Combined treatment of fumaric acid with aqueous chlorine dioxide or UV-C irradiation to inactivate Escherichia coli O157:H7, Salmonella enterica serovar Typhimurium, and Listeria monocytogenes inoculated on alfalfa and clover sprouts

Effect of fumaric acid, chlorine dioxide (ClO2), and UV-C treatment was examined on the inactivation of microorganisms in alfalfa and clover sprouts. Clover sprouts were irradiated with UV-C light (1-10 kJ/m(2)), and the treatment decreased the population of total aerobic bacteria by 1.03-1.45 log CFU/g. Clover sprouts inoculated with pathogenic bacteria were treated with various concentration of fumaric acid, and 0.5 g/100 ml fumaric acid treatment was the most effective. In addition, the combined treatment of fumaric acid (0.5 g/100 ml)/UV-C (1 kJ/m(2)) reduced the populations of Escherichia call O157:H7, Salmonella enterica serovar Typhimurium, and Listeria monocytogenes inoculated on clover sprouts by 3.02, 2.88, and 2.35 log CFU/g. Alfalfa sprouts were treated with ClO2, fumaric acid, and the combination of fumaric acid/ClO2. The combined treatment was the most effective, and it reduced the total aerobic bacteria by 3.18 log CFU/g as well as the initial populations of E. call O157:H7, S. typhimurium, and L monocytogenes inoculated on alfalfa sprouts by 4.06, 3.57, and 3.69 log CFU/g. These results suggest that the combined treatment of fumaric acid with UV-C or ClO2 can be useful for improving the microbial safety of alfalfa and clover sprouts. (C) 2009 Elsevier Ltd. All rights reserved.