Wednesday, May 11, 2016
Megaron Athens International Conference Center
Maria Gougouli, Perrotis College, American Farm School (a); Aristotle University of Thessaloniki (b), Thessaloniki, Greece
Ioannis Mourtzinos, Aristotle University of Thessaloniki, Thessaloniki, Greece
Arianne Muscat, University of Malta, Msida, Malta
Vasilis Valdramidis, University of Malta, Msida, Malta
Kostas Koutsoumanis, Department of Food Science and Technology, Faculty of Agriculture, Forestry and Natural Environment, Aristotle University of Thessaloniki, Thessaloniki, Greece
Introduction: Although industrial standards have been greatly improved in the last years, food spoilage by fungi is still a major concern for the food industry. The development of visible mycelia on food products before the end of their shelf-life is one of the most significant quality problems for food products with low pH and water activity values. Since contamination of such products with fungal spores in many cases cannot be avoided, antimicrobial agents are employed. Nevertheless, due to the consumers’ demands for minimally processed and healthier food products, it is essential to study and introduce the natural substances as antimicrobial agents. One promising substance for this purpose can be considered propolis, a resinous substance, collected by honeybees.
Purpose: Given the above, in this study the effect of propolis, pH and NaCl on the formation of visible mycelia by Penicillium expansum, previously identified as a spoiler of dairy products, was assessed.
Methods: Mycelium formation was evaluated in tryptone soy broth (TSB) at 25°C and at different combinations of propolis (0 – 300 μl/ml TSB), pH (2.0 – 4.75) and NaCl concentrations (0% – 18% w/v). In total, 625 visible mycelium formation tests in 125 propolis, pH and NaCl combinations were carried out in polystyrene microtiter plates.
Results: A probabilistic model predicting the P. expansum mycelium formation boundaries was developed.
Significance: The information provided from the developed model can be used as a useful tool in order to control the growth of moulds in foods with specific characteristics (pH, aw) with the use of a natural substances like propolis. Further research objectives of great value for the control of moulds in foods, especially with the use of propolis, include the incorporation of this natural compound in biobased polymer packaging materials, such as edible films or coatings.
