The commercially available, clear apple juice used as microbial
suspending medium had the following physicochemical characteristics:
pH 3.68, 12.5 Brix. The calculated D values of the E. coli
O157:H7 strains and spoilage yeasts in the UV-C-irradiated and
heated apple juice are presented in Table 1. Based on the D values of
all test organisms, irradiating the test apple juice with UV-C will
require longer processing time to achieve the same lethalities that
resulted from heating the same product at 55 C. Representative
inactivation curves of the individual and composited E. coli
O157:H7 and yeasts in irradiated and heated juices are presented in
Figs. 1 and 2. These curves represent data sets obtained from single
experimental runs. The variations in the data obtained from the
experiments are reflected in the standard deviation values of the
calculated death kinetic parameters presented in Table 1.