Use of bioluminescence to evaluate the effects of rapid cooling on recovery of Salmonella enterica serovar Typhimurium DT104 after heat treatment

A bioluminescent reporter strain of Salmonella enterica serovar Typhimurium DT104 was used to evaluate the effect of rapid cooling on bacterial recovery in situ on the surface of a heat treated beef sample.Samples of inoculated beef, 20 mm thick and 50 mm in diameter, were placed in a decontamination apparatus and heated to 90 °C in 30 s using dry heat. Rapid cooling resulted in recovery of bioluminescence approximately 4 h earlier than samples that were left at ambient temperature after heating.This suggests that rapid cooling minimises the damage incurred in S. Typhimurium DT104 during 90 °C treatment and allows for significantly earlier recovery of bacterial metabolic activity, compared to ambient cooling.