Effect of thiamine dilaurylsulfate against Escherichia coli O157:H7, Salmonella Typhimurium, Listeria monocytogenes and Bacillus cereus spores in custard cream

This study was conducted to investigate the antimicrobial effect of thiamine dilaurylsulfate (TDS), known as a vitamin B-1 derivative, on custard cream. The inactivation of Escherichia coli O157:H7, Salmonella Typhimurium, Listeria monocytogenes, and Bacillus cereus spores in custard cream over a 5 day storage period and the influence of storage temperature at 4 and 25 degrees C were investigated. Samples were inoculated with a cocktail of these pathogens and subjected to addition of TDS at concentrations ranging from 0 to 2%. As the concentration of TDS and storage time increased, the inactivation effect increased among all tested pathogens except for B. cereus. The addition of 2% TDS achieved 2.43-, 2.37-, and 0.93- log reductions in inoculated E. coli O157:H7, S. Typhimurium, and L monocytogenes, respectively, during 5 day storage at 25 degrees C. Gram-negative bacteria were more susceptible to TDS than Gram-positive bacteria, and TDS was more effective at 25 degrees C than 4 degrees C. However, regardless of TDS concentration during storage at 4 and 25 degrees C, there were no significant (P > 0.05) differences in populations of B. cereus spores between untreated control and TDS-treated samples. These results suggest that TDS has potential for preventing spoilage of dairy products by improving microbiological safety. (C) 2014 Elsevier Ltd. All rights reserved.