Inactivation of Escherichia Coli O157 On Inoculated Alfalfa Seeds with Pulsed Ultraviolet Light and Response Surface Modeling

Inactivation of Escherichia coli O157:H7 on Inoculated Alfalfa Seeds with Pulsed Ultraviolet Light and Response Surface Modeling

R.R. Sharma and A. Demirci

J. of Food Sci., Vol. 68, No. 4, 2003

ABSTRACT:
Escherichia coli O157:H7-inoculated alfalfa seeds with seed layer thicknesses of 1.02 to 6.25 mm were subjected to pulsed UV light for up to 90 s at a 8-cm distance from the UV strobe. Population reductions higher than 4 log10 colony-forming units (CFU)/g were achieved. For effect of distance from the UV strobe, seeds with 6.25-mm layer thickness were treated 3 to 13 cm from the strobe. Reductions at shorter distances, such as 60 s at 5 cm (1.93 log10 CFU/g) and 60 to 90 s at 8 cm (4.89 log10 CFU/g), were significantly higher (P # 0.05). Data from the treatments were used to develop empirical models as a function of distance or layer thickness and treatment time for predicting the population ofE. coli O157:H7 during pulsed UV-light treatment. This study demonstrates that pulsed UV light holds promise for eliminating pathogens from alfalfa seeds, and the models developed can be useful predictive tools.