Efficacy of sorbates on the control of the growth of Eurotium species in bakery products with near neutral pH

The effects of sorbic acid and potassium sorbate on growth of different Eurotium isolates when added to a bakery product analogue were tested under different environmental conditions. Water activity of the products was adjusted to values in the range of 0.75–0.90, and storage temperatures were in the range of 15–30 °C. Preservatives were added in concentrations ranging from 0.025% to 0.2%. It was observed that 0.025% and 0.05% concentrations always enhanced the isolates growth, while 0.1% had little preservative effect. Finally, even the highest concentration (0.2%) was not suitable as it only controlled fungal growth under certain water activity and temperature levels. It was concluded that these weak-acid preservatives are not useful when added to bakery products with near to neutral pH.