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MATHEMATICAL MODEL FOR THE SURVIVAL OF LISTERIA MONOCYTOGENES IN MEXICAN-STYLE SAUSAGE

Authors

  • M.N. HAJMEER,

    Corresponding author
    1. Department of Population Health and Reproduction
      School of Veterinary Medicine
      University of California
      Davis, CA 95616-8743
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  • I.A. BASHEER,

    1. Office of Infrastructure Research & Development
      Turner-Fairbank Highway Research Center
      Federal Highway Administration, 6300 Georgetown Pike
      McLean, VA 22101-2296
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  • D.O. CLIVER

    1. Department of Population Health and Reproduction
      School of Veterinary Medicine
      University of California
      Davis, CA 95616-8743
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TEL: (530) 754-7373; FAX: (530) 752-5845; EMAIL: mnhajmeer@ucdavis.edu

ABSTRACT

Survival of Listeria monocytogenes in chorizos (Mexican-style sausages) was modeled in relation to initial water activity (aw0) and storage conditions using the Weibull cumulative distribution function. Twenty survival curves were generated from chorizos formulated at aw0 = 0.85–0.97 then stored under four temperature (T) and air inflow velocity (F) conditions. The Weibull model parameters (α and β) were determined for every curve. Predicted survival curves agreed with experimental curves with R2 = 0.945–0.992. Regression models (R2 = 0.981–0.984) were developed to relate α and β to operating conditions. The times to one- and two-log reduction in count (t1D and t2D) were derived from the Weibull model in terms of α and β. A parametric study revealed that L. monocytogenes survival was most sensitive to aw0 between 0.90 and 0.95. The inactivation of L. monocytogenes could be maximized with higher T and lower aw0; however, F did not significantly influence survival.

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