Effect of lactoferrin and its derivatives, high hydrostatic pressure, and their combinations, on Escherichia coli O157:H7 and Pseudomonas fluorescens in chicken filets

Bovine lactoferrin, amidated or pepsin-digested lactoferrin, and activated lactoferrin, all at 0.5 mg/g, and high pressure treatments at 200, 300, 400, and 500 MPa for 10 min at 10 °C, were assayed against Escherichia coli O157:H7 and Pseudomonas fluorescens inoculated on chicken filets at levels of 7.2 and 6.5 log CFU/g, respectively. After treatments, filets were held at 5 °C for 9 days. Antimicrobials, by themselves, reduced counts of E. coli O157:H7 and P. fluorescens by a maximum of 0.6 and 0.8 log CFU/g, respectively. Treatment at 400 MPa, by itself, lowered counts of inoculated E. coli O157:H7 by more than 5 log CFU/g and those of inoculated P. fluorescens by more than 6 log CFU/g. A synergistic effect on P. fluorescens was observed when treatment at 300 MPa was combined with lactoferrin, with a 2.3 log CFU/g additional reduction in counts on day 9, with respect to only 300 MPa treatment. Additional reductions in E. coli O157:H7 counts achieved by combined treatments remained below 0.5 log CFU/g.Industrial relevanceLactoferrin and its derivatives, by themselves, had a limited potential for bacterial control in chicken filets. High hydrostatic pressure reduced efficiently counts of E. coli O157:H7 and P. fluorescens in chicken filets. The combination of high pressure treatments with LF and its derivatives showed a synergistic effect.

► The potent in vitro bactericidal effect of lactoferrin and its derivatives decreased considerably in chicken filets.
► Treatment at 400 MPa reduced counts of P. fluorescens and E. coli O157:H7 on chicken filets by more than 4 log CFU/g.
► The bactericidal effect of LF and its derivatives combined with treatment at 300 MPa on P. fluorescens was synergistic.
► LF and its derivatives combined with treatment at 500 MPa impeded P. fluorescens recovery during storage at 5 °C for 9 days.