A comparison of the bactericidal efficacy of 18 disinfectants used in the food industry against Escherichia coli O157:H7 and Pseudomonas aeruginosa at 10 and 20 degrees C

A number of proprietary disinfectant products (18) used in the food industry were tested for their bactericidal efficacy against Pseudomonas aeruginosa and Escherichia coli O157:H7 at 20 and 10 degrees C according to the BS EN 1276 (1997) quantitative suspension test for the evaluation of bactericidal activity of chemical disinfectants and antiseptics used in food, industrial, domestic and institutional areas. At 20 degrees C, 13 products passed at their in-use concentration (under clean and dirty conditions) against Ps. aeruginosa and 15 passed against E. coli O157:H7. The number of products passing the test at 10 degrees C was 11 and 14 for Ps. aeruginosa and E. coli O157:H7, respectively. The products exhibiting reduced efficacy at the lower temperature were amphoterics and quaternary ammonium compounds although some of these types of products were effective at both temperatures. Products that passed against Ps. aeruginosa generally also passed against E. coli O157:H7. Taking all the results together, only 11 of the total of 18 products achieved a pass result under all the parameters tested. This work demonstrates the need for final verification of disinfectant efficacy by undertaking field trials in the food-processing environment in which the product is intended for use.