Investigation of contamination of traditional non-pasteurized ice-creams with E.coli and Staphylococcus aureus in Semnan, Iran-year 2007-8

Ice cream is made from milk, cream, sugar, food additive and may contain preservatives and edible colors as well. This product provides good condition for bacterial growth.This study was conducted to determine the frequency of E.coli and/or Staphylococcus aureus contaminated traditional non-pasteurized ice cream in Semnan. In this descriptive cross sectional study, during two years, 136 samples of nonpasteurized ice creams were investigated in Semnan food and cosmetics laboratory. The samples were investigated for contamination with E. coli and Staphylococcus aureus according to Iranian standard guideline.The isolated bacteria were further identified by conventional bacteriologic tests. Of the 136 samples, 96 (70.6%) were contaminated with E. coli, 53 (38.9%) contaminated with Staphylococcus aureus, 52 (38.2%) contaminated with both bacteria and 39 (28.7%) were non contaminated. Results of this study showed that frequency of traditional non-pasteurized ice creams which were contaminated with E.coli and Staphylococcus a ureus was significantly higher than other surveys.