In the preservation of fresh fish fillets, the effect of NaNO2 added has been studied. The following experimental results show that the formation of volatile amine or trimethylamine rapidly occurs when the greater part of the added nitrite disappears (This disappearance of NaNO2 may be due to the bacterial consumption).
The ratio of NaNO2 concentration added is nearly proportional to the time of preservation, i. e., the elaption time in which the quantity of volatile base-Natta-ins to 30mg. per 100g. of meat since the blank test shows putrefaction. In the presence of 0.05-0.1% NaNO2, the growth of bacteria is inhibited about for twenty hours. When the bacterial number attains to about 107, the rapid formation of volatile base occurs and PH gradually increases. While the strong preservative. effect is not observed in the case of the only addition of 0.02% NaNO2, it is remarkable in the case of the mixed use of 0.02% NaNO2 and 5% NaCI.