The validation of the NH Immunochromato O157 test kit

NH Immunochromato O157 is an immunochromatographic test for detection of Escherichia coli O157:H7 and O157:NM in food. It enables simple and rapid testing for the target organism after 18-24 h enrichment. In inclusivity and exclusivity testing, all 50 O157:H7 strains and 15 O157:NM strains tested positive, while all 33 exclusivity strains yielded negative results. Taken together, all 98 strains tested in inclusivity/exclusivity testing were identified correctly. NH Immunochromato O157 method was compared to U.S. Department of Agriculture Food Safety and Inspection Service Microbiology Laboratory Guidebook, Chapter 5.08, reference method for detection of E. coli O157:H7 in 25 g of raw ground beef. The performance of both methods was revealed to be statistically equivalent. Autoclaved and non-autoclaved sample enrichments yielded the same results, showing sterilization is not mandatory for testing with NH Immunochromato O157. The results of the robustness study were not statistically different in all conditions, suggesting that NH Immunochromato produce reliable results under various conditions. However, the users are recommended to follow the instruction when applying sample to the test strip, because a smaller sample volume may produce invalid result.