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Radiation Resistance and Loss of Crystal Violet Binding Activity in Yersinia enterocolitica Suspended in Raw Ground Pork Exposed to Gamma Radiation and Modified Atmosphere
Author(s) -
Bhaduri Saumya,
Sheen Shiowshuh,
Sommers Christopher H.
Publication year - 2014
Publication title -
journal of food science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.772
H-Index - 150
eISSN - 1750-3841
pISSN - 0022-1147
DOI - 10.1111/1750-3841.12413
Subject(s) - yersinia enterocolitica , crystal violet , virulence , modified atmosphere , microbiology and biotechnology , chemistry , food science , atmosphere (unit) , bacteria , biology , gene , biochemistry , genetics , shelf life , physics , thermodynamics
Virulence of many foodborne pathogens is directly linked to genes carried on self‐replicating extra‐chromosomal elements, which can transfer genetic material, both vertically and horizontally, between bacteria of the same and different species. Pathogenic Yersinia enterocolitica harbors a 70‐kb virulence plasmid (pYV) that encodes genes for low calcium response, crystal violet (CV) binding, Congo red uptake, autoagglutination (AA), hydrophobicity (HP), type III secretion channels, host immune suppression factors, and biofilm formation. Ionizing radiation and modified atmosphere packaging (MAP) are used to control foodborne pathogens and meat spoilage. In this study, the effect of gamma radiation and modified atmosphere (air, 100% N 2 , 75% N 2 : 25% CO 2 , 50% N 2 : 50% CO 2 , 25% N 2 : 75% CO 2 , 100% CO 2 ) were examined by using the CV binding phenotype, for the presence or absence of pYV in Y. enterocolitica , suspended in raw ground pork. All Y. enterocolitica serovars used (O:3, O:8, and O5,27) were more sensitive to radiation as the CO 2 concentration increased above 50%. Crystal violet binding following a radiation dose of 1.0 kGy, which reduced the Y. enterocolitica serovars >5 log, was greatest in the presence of air (ca. 8%), but was not affected by N 2 or CO 2 concentration (ca. 5%). Following release from modified atmosphere after irradiation, the loss of CV binding rose from 5% to 8% immediately following irradiation to >30% after outgrowth at 25 °C for 24 h. These results, using Y. enterocolitica as a model system, indicate that the risk of foodborne illness could be affected by the loss of virulence factors when postprocess intervention technologies are used. Practical Application Provides gamma radiation D 10 data for inactivation data for Y. enterocolitica irradiated under modified atmosphere and information to risk assessors regarding the difference between pathogen presence versus actual virulence.