Behavior of Salmonella Enteritidis in the Preparation and Storage of Various Western Fresh Cakes

Abstract

Using whole eggs inoculated with 10⁶/ml of Salmonella Enteritidis (SE), bavarois was experimentally prepared according to the formula and procedure used at a senior's house where a large SE outbreak occurred in 1989. In this procedure, the whole egg was heated to 55.6°C, and the decrease in SE number was small. Bavarois, custard cream and ice cream mix were prepared according to the formulas in text books, inoculated with 10⁵/ml of SE and heated at 58°C, 63°C and 68°C for 3.5 min each. The number of SE decreased to 10⁴/ml level by heating at 53°C for 3.5 min, to less than 10/ml by heating at 68°C for 3.5min, but was positlve in a 25g sample of bavarois and custard cream. By heating at 68°C for 3.5mm which is recommended by the Ministry of Hyglene and Welfare to final users of liquid eggs, SE bacame negatlve in a 25g sample of these three kinds of cakes.
The pH values of four experimentally prepared cakes were roughly 7.0, and the water activities were higher than 0.95 where salmonellas can grow well. Especially the water activity of bavarols made with the recipe at the senior's house was very high. When these four cakes were inoculated with 10²/g of SE and stored at 30°C after completing cooking and cooling to room temperature, SE grew in all the cakes. Especially the SE inoculated into the bavarois prepared according to senior's house formula grew rapidly. When these cakes were stored at 10°C, the growth of SE was very slow in all the experimentally prepared cakes.