Microbiological stability of rice tart stored at ambient temperature after baking

Very popular in Belgium, rice tart is a hot pastry sold in bakeries. It is then consumed at home, for dessert or snack. This study is conducted to investigate the microbiological stability of this foodstuff, from the end of baking to end user by consumers. In this purpose, 108 rice tart samples were collected from each of seven bakeries in five Belgium provinces. Physico-chimical analysis in addition to microbiological analysis were carried out in accordance with the European Regulation EC 2073/2005 and with references methods, to enumerate the total microorganisms count, Staphylococcus aureus, Bacillus cereus as well as Enterobacteria, susceptible likely to contaminate the tarts during the production or after baking. Even when the results meet the microbiological safety standards immediately after baking in all bakeries implicated, a significant (p <0,05) increase of mesophilic aerobic bacteria (ranging from <1 to 7 log cfu/g) and B. cereus (> 3,7 log cfu/g) was observed during the storage at non refrigerated temperature (28 to 30°C). A post-baking recontamination and other parameters like an insufficient baking time or a non uniform distribution of the oven heat could explain the observed bacteria growth. The present study shows that most rice tarts investigated are microbiologically safe. However, the possible increase of bacteria load in this foodstuff attributable to the favorable aw, pH and temperature conditions, highlight the importance of applying good hygienic practices and compliance with storage conditions after baking to ensure consumer safety.