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  1. Article ; Online: Thermal Inactivation of Escherichia Phage OSYSP and Host Strain Escherichia coli O157:H7 EDL933: A Comparative Kinetic Analysis.

    Yesil, Mustafa / Kasler, David R / Huang, En / Yousef, Ahmed E

    Journal of food protection

    2024  Volume 87, Issue 2, Page(s) 100215

    Abstract: Lytic bacteriophages are promising biocontrol agents against pathogenic bacteria for food and therapeutic applications. Investigating the feasibility of combining phage and physical lethal agents, such as heat, as an effective hurdle combination could ... ...

    Abstract Lytic bacteriophages are promising biocontrol agents against pathogenic bacteria for food and therapeutic applications. Investigating the feasibility of combining phage and physical lethal agents, such as heat, as an effective hurdle combination could lead to beneficial applications. The current research was initiated to compare the thermal inactivation kinetics of a lytic phage (Escherichia phage OSYSP) and its host (Shiga toxin-producing Escherichia coli O157:H7 EDL933), considering they have different critical thermal targets in their structures. To provide a basis for comparison, thermal inactivation kinetics were determined on suspensions of these agents in buffered peptone water using a thermally controlled circulating water bath. Results showed that the bacteriophage virions have a remarkable heat resistance (p < 0.05) compared to their host cells. The D-values of the populations of phage (PFU/mL) and EDL933 strain (CFU/mL) were 166.7 and 7.3 min at 55°C, compared to 44.4 and 0.3 min at 60°C, respectively. Additionally, D-values were significantly (p < 0.05) more influenced by temperature changes in the case of E. coli O157:H7 EDL933 (z-value 3.7°C) compared to that for phage OSYSP (z-value 7.7°C). When the phage suspension was heat-treated in a thermal cycler instead of a water bath, no significant differences between the two treatment procedures (p > 0.05) in estimating virus D- and z-values were observed. Based on these findings, it may be feasible to combine phage OSYSP with mild heat during processing of food to selectively inactivate E. coli O157:H7 EDL933 and subsequently maintain product safety during storage by the surviving phage population; however, the feasibility of this application needs to be investigated. Additionally, the relatively heat-resistant phage OSYSP could qualify as a biological indicator to validate thermal treatments of minimally processed foods in which E. coli O157:H7 EDL933 is the pathogen-of-concern.
    MeSH term(s) Bacteriophages/physiology ; Escherichia ; Escherichia coli O157/physiology ; Food Microbiology ; Kinetics ; Water
    Chemical Substances Water (059QF0KO0R)
    Language English
    Publishing date 2024-01-04
    Publishing country United States
    Document type Comparative Study ; Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 243284-5
    ISSN 1944-9097 ; 0362-028X
    ISSN (online) 1944-9097
    ISSN 0362-028X
    DOI 10.1016/j.jfp.2023.100215
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article ; Online: Lytic Escherichia phage OSYSP acts additively and synergistically with gaseous ozone against Escherichia coli O157:H7 on spinach leaves.

    Yesil, Mustafa / Kasler, David R / Huang, En / Yousef, Ahmed E

    Scientific reports

    2023  Volume 13, Issue 1, Page(s) 10706

    Abstract: Bacteriophage and gaseous ozone are evolving as meritorious alternatives to conventional sanitizers in food postharvest applications. Here, we investigated the efficacy of sequential treatments of a lytic bacteriophage and gaseous ozone, during vacuum ... ...

    Abstract Bacteriophage and gaseous ozone are evolving as meritorious alternatives to conventional sanitizers in food postharvest applications. Here, we investigated the efficacy of sequential treatments of a lytic bacteriophage and gaseous ozone, during vacuum cooling of fresh produce, against Escherichia coli O157:H7. Spinach leaves were spot-inoculated with 10
    MeSH term(s) Escherichia coli O157 ; Bacteriophages ; Colony Count, Microbial ; Spinacia oleracea/microbiology ; Food Microbiology ; Escherichia ; Ozone/pharmacology ; Plant Leaves/microbiology
    Chemical Substances Ozone (66H7ZZK23N)
    Language English
    Publishing date 2023-07-03
    Publishing country England
    Document type Journal Article ; Research Support, U.S. Gov't, Non-P.H.S.
    ZDB-ID 2615211-3
    ISSN 2045-2322 ; 2045-2322
    ISSN (online) 2045-2322
    ISSN 2045-2322
    DOI 10.1038/s41598-023-36815-9
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Article: Maximizing Recovery of Paenibacillin, a Bacterially Produced Lantibiotic, Using Continuous Foam Separation from Bioreactors.

    Campbell, Emily P / Kasler, David R / Yousef, Ahmed E

    Foods (Basel, Switzerland)

    2022  Volume 11, Issue 15

    Abstract: Industrial production of paenibacillin, and similar rare antimicrobial peptides, is hampered by low productivity of the producing microorganisms and lack of efficient methods to recover these peptides from fermentor or bioreactor end products. ... ...

    Abstract Industrial production of paenibacillin, and similar rare antimicrobial peptides, is hampered by low productivity of the producing microorganisms and lack of efficient methods to recover these peptides from fermentor or bioreactor end products. Preliminary data showed that paenibacillin was preferentially partitioned in foam accumulated during growth of the producer, Paenibacillus polymyxa, in aerated liquid media. This research was initiated to improve the production and recovery of paenibacillin in bioreactors by maximizing partitioning of this antimicrobial agent in the collected foam. This was completed through harvesting foam continuously during paenibacillin production, using modified bioreactor, and optimizing bioreaction conditions through response surface methodology (RSM). During initial screening, the following factors were tested using 400 mL inoculated media in 2 L bioreactors: medium (tryptic soy broth, TSB, with or without added yeast extract), airflow (0 or 0.8 L/min; LPM), stir speed (300 or 500 revolution/min; RPM), incubation temperature (30 or 36 °C), and incubation time (16 or 24 h). Results showed that airflow, time, and stir speed had significant effects (p < 0.05) on paenibacillin recovery in the collected collapsed foam (foamate). These factors were varied together to follow the path of steepest assent to maximize paenibacillin concentration. Once the local maximum was found, RSM was completed with a central composite design to fine-tune the bioreaction parameters. The optimization experiments proved that the significant parameters and their optimal conditions for paenibacillin concentration in the foam were: incubation at 30 °C for 23 h with airflow of 0.95 LPM, and agitation speed of 450 RPM. These conditions increased paenibacillin concentration, predicted by RSM, from 16 µg/mL in bioreaction without foam collection to 743 µg/mL collected in foamate. The optimized conditions also almost doubled the yield of paenibacillin measured in the foam collected from a bioreaction run (12,674 µg/400 mL bioreaction) when compared to that obtained from a run without foam collection (6400 µg/400 mL bioreaction). Results of this study could improve the feasibility of commercial production and downstream processing of paenibacillin and similar novel antimicrobial peptides. Availability of such peptides will eventually help in protecting perishable products against pathogenic and spoilage bacteria.
    Language English
    Publishing date 2022-07-31
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 2704223-6
    ISSN 2304-8158
    ISSN 2304-8158
    DOI 10.3390/foods11152290
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  4. Article: Removal of

    Tirpanci Sivri, Goksel / Abdelhamid, Ahmed G / Kasler, David R / Yousef, Ahmed E

    Frontiers in microbiology

    2023  Volume 14, Page(s) 1141907

    Abstract: Biofilm formation in food processing environment and within equipment increases the risk of product spoilage and contamination with pathogens. Cleaning-in-place (CIP) operations are useful in removing soils and in sanitizing processing equipment, ... ...

    Abstract Biofilm formation in food processing environment and within equipment increases the risk of product spoilage and contamination with pathogens. Cleaning-in-place (CIP) operations are useful in removing soils and in sanitizing processing equipment, including eliminating biofilms. However, CIP is a resource-intensive process, particularly in the usage of chemical detergents, heat, and sanitizers. The current study was initiated to investigate the feasibility of integrating ozone into CIP operations to facilitate the elimination of
    Language English
    Publishing date 2023-04-14
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 2587354-4
    ISSN 1664-302X
    ISSN 1664-302X
    DOI 10.3389/fmicb.2023.1141907
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  5. Article: Inactivation kinetics of selected pathogenic and non-pathogenic bacteria by aqueous ozone to validate minimum usage in purified water.

    Lou, Yuqian / Kasler, David R / Hawkins, Zach L / Li, Zhen / Sannito, Dan / Fritz, Ronald D / Yousef, Ahmed E

    Frontiers in microbiology

    2024  Volume 14, Page(s) 1258381

    Abstract: Ozone is often used as an antimicrobial agent at the final step in purified water processing. When used in purified bottled water manufacturing, residual ozone should not exceed 0.4 mg/L, per US-FDA regulations. These regulations require the control ... ...

    Abstract Ozone is often used as an antimicrobial agent at the final step in purified water processing. When used in purified bottled water manufacturing, residual ozone should not exceed 0.4 mg/L, per US-FDA regulations. These regulations require the control of
    Language English
    Publishing date 2024-01-15
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 2587354-4
    ISSN 1664-302X
    ISSN 1664-302X
    DOI 10.3389/fmicb.2023.1258381
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  6. Article: Maximizing Recovery of Paenibacillin, a Bacterially Produced Lantibiotic, Using Continuous Foam Separation from Bioreactors

    Campbell, Emily P. / Kasler, David R. / Yousef, Ahmed E.

    Foods. 2022 July 31, v. 11, no. 15

    2022  

    Abstract: Industrial production of paenibacillin, and similar rare antimicrobial peptides, is hampered by low productivity of the producing microorganisms and lack of efficient methods to recover these peptides from fermentor or bioreactor end products. ... ...

    Abstract Industrial production of paenibacillin, and similar rare antimicrobial peptides, is hampered by low productivity of the producing microorganisms and lack of efficient methods to recover these peptides from fermentor or bioreactor end products. Preliminary data showed that paenibacillin was preferentially partitioned in foam accumulated during growth of the producer, Paenibacillus polymyxa, in aerated liquid media. This research was initiated to improve the production and recovery of paenibacillin in bioreactors by maximizing partitioning of this antimicrobial agent in the collected foam. This was completed through harvesting foam continuously during paenibacillin production, using modified bioreactor, and optimizing bioreaction conditions through response surface methodology (RSM). During initial screening, the following factors were tested using 400 mL inoculated media in 2 L bioreactors: medium (tryptic soy broth, TSB, with or without added yeast extract), airflow (0 or 0.8 L/min; LPM), stir speed (300 or 500 revolution/min; RPM), incubation temperature (30 or 36 °C), and incubation time (16 or 24 h). Results showed that airflow, time, and stir speed had significant effects (p < 0.05) on paenibacillin recovery in the collected collapsed foam (foamate). These factors were varied together to follow the path of steepest assent to maximize paenibacillin concentration. Once the local maximum was found, RSM was completed with a central composite design to fine-tune the bioreaction parameters. The optimization experiments proved that the significant parameters and their optimal conditions for paenibacillin concentration in the foam were: incubation at 30 °C for 23 h with airflow of 0.95 LPM, and agitation speed of 450 RPM. These conditions increased paenibacillin concentration, predicted by RSM, from 16 µg/mL in bioreaction without foam collection to 743 µg/mL collected in foamate. The optimized conditions also almost doubled the yield of paenibacillin measured in the foam collected from a bioreaction run (12,674 µg/400 mL bioreaction) when compared to that obtained from a run without foam collection (6400 µg/400 mL bioreaction). Results of this study could improve the feasibility of commercial production and downstream processing of paenibacillin and similar novel antimicrobial peptides. Availability of such peptides will eventually help in protecting perishable products against pathogenic and spoilage bacteria.
    Keywords Paenibacillus polymyxa ; agitation ; air flow ; antimicrobial peptides ; bioreactors ; fermenters ; foams ; lantibiotics ; liquids ; response surface methodology ; spoilage ; temperature ; yeast extract
    Language English
    Dates of publication 2022-0731
    Publishing place Multidisciplinary Digital Publishing Institute
    Document type Article
    ZDB-ID 2704223-6
    ISSN 2304-8158
    ISSN 2304-8158
    DOI 10.3390/foods11152290
    Database NAL-Catalogue (AGRICOLA)

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  7. Article: Effects of frequency on the electrical conductivity of whole shell egg components

    Kasler, David R / Sastry, Sudhir K

    Journal of food process engineering. 2019 June, v. 42, no. 4

    2019  

    Abstract: In an attempt to investigate ohmic heating of shell eggs, the electrical conductivity of its components was determined. Whole shell eggs were split up into five major components including yolk, thin albumen, thick albumen, membrane, and shell. Each was ... ...

    Abstract In an attempt to investigate ohmic heating of shell eggs, the electrical conductivity of its components was determined. Whole shell eggs were split up into five major components including yolk, thin albumen, thick albumen, membrane, and shell. Each was individually tested to determine the effects of electric field frequency and temperature on electrical conductivity. Electrical conductivity of the liquid egg components show results similar to literature values. In the range of frequencies from 10 to 100,000 Hz, little or no frequency dependence was noted for electrical conductivity, with temperature being a far more significant variable. A modeling study for ohmic heating of whole eggs showed significant disagreement with experiment, due principally to inaccuracy in measurement of shell conductivity—accuracy was improved when using an eggshell conductivity that was far lower than the measured value. Nevertheless, despite the lack of significant ohmic heating effects, some current flow within eggs was noted. While data for liquid components may be considered reliable, methods for measuring electrical conductivity of low‐moisture, solid components such as eggshells need to be improved. PRACTICAL APPLICATIONS: We show the effects of frequency on the electrical conductivities of various shell egg components, in particular including the shell and shell membrane, and verify the accuracy of properties data with a heat transfer model. This work is useful for egg industry applications due to recent concerns about contamination with Salmonella, which has prompted research into alternative methods of in‐shell pasteurization of eggs.
    Keywords Salmonella ; egg industry ; egg shell ; eggs ; electric field ; electrical conductivity ; heat transfer ; industrial applications ; liquid egg products ; liquids ; ohmic heating ; pasteurization ; temperature
    Language English
    Dates of publication 2019-06
    Publishing place John Wiley & Sons, Inc.
    Document type Article
    Note JOURNAL ARTICLE
    ZDB-ID 752358-0
    ISSN 0145-8876
    ISSN 0145-8876
    DOI 10.1111/jfpe.13056
    Database NAL-Catalogue (AGRICOLA)

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  8. Article ; Online: Efficacy of Gaseous Ozone Application during Vacuum Cooling against Escherichia coli O157:H7 on Spinach Leaves as Influenced by Bacterium Population Size.

    Yesil, Mustafa / Kasler, David R / Huang, En / Yousef, Ahmed E

    Journal of food protection

    2017  Volume 80, Issue 7, Page(s) 1066–1071

    Abstract: Foodborne disease outbreaks associated with the consumption of fresh produce pose a threat to public health, decrease consumer confidence in minimally processed foods, and negatively impact the sales of these commodities. The aim of the study was to ... ...

    Abstract Foodborne disease outbreaks associated with the consumption of fresh produce pose a threat to public health, decrease consumer confidence in minimally processed foods, and negatively impact the sales of these commodities. The aim of the study was to determine the influence of population size of inoculated pathogen on its inactivation by gaseous ozone treatment during vacuum cooling. Spinach leaves were spot inoculated with Escherichia coli O157:H7 at approximate initial populations of 10
    MeSH term(s) Colony Count, Microbial ; Escherichia coli O157/growth & development ; Food Contamination/prevention & control ; Food Microbiology ; Food Packaging/methods ; Humans ; Ozone ; Population Density ; Spinacia oleracea/microbiology ; Vacuum
    Chemical Substances Ozone (66H7ZZK23N)
    Language English
    Publishing date 2017-04-11
    Publishing country United States
    Document type Journal Article
    ZDB-ID 243284-5
    ISSN 1944-9097 ; 0362-028X
    ISSN (online) 1944-9097
    ISSN 0362-028X
    DOI 10.4315/0362-028X.JFP-16-284
    Database MEDical Literature Analysis and Retrieval System OnLINE

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