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  1. Article ; Online: Barotolerance of Acid-adapted and Cold-adapted Bacterial Isolates of E. coli O157:H7, Salmonella spp., and L. monocytogenes in an Acidic Buffer Model.

    Rolfe, Catherine A / Anderson, Nathan M / Black, Darryl Glenn / Lee, Alvin

    Journal of food protection

    2023  Volume 86, Issue 8, Page(s) 100116

    Abstract: The fruit and vegetable juice industry has shown a growing trend in minimally processed juices. A frequent technology used in the production of functional juices is cold pressure, which refers to the application of high pressure processing (HPP) at low ... ...

    Abstract The fruit and vegetable juice industry has shown a growing trend in minimally processed juices. A frequent technology used in the production of functional juices is cold pressure, which refers to the application of high pressure processing (HPP) at low temperatures to inactivate foodborne pathogens. HPP juice manufacturers are required to demonstrate a 5-log reduction of the pertinent microorganism to comply with FDA Juice HACCP. However, there is no consensus on validation study approaches for bacterial strain selection or their preparation. Individual bacterial strains were grown using three different growth conditions: neutral, cold-adapted, and acid-adapted. Approximately 6.0-7.0 log CFU/mL of the matrix-adapted bacterial strains were inoculated individually into buffered peptone water (BPW) at pH 3.50 ± 0.10 (HCl adjusted) and treated at sublethal pressures of 500 MPa for Escherichia coli O157:H7 and 200 MPa for Salmonella spp. and Listeria monocytogenes (180 s, 4°C). Analyses were conducted at 0, 24, and 48 h (4°C storage) post-HPP on nonselective media. E. coli O157:H7 exhibited greater barotolerance than Salmonella spp. and L. monocytogenes. In neutral growth conditions, E. coli O157:H7 strain TW14359 demonstrated the greatest resistance (2.94 ± 0.64 log reduction), and E. coli O157:H7 strain SEA13B88 was significantly more sensitive (P < 0.05). Salmonella isolates, neutral and acid-adapted, expressed similar barotolerance to one another. Cold-adapted S. Cubana and S. Montevideo showed greater resistance compared to other cold-adapted strains. Acid-adapted L. monocytogenes strain MAD328 had <1.00 ± 0.23 log reduction while acid-adapted L. monocytogenes strains CDC and Scott A were significantly more sensitive (P < 0.05) with reductions of 2.13 ± 0.48 and 3.43 ± 0.50 log CFU/mL, respectively. These results suggested, under the conditions tested, bacterial strain and preparation methods influence HPP efficacy and should be considered when conducting validation studies.
    MeSH term(s) Escherichia coli O157 ; Colony Count, Microbial ; Salmonella ; Fruit ; Listeria monocytogenes ; Food Microbiology
    Language English
    Publishing date 2023-06-13
    Publishing country United States
    Document type Journal Article ; Research Support, U.S. Gov't, P.H.S.
    ZDB-ID 243284-5
    ISSN 1944-9097 ; 0362-028X
    ISSN (online) 1944-9097
    ISSN 0362-028X
    DOI 10.1016/j.jfp.2023.100116
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article: Rapid detection and quantitation of dipicolinic acid from Clostridium botulinum spores using mixed-mode liquid chromatography-tandem mass spectrometry

    Redan, Benjamin W. / Morrissey, Travis R. / Rolfe, Catherine A. / Aguilar, Viviana L. / Skinner, Guy E. / Reddy, N. Rukma

    Analytical and bioanalytical chemistry. 2022 Mar., v. 414, no. 8

    2022  

    Abstract: Analysis of the dipicolinic acid (DPA) released from Clostridium botulinum spores during thermal processing is crucial to obtaining a mechanistic understanding of the factors involved in spore heat resistance and related food safety applications. Here, ... ...

    Abstract Analysis of the dipicolinic acid (DPA) released from Clostridium botulinum spores during thermal processing is crucial to obtaining a mechanistic understanding of the factors involved in spore heat resistance and related food safety applications. Here, we developed a novel mixed-mode liquid chromatography-tandem mass spectrometry (LC–MS/MS) method for detection of the DPA released from C. botulinum type A, nonproteolytic types B and F strains, and nonpathogenic surrogate Clostridium sporogenes PA3679 spores. DPA was retained on a mixed-mode C18/anion exchange column and was detected using electrospray ionization (ESI) positive mode within a 4-min analysis time. The intraday and interday precision (%CV) was 1.94–3.46% and 4.04–8.28%, respectively. Matrix effects were minimal across proteolytic type A Giorgio-A, nonproteolytic types QC-B and 202-F, and C. sporogenes PA3679 spore suspensions (90.1–114% of spiked DPA concentrations). DPA recovery in carrot juice and beef broth ranged from 105 to 118%, indicating limited matrix effects of these food products. Experiments that assessed the DPA released from Giorgio-A spores over the course of a 5-min thermal treatment at 108 °C found a significant correlation (R = 0.907; P < 0.05) between the log reduction of spores and amount of DPA released. This mixed-mode LC–MS/MS method provides a means for rapid detection of DPA released from C. botulinum spores during thermal processing and has the potential to be used for experiments in the field of food safety that assess the thermal resistance characteristics of various C. botulinum spore types.
    Keywords Clostridium botulinum ; Clostridium sporogenes ; analytical chemistry ; beef ; carrot juice ; electrospray ionization mass spectrometry ; food safety ; heat tolerance ; heat treatment ; liquid chromatography ; proteolysis ; rapid methods ; spores ; tandem mass spectrometry
    Language English
    Dates of publication 2022-03
    Size p. 2767-2774.
    Publishing place Springer Berlin Heidelberg
    Document type Article
    ISSN 1618-2642
    DOI 10.1007/s00216-022-03926-7
    Database NAL-Catalogue (AGRICOLA)

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  3. Article ; Online: Rapid detection and quantitation of dipicolinic acid from Clostridium botulinum spores using mixed-mode liquid chromatography-tandem mass spectrometry.

    Redan, Benjamin W / Morrissey, Travis R / Rolfe, Catherine A / Aguilar, Viviana L / Skinner, Guy E / Reddy, N Rukma

    Analytical and bioanalytical chemistry

    2022  Volume 414, Issue 8, Page(s) 2767–2774

    Abstract: Analysis of the dipicolinic acid (DPA) released from Clostridium botulinum spores during thermal processing is crucial to obtaining a mechanistic understanding of the factors involved in spore heat resistance and related food safety applications. Here, ... ...

    Abstract Analysis of the dipicolinic acid (DPA) released from Clostridium botulinum spores during thermal processing is crucial to obtaining a mechanistic understanding of the factors involved in spore heat resistance and related food safety applications. Here, we developed a novel mixed-mode liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for detection of the DPA released from C. botulinum type A, nonproteolytic types B and F strains, and nonpathogenic surrogate Clostridium sporogenes PA3679 spores. DPA was retained on a mixed-mode C18/anion exchange column and was detected using electrospray ionization (ESI) positive mode within a 4-min analysis time. The intraday and interday precision (%CV) was 1.94-3.46% and 4.04-8.28%, respectively. Matrix effects were minimal across proteolytic type A Giorgio-A, nonproteolytic types QC-B and 202-F, and C. sporogenes PA3679 spore suspensions (90.1-114% of spiked DPA concentrations). DPA recovery in carrot juice and beef broth ranged from 105 to 118%, indicating limited matrix effects of these food products. Experiments that assessed the DPA released from Giorgio-A spores over the course of a 5-min thermal treatment at 108 °C found a significant correlation (R = 0.907; P < 0.05) between the log reduction of spores and amount of DPA released. This mixed-mode LC-MS/MS method provides a means for rapid detection of DPA released from C. botulinum spores during thermal processing and has the potential to be used for experiments in the field of food safety that assess the thermal resistance characteristics of various C. botulinum spore types.
    MeSH term(s) Chromatography, Liquid ; Clostridium botulinum/chemistry ; Hot Temperature ; Picolinic Acids/analysis ; Spores, Bacterial/chemistry ; Tandem Mass Spectrometry
    Chemical Substances Picolinic Acids ; dipicolinic acid (UE81S5CQ0G)
    Language English
    Publishing date 2022-02-02
    Publishing country Germany
    Document type Journal Article
    ZDB-ID 201093-8
    ISSN 1618-2650 ; 0016-1152 ; 0372-7920
    ISSN (online) 1618-2650
    ISSN 0016-1152 ; 0372-7920
    DOI 10.1007/s00216-022-03926-7
    Database MEDical Literature Analysis and Retrieval System OnLINE

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