Purpose: The study aims to assess the survival of osmotically adapted and non-adapted Salmonella spp. in creams and cream-filled brioche-like products.
Methods: Fillings (praline, biscuit) as well as whole brioche-like products (containing praline or biscuit filling), provided by the manufacturer, were inoculated with approximately 6 log CFU/g of osmotically adapted and non-adapted five-strain composite of Salmonella spp. (Typhimurium, Agona, Reading, Enteritidis) and stored aerobically (120mL screw-capped container) at 15, 20, and 30oC. Adaptation of Salmonella took place in creams (praline, biscuit) with aw adjusted 0.88, by adding sterile water to the original filling (aw 0.80-0.82) and incubation at 37oC for 1 h. Survival of Salmonella was assessed at regular time intervals throughout storage using thin layer agar method (n=2x2)
Results: The lower the storage temperature the slower the inactivation of Salmonella spp., since the pathogen survived (4.0-4.5 log CFU/g) after 30 days at 15oC, while at 30oC Salmonella was reduced below the enumeration limit by the 20th day. Salmonella performed the same way in biscuit cream and biscuit-filled brioche, while higher survival was observed in praline cream than in the praline-filled brioche at 20oC requiring 48 and 77 days respectively to reach enumeration limit. Adaptation of Salmonella resulted in higher survival rates compared to non-adapted cells, phenomenon more evident in praline cream and biscuit-filled brioche (reaching population differences up to 2 log CFU/g).
Significance: Assessing the effect of previous adaptation of Salmonella spp. on its subsequent survival in brioche-like products and creams would contribute in development of more accurate predictive models regarding the behavior of the pathogen in bakery-confectionary products.