Preincubation of Escherichia coli ATCC 25922 with NaCI Increases Its Attachment to Lettuce Surfaces Compared with Other Chemicals

摘要

The inhibition of microbial attachment to food is important for the prevention of cross-contami-nation during food processing. The effect of several chemicals that were added in an Escherichia coli growth medium on the attachment of the bacterium to lettuce was investigated. E路 coli ATCC 25922锛寃hich is reportedly a useful surrogate for E. coli 0157:H7 in surface attachment studies锛?was preincubated in a nutrient broth (NB) containing sodium chloride, potassium chloride, sodium deoxycholate, sodium linear alkylbenzene sulfonate, or sorbic acid. The bacterial cells were placed in contact with cut lettuce in a saline solution at 5鈩?for 24 hours. Only the addition of NaCI in the NB influenced the attachment of E. coli, Salmonella enterica subsp. Enteritidis锛宎nd Klebsiella pneumoniae to the lettuce. The attachment of E路 coli showed the largest significant increase at 2% NaCI. Changes in the attachment levels were not due to surface hydrohobicity or the motility of E路 coli cells. Simitar results were observed for S. enterica although the variation in the degree of attachment of the latter was quite small. These results suggested that the attachment of E路 coli 0157:H7 to food surfaces is influenced by the bacterial growth conditions prior to food exposure and prior to the development of the biofilm; furthermore, the environmental NaCI concentration should be controlled during food processing to prevent the cross-contamination of foods with E.coli.