Enhanced heat-induced cellular leakage and death of Staphylococcus aureus and Salmonella typhimurium by 2,3 Butanedione.

Influence of diacetyl on cellular leakage and/or death of Staphylococcus aureus (S. aureus; FRI-100) and Salmonella typhimurium (S. typhimurium) in the presence and absence of 30% sucrose and NZ-amine broth at 37, 45 and 55 degrees C was studied using Microbiological and Spectrophotmetric techniques. Diacetyl exists naturally in starter distillate and is usually added to enhance the flavor at the end of the fermentation process. Our objective was to examine its use before the onset of fermentation towards the safety of fermented products. Results showed significant difference (p < 0.05) between control and diacetyl treatments; average mean difference was > 5 log colony forming units per ml (CFU/ml) within 1 hour (h). Interesting trends were also observed when differences with respect to absorbance ratios when data was normalized. Results also showed that diacetyl (0.1%) caused more cellular leakage and death of S. aureus at 45 degrees C as compared to 37 degrees C, and that cellular leakage per se was not directly related to death. Diacetyl, however, caused rapid death of S. aureus and S. typhimurium in the presence of 30% sucrose and NZ-amine broth at 55 degrees C; > 7 log CFU/ml death within 1 and 2 h respectively. We also conducted a study with commercial starter distillate (7%) and proved its ability to control both organisms under the same test conditions within 1 h at 55 degrees C. It is concluded that diacetyl is a potential candidate for the control of foodborne pathogens especially under low water activity conditions such as those encountered during meat fermentation.