To determine the efficacy of the 3 ppm chlorine dioxide against Listeria monocytogenes in clean and spent brine solutions.
This study has demonstrated that Listeria monocytogenes is able to survive in brine solutions composed of 10 and 20% sodium chloride, and 10% calcium chloride after 8 h at 0ºC. However, L. monocytogenes was reduced ~1.2 log10 CFU/m when suspended in 20% calcium chloride brine solutions after 8 h at 0ºC. Approximately 3 log10 CFU/ml reduction was observed after 24 h. In 10 and 20% sodium chloride and 10% calcium chloride brine solutions, a 3 ppm chlorine dioxide treatment for 90 sec at 0ºC resulted in approximately 4 log10 CFU/ml reduction in L. monocytogenes. However, in 20% calcium chloride solutions, L. monocytogenes was reduced approximately 2 log10 CFU/ml in 90 sec. Subsequent experiments demonstrated that previous exposure of L. monocytogenes in brine solutions does not impart protection or enhanced resistance against chlorine dioxide. It appears that the 20% calcium chloride affects the activity of chlorine dioxide by potentially binding up the compound, interfering with activity, or diminishing the oxidizing capacity. As such, the use of calcium chloride brine solutions at a 20% concentration should be carefully evaluated for use in combination with 3 ppm chlorine dioxide. Finally, 3 ppm chlorine dioxide was not effective for reducing L. monocytogenes in spent brine solutions from hot dogs and hams due to the presence of organic and possibly inorganic material.
The efficacy of chlorine dioxide is decreased when added to sodium and calcium chloride and may interact with organic and inorganic compounds in brine solutions. Further research needs to address these issues.