No paper on the quantitative analysis of sodium polyacrylate (PA-Na) as synthetic thickner in foods has been represented up to the present. The determination of PA-Na by phenyllithium colour reaction is not suitable, because other polymers indicate similar colours too. But the precipitation method by MgSO4 is effective procedure when PA-Na exists in foods with other legal thickner. This method is quantitative one and can be applyied to the examination of processed foods. On the quantitative determination of PA-Na in dry vermicelli or bread, the recovery was fairly satisfactory. The recovery from dry vermicell is worse than that from bread, because the former is very viscous. But this extraction will be made easier by methods of enzyme or acid decomposition. On this determination, the author has need to adjust to pH 7.6-7.8, when phosphate is used, so that PA-Na can be determined quantitatively without the disturbance.
The determination of synthetic antisepties as food additives is very difficuit and its official method has not yet been given by the authorities. For the purpose of finding the best method, various analytical methods were examined. The gas chromatographic technique seemed to be the best. Sorbic acid, benzoic acid, salicylic acid, dehydroacetic acid, methyl naphthoquinone and butyl p-hydroxybenzoate were examined. As their calibration curves were in accordance with the Lambert-Beer Law, they were able to be determined. This technique was applied to jam mixed with sorbic acid, benzoic acid, dehydroacetic acid, methyl naphthoquinone and juice mixed with benzoic acid, dehydroacetic acid. The result has shown fairly good precision with variant coefficient of 3.16%, 2.94%, 4.36%, 3.05%, 3.85% and 3.32% respectively. Considering that various chemicals are to be determined simultaneously, this method seemed to be the best as compared with the others. Analytical conditions a, b and c were as follows: Column: 1m (for a, b and c) Stationery phase: Apiezone grease M (30%) (for a and b) Silicone D. C. 550 (for c) Column temp.: 155° (for a) 190° (for b and c) Carrier gas: He Flow rate: 34ml/min Recorder Sens.: 2mV Bridge Curr.: 200mA Chart Speed: 5mm/min (for a, b and c)
Vibrio parahaemolyticus was isolated from night soil. The night soil was collected from Japanese lavatory (Kumitori-Benjo) in Gifu-shi by honey car. Relation between the percentage of the strain isolated and the number of patients suffered from Vibrio parahaemolyticus was shown in Fig. 1. Because the night soil was laied by for ca. 20 days in lavatory jar, so the close relation is observed among them. The experiment showed the hypothesis about the biocycle of Vibrio parahaemolyticus in nature as follows: Patients suffered from Vibrio parahaemolyticus→faeces contaminated by the microorganismus→collection the contaminated night soil by car→faUing out the night soil to sea water by ship→contamination of the sea water and the subsoil→contamination of the fishes in sea water→man who eat the fishes→Patients→ (upper cycle).