Studies on the Sterilizing Conditions, Effective Amount of Preservatives and Storable Period of Soft Drinks

Abstract

Soft drinks, such as orange drinks, sour milk drinks, milk coffee drinks, concentrated orange drinks and coffee syrup, were incubated with several kinds of microorganisms such as Shizosaccharomyces pombe, Bacillus subtilis, Aureobasidium pullurans etc., in order to research the storable period in an open bottle, the effective sterilizing conditions, and the ammount of preservatives for each drink. They depended on their pH, sugar content and storage temperature. For instance, the most effective sterilizing temperature of the orange drinks(pH2.9, sugar 13%), the milk coffee drinks(pH6.7, 13%), the concentrated orange drinks(pH2.9, 60%)and the coffee syrup(pH5.0, 48%), under the 10 minutes heating, were 65, 120, 50 and 65°C, respectively. The concentrated orange drinks which were well preserved for 25 days at 10°C without preservatives, never spoiled in 90 days with the addition of 88mg/kg of sodium benzoate. The milk coffee drinks which were preserved only for 6 hours at 38°C without preservatives, spoiled even in the addition of both sodium benzoate 700mg/kg and n-buthyl p-hydroxy benzoate 140mg/kg. To the coffee syrup which was preserved for only 2 days at 38°C, the addition of 140mg/kg of n-buthyl p-hydroxy benzoate was effective, but 700mg/kg of sodium benzoate was not.