Activity of hydrolysed lactoferrin against foodborne pathogenic bacteria in growth media: the effect of EDTA

Lactoferrin was hydrolysed with pepsin and the antimicrobial activity of the resulting hydrolysate (HLF) was studied in 1% peptone, 0.05% yeast extract, 1% glucose (PYG) medium and tryptic soy broth (TSB). HLF was effective against Listeria monocytogenes, enterohaemorrhagic Escherichia coli and Salmonella enteritidis in PYG, however, the highest studied concentration (1.6 mg ml(-1)) did not inhibit growth of any of these organisms in TSB. The addition of EDTA enhanced the activity of HLF in TSB, indicating that the decreased activity of HLF may have been due, in part, to excess cations in the medium.