Ultrastructure changes induced by dry film formation of a trisodium phosphate blend, antimicrobial solution

Trisodium phosphate (TSP) has been reported to have antimicrobial activity and is approved by the U.S. Department of Agriculture for use in food processing applications. A novel (U.S. Patent 6,184,198), antimicrobial solution containing a blend of TSP, sodium bicarbonate, and sodium carbonate (TSP blend) has demonstrated effective inhibition of microbial contamination in a broad spectrum of applications. This high-resolution cold field emission scanning electron microcopy (LVSEM) investigation details structural changes and dry film formation in various classes of microbes as a mechanism for antimicrobial activity of this solution. The results showed that this TSP blend solution completely inhibited the growth of pathogenic E. coli O157:H7, and Salmonella bacteria, the mold Cryptococcus, as well as a Norwalk virus surrogate-feline calicivirus. Results by LVSEM confirmed that the antimicrobial effect was induced when encapsulating the target microbes in a high lubricity film that is formed around these organisms as the solution dries. The thickness of the film was estimated to be approximately 60 nm.