抄録
Using two sorts of microbes, in order to simplify the discrimination between bacteriostatic and bactericidal action, seven officially authorized food preservatives and antimicrobials-benzoic acid, sodium benzoate, salicylic acid, sorbic acid, potassium sorbate, chloramine B and AF-2-were examined by the multiple dilution and methylene blue dyeing method and the following results were obtained.
1) The discrimination of bacteriostatic or bactericidal action was made more accurately by comparing figures of γ ratio-total cell number (TCN) to methylene blue dyed dead cell number (DCN) -in each concentration of preservatives and antimicrobials.
2) The γ values from several testing media enabled us to presume a certain correlation-ship between the food additives and their rules of usage.
3) The influence of pH on acidic preservatives was the same as that of the previous report.
Comparing with the results of previous papers, it is ascertaind that the chlorella method is more convenient than that of saccharomyces for the toxicity test of food additives and the twice dilution method is appropriate for the test.
