| Heat treatments are widely extended in food industry since they are able to inactivate microorganisms and their enzymes in a controlled way, ensuring food safety and stability to certain levels. Nevertheless, these treatments have negative effects on heat sensitive compounds and on the organoleptic characteristics of foods. The use of natural antimicrobials is an alternative that, in combination with heat treatments, would help to decrease their intensity, preserving the natural characteristics of the products.;In this Thesis, the microorganisms were chosen among those responsible for food poisoning outbreaks and belonging to different structural groups, in order to check if the differences would affect the efficiency of the treatments applied. A special emphasis has been paid to the heating ratesapplied during thermal treatments, since the influence of this factor on the heat resistance of microorganisms is quite unknown. As natural antimicrobials, a bacteriocin (nisin) and two compounds present in the essential oils of aromatic herbs and spices (carvacrol and thymol) were chosen.;The results obtained in this Thesis, together with the mathematical models used, show the possibility to develop and optimize thermal treatments combined with natural antimicrobials, which would enable food industry to produce safer and better quality foods. |
