Inactivation of Salmonella species and other food-borne pathogens with Salmide, a sodium chlorite-based oxyhalogen disinfectant

The biocidal activity of Salmide, a sodium chlorite-based oxyhalogen disinfectant, was tested alone or in combination with disodium ethylenediaminetetraacetate (EDTA) or trisodium phosphate (Na3PO4) against nine Salmonella spp. (choleraesuis, enteritidis, hadar, heidelberg, infantis, montevideo, indiana, typhimurium, worthington) and other selected gram-positive (Bacillus cereus, Listeria monocytogenes, Staphylococcus aureus) and gram negative bacteria (Escherichia coli O157:H7, Pseudomonas aeruginosa). After a 15-min exposure to 10 mM Salmide in distilled deionized water at 37 degrees C, a 2.5- to 6.6-log-cycle reduction in population was observed for all of the 16 strains tested, with the exception of L. monocytogenes ATCC 19111, which appeared to be resistant ( 1-log-cycle reduction). When Salmonella hadar was simultaneously exposed to 10 mM Salmide and 5 or 10 mM disodium EDTA at 37 degrees C for 4 min, the biocidal activity of Salmide was enhanced twofold (6-log-cycle reduction) compared to that observed with 10 mM Salmide alone. Treatment with 10 mM disodium EDTA alone produced no significant inactivation ( 1-log-cycle reduction). Exposure of Salmonella hadar to 55 mM Na3PO4 alone or in combination with 10 mM Salmide yielded a greater than 6-log-cycle reduction, whereas treatment with 10 mM Salmide alone yielded a 4.1-log-cycle-reduction. The presence of protein (as bovine serum albumin) in treatments containing Salmide significantly reduced the biocidal activity. These results demonstrate that Salmide has a rapid and concentration-dependent biocidal activity against both gram-positive and gram-negative food-borne bacterial pathogens and spoilage organisms