate of 40–80%. Contaminated powdered food, especially powdered infant formula (PIF), has been epidemiologically linked with these foodborne outbreak infections. Clinical symptoms of C. Sakazakii infection include necrotizing enterocolitis, bacteremia, and meningitis. Traditional thermal processing of PIF has been used to kill foodborne pathogens, but it has an undesirable flavor and quality attributes that are unacceptable for industrial usage. Thus, there is a need for new bactericidal technologies for dry powdered foods. In this study, an intense pulsed light (IPL) treatment system was developed, and processing parameters such as relative humidity, environmental temperature, initial water activity, initial temperature, and residence time were evaluated for a bactericidal effect on C. Sakazakii in non-fat dry milk (NFDM). The results indicated that a synergistic effect of IPL and an appropriate temperature of ∼57.5 ± 0.7 °C exhibited maximum inactivation of 3.18 log10 CFU/g for C. Sakazakii in NFDM with little agglomeration at the initial temperature of 25 °C, at the water activity level of 0.25, and a residence time of 28 s. In addition, significantly higher inactivation was observed when IPL was combined with a vibratory feeder (p