Analysis and modeling of the variability associated with UV inactivation of Escherichia coli in apple cider

Abstract

Raw data from validation studies of UV tubes used for nonthermal pathogen reduction in apple cider underwent comprehensive statistical analysis. Data from each tube that demonstrated at least a 5-log reduction of Escherichia coli ATCC 25922, a surrogate for E. coli O157:H7, in each of three trials were used in the analysis. The within- and between-tube variability was calculated for 70 tubes. The mean log reductions of the tubes fit a Beta distribution (Kolmogorov-Smirnov test, 0.0246), and the between-replicate variability followed a logistic distribution (Kolmogorov-Smirnov test, 0.0305). These two distributions can be used together to model UV cider treatment as part of an overall E. coli O157:H7 in cider risk assessment. Examples of codes from ®ISK and Analytica to describe these distributions, such as one would find in a quantitative risk assessment, are included.