Effectiveness of Bacteriophages in Reducing E. coli O157:H7 on Fresh-Cut Cantaloupes and Lettuce

What is it about?

Bacteriophages, are viruses that invade and lyse bacterial cells. Our work shows that bacteriophages specific for the bacterial pathogen E. coli O157:H7 were effective in reducing populations of the pathogen on lettuce and cantaloupe. On 9 cm^2 cut lettuce pieces, the spray application of 7.98 log PFU/cm^2 of bacteriophages (ECP-100) showed a significant reduction in E. coli O157:H7 counts compared to lettuce pieces treated with the control (phosphate buffered saline). Populations of E. coli O157:H7 on lettuce treated with ECP-100 on 0, 1, and 2 days (0.72, < 0.22, and 0.58 log CFU/cm^2 of lettuce) and stored at 4oC were significantly lower than those treated with control (2.64, 1.79, and 2.22 log CFU/cm^2), respectively. Populations of E. coli O157:H7 on cut cantaloupes treated with ECP-100 on days 2, 5, and 7 (0.77, 1.28, and 0.96 log CFU/ml) and stored at 4oC were significantly lower than those treated with control (3.34, 3.23, and 4.09 log CFU/ml), respectively. The effect of bacteriophages was apparent almost immediately after spray treatment in reducing E. coli O157:H7 on lettuce. This study is the first to shows the effectiveness of a bacteriophage mixture to kill E. coli O157:H7 on fresh-cut lettuce and cantaloupes.

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Why is it important?

This work shows that spraying a mixtures of different bacteriophages specific for the foodborne pathogen E. coli O157:H7 can reduce their numbers on fresh-cut iceberg lettuce and cantaloupes.