MODELING THE INACTIVATION OF ESCHERICHIA COLI O157:H7 ON INOCULATED ALFALFA SEEDS DURING EXPOSURE TO OZONATED OR ELECTROLYZED OXIDIZING WATER
Alfalfa sprouts contaminated with Escherichia coli O157:H7 and Salmonella have been implicated in a number 
of foodborne disease outbreaks in recent years. Seeds are attributed to be the main source of contamination for sprouts. Data 
from studies on the treatment of E. coli O157:H7 inoculated alfalfa seeds with ozonated and electrolyzed oxidizing (EO) water 
were used to develop models for predicting inactivation of the pathogen. Treatment times of 0 to 16 min were used for ozonated 
water at initial concentrations of 0 to 21 ppm. For EO water treatments, 0 to 19 amperage (A) data at treatment times of 0 to 
32 min were used to develop the models. A modified Monod model for bacterial death kinetics was developed by integrating 
the rate constant (k) as a Lorentzian function of treatment time (t). Regression constants for the Lorentzian function were 
determined at various ozone concentrations (ppm) or A. Validation showed that the model was an effective predictor at ozone 
concentrations below 8 ppm. As a second method, a response surface model (RSM) was utilized for which an RSM regression 
was performed between observed log10N/No and ppm (ozone) or A (EO water) and treatment time. A quadratic equation 
involving linear, quadratic, and interaction terms of the influencing parameters represented the model for ozonated and EO 
water treatments. The models were validated by back predicting log10N/No values. Although numerous other factors influence 
the accuracy of prediction of the models, these models can be useful tools to researchers and regulators for the development 
of improved seed sanitizing guidelines by facilitating assessment of efficacy of a treatment and enhancing food safety.