Polyphosphates show relatively strong antibacterial activity against some bacteria. The use of polyphosphates as food preservative have been studied. In this study sodium hexametaphosphate (HP) was mainly used as polyphosphate, Bacillus subtilis and Escherichia coli as tested bacteria. The action of HP on these bacteria was investigated and the following results were obtained.
The prolongation of lag time was observed in the growth of B. subtilis pretreated with HP for 60 minutes at 30°C. It was found that both lysozyme and penicilline showed strong antibacterial activity against B. subtilis pretreated as above. Ribonucleic acid related substances of low molecular weight were released from the cells of B. subtilis by HP-treatment.
On the other hand, HP showed little antibacterial activity against E. coli under the same experimental condition.
From these results, it was deduced that the differences of the antibacterial activity of HP against B. subtilis and E. coli were based on the structural differences in cell envelope of them.