A novel formulation of thiamine dilaurylsulphate and its preservative effect on apple juice and sterilised milk.

Thiamine dilaurylsulphate (TLS), synthesised by a new method, was developed for a formulation with a wide antimicrobial spectrum and evaluated in apple juice and milk. The result of a disc diffusion method showed that TLS, which was synthesised from sodium lauryl sulphate and thiamine hydrochloride, had strong growth-inhibitory effects on Gram-positive bacteria, yeasts, and moulds, but had weak inhibitory effects on Gram-negative bacteria such as Escherichia coli. Moreover, the TLS antibacterial spectrum could be broadened to all microbes by formulation with organic acids, such as gluconic acid or acetic acid, since organic acids have synergistic effects on TLS bacteriostasis. Compared to TLS, the formulation had a better preservation in milk (pH 6.64) by viable microbial counting, although the antibacterial effect of the formulation with TLS showed no significant difference in apple juice (pH 3.98). Therefore, the TLS formulation has wide application and better potential, as a preservative, to enhance food safety.