Efficacy of combinations of lactic acid and potassium sorbate against Listeria monocytogenes in chicken stored under modified atmospheres

The combined effect of lactic acid and potassium sorbate on the growth of L. monocytogenes on chicken legs packaged under modified atmospheres (MAP) and stored at 4 degrees C was evaluated. An extended lag phase and a lower maximum growth rate for psychrotrophs and mesophiles was found in those samples packaged in 20% CO2/80%N-2 and washed with different combinations of lactic acid and potassium sorbate compared to those non-treated with organic acids. Legs packaged in 20%C(O)2/80%N-2 and washed with 3.75% lactic acid 3.75% potassium sorbate showed a significant (p < 0.05) reduction in L. monocytogenes compared to untreated chicken legs packaged in MAP, which were approximately 2.63 log units lower in the first ones after 8 days of storage. Moreover, this treatment was the most effective in decreasing the maximum growth rate of L. monocytogenes. The chicken legs packaged in atmospheres containing 20%CO2/80%N-2, had an extended shelf life, but these atmospheres were not able to reduce L. monocytogenes, thus underlining the need for preventive measures so as to control this pathogen. The immersion of chicken legs in a solution containing 3.75% lactic acid 3.75% potassium sorbate can reduce L monocytogenes populations on fresh chicken packaged in a modified atmosphere.