PURPOSE: To prevent the deterioration in flavor of a food with a high moisture content, e.g. an unbaked cake or half-baked cake, by adjusting the food, particularly a part with a high moisture content, to a specific pH, and enclosing the food in a container with a deoxidizing agent or replacing the gas in the container with an inert gas.

CONSTITUTION: An acid, e.g. acetic acid, citric acid or malic acid, is added to a part with a high moisture content of a cake, e.g. a gelatinized cream or jelly, and adjusted to pH 5W2, and the resultant food is then introduced into a container and enclosed. A deoxidizing agent, e.g. Ageless (Mitsubishi Gas Kagaku KK) or Toppan freshness retaining agent C (Toppan Insatsu KK), is enclosed with the food or the gas in the container is replaced with an inert gas. The cake is then cooled to a low temperature to give great effects, e.g. drying resistance, spoilage resistance and inhibition of fermentation.