Biocontrol of Salmonella Enteritidis in spiked chicken cuts by lytic bacteriophages ΦSP-1 and ΦSP-3.

The ability of host specific bacteriophages ΦSP-1 and ΦSP-3 to lyse Salmonella in artificially contaminated cuts of pressure cooked chicken meat was evaluated at different temperatures -4 °C, room temperature (28 ± 0.5 °C) and 37 °C applying low and high multiplicity of infection (MOI). Bacteriophages were able to significantly reduce the bacterial counts at all the temperatures studied. At 4 °C, individual application of Φ SP-1 and Φ SP-3 resulted in significant drop in bacterial counts (log10 2.46 and 2.1 CFU/ml, respectively) at high MOI and (log10 0.98 and 0.52 CFU/ml, respectively) at low MOI, when compared to the untreated control on day 3. Similarly at room temperature the drop was log10 3.99 and 3.46 CFU/ml at high MOI and log10 2.51 and 2.3 CFU/ml at low MOI. At 37 °C the drop was log10 1.98 and 2.38 at high MOI and at low MOI it was log10 1.52 and 1.98 CFU/ml. Increased efficiency was observed when phages where applied as cocktail at high MOI as the bacterial counts at the end of day 3 dropped by log10 3.52 CFU/ml at 37 °C and to beyond detectable level at 4 °C and room temperature. The average reduction of bacterial load in the same group was -4 °C (79%), room temperature (92%) and 37 °C (78%).