Decontamination of Salmonella Typhimurium and Listeria monocytogenes on Food-Related Surfaces by a Combination of Sodium Dodecyl Sulfate, Lactic Acid, or Citric Acid Under Different Temperatures

Background: Salmonella Typhimurium and Listeria monocytogenes are among the most important foodborne pathogens, and new methods to remove them from surfaces are useful. The aim of this study was to investigate the bactericidal effect of a combination of sodium dodecyl sulfate (SDS) and some food matrix-related factors such as temperature, salinity, acidity, and exposure time on L. monocytogenes and S. Typhimurium in suspension and on different food industry related surfaces. Methods: The bacterial strains were treated with different concentrations of SDS, citric acid, lactic acid, and NaCl at different temperatures at various times. At least one concentration was selected that caused one or less log reduction in the viability of each bacterium, and the combination treatments were examined in this regard. The best combination was then selected, and its bactericidal effect on the bacteria tested was evaluated on ceramic, stainless steel, and plastic surfaces. Results: The results showed that the sensitivity of the bacteria studied to different disinfectants was different. L. monocytogenes was highly sensitive to SDS, while S. Typhimurium was relatively resistant to SDS. Both bacteria were more sensitive to lactic acid than to citric acid, and the bactericidal effects of the disinfectants were enhanced in the combined treatments at 45º C compared to 35º C treatments. The addition of NaCl to the SDS solution resulted in a strong reduction in the bactericidal effect of SDS. The selected disinfectant removed bacterial biofilms from stainless steel surfaces in a shorter time than ceramic and plastic surfaces. Conclusion: The preparation of combined solutions using SDS and an organic acid at an appropriate concentration and temperature could be useful for removing or reducing bacterial biofilms. Therefore, the combination of SDS and the lactic acid at 45° C can effectively remove pathogenic bacteria from various surfaces.