Simultaneous gas chromatographic determination was made on sorbic acid (SOA), dehydroacetic acid (DHA), benzoic acid (BA) and butyl p-hydroxybenzoate (POBA-Bu) in food, using a column of 5% DGS+1% phosphoric acid coated on chromosorb W at 210°C and hydrogen flame ionization detector. Esterification or other pretreatments of these preservatives are not necessary in this method. The calibration curve, obtained by peak height ratio of each preservative and acetanilide (internal standard), has linearity within a range between 0.5 to 2.5μg and the precision of 2.5% or better.
Extraction of these preservatives was carried out with a mixed solution of petroleum ether and ethyl ether (1: 1) from alkaline extracts of foods. The recoveries of each preservative were 50-80%.

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Mineral requirements of Vibrio parahaemolyticus and marine or terrestrial bacteria were studied. The results obtained were as follows:
Terrestrial bacteria showed a moderate growth without any supplement of inorganic salts to the basal medium and they did not take special requirement to minerals.
True marine bacteria required especially minerals. Because, not only NaCl but also the other minerals (K-, Mg-, Ca-salt) in sea water were needed for their growth, and Na ion was indispensable to them. In other words, sea water has a role of nutritional supplement rather than that of osmotic controls on the growth of marine bacteria.
On the other hand, V. parahaemolyticus required NaCl only, but did not take require any other minerals in sea water. In this case, NaCl could be replaced with other salts. That is, such requirement appeared in them depend on their role of osmotic control. The V. parahaemolyticus did not seemed that it belonged to marine bacteria and to be analogous to terrestrial bacteria.

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In order to investigate the method of hygienic treatment of milking machine, we studied the state of the organisms contaminating the raw milk during milking and the effect of chlorine disinfectant on its contaminating bacteria. The plate counts obtained in the examination of the most of the samples by milking machine were of 10⁵ per ml of milk or higher, whereas those of the milk by hand milking were of 10³ per ml of milk or less. The bacterial flora found in the milk and milking machine were the same as found in all the samples.
Four types of bacteria were found commonly present thereof. They were Micrococci, Bacilli, Pseudomonas and Flavobacter. Also many Psyclophylic bacteria were found. From these results, it is clear that the contamination with the organisms was attributable to the unhygienic condition at dairy farms, especially, the carelessness in treating milking machine. The bactericidal effects of chlorine water on these contaminating bacteria were examined in vitro. We found that the amount of available chlorine decreased remarkably when a small amount of milk is mixed e. g., the mixture of 1% milk decreased available chlorine by 50%. Based upon these results, the field experiments were conducted at the dairy farms, instructing them the method of washing milking machine, chlorine concentration, etc. The milk produced thereof was a good quality milk from the bacterological point of view.

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In order to determine milk components and examine food additives in margarine, quantitative determinations were carried out for milk solids, sugar, protein, phosphorus and calcium in 76 brands of margarine and 4 brands of butter.
(1) The amount of milk solids was the largest in household margarine (carton), the average value being 1.04%, followed by school lunch margarine (0.56%) and spread margarine (0.50%). The amount in parchment packed and bakery margarine was very small, the values being 0.33% and 0.37%, respectively.
(2) The ratio of sugar and proteins was affected by milk components, especially by the amount of lecithine when the amount of milk components was small, and protein was present in larger amount than sugar. This tendency was especially marked in spread margarine.
(3) The amount of phosphorus and calcium detected was in proportion to the amount of milk solids and the respective amounts detected in maximum were 294.6 and 360.4ppm.
Although phosphorus is affected by the presence of lecithine and other (proteins), calcium is not affected by such components. Consequently, amount of milk components added can be calculated accurately by the determination of the amount of calcium.

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Four organic acids and vinegar were tested for bacteriocidal properties against Vibrio parahaemolyticus. Acetic, succinic, lactic and tartaric acids and vinegar showed to possess significant activities for this bacterial species in vitro. However, the vibrio cells in fresh fish were not sterilized completely by treatment with vinegar for 2 hours. From these results it would be supposed that the pickling in usual method might not always be an effective procedure enough to prevent this type of food poisoning.

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The ratio of ethylene oxide and carbon dioxide gases was studied, and the most adequate ratio to obtain efficient effect as fungicide and insecticide was described. The state of penetration and adsorption of ethylene oxide gas was found to vary with the quality of the substances to be fumigated.

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[in Japanese]

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